Bio Exam Unit 3

Front 1

Two systems of internal communication and regulation in multicellular organisms

Back 1

Nervous system

Endocrine system

Front 2

Nervous system vs endocrine system

Back 2

Nervous =

-rapid, short-acting responses

-message sent to a specific cell

Endocrine=

-slower, longer lasting response

-message sent to cells throughout body but only received by specific cells

Front 3

Berthold's Experiment

Back 3

Observed male roosters were aggressive and had large waddles and cones and large testes

-removed tests: males lost secondary sex characteristics ---> testes necessary

-removed one teste and put in abdominal cavity: male still had secondary sex characteristics ---> testes sufficient

-Concluded that testes secretes a substance which conditioned blood and blood acted on chicken to produce secondary sex characteristics (substance later found to be testosterone

Front 4

Classify signaling molecules based on distance of target

Back 4

hormones = affect distant target cells; transported via bloodstream

paracrines = affect neighboring cells; through ECF but probably not blood

autocrines = affect same cell that secretes them (some paracrines and hormones can have autocrine functions)

Front 5

examples of paracrines

Back 5

neurotransmitters; cytokines

Front 6

Endocrine cells

Back 6

Cells that secrete hormones

Front 7

Sources of hormones

Back 7

1) Isolated endocrine cells in a tissue

2) Endocrine Glands = aggregation of endocrine cells that secrete hormones into ECF; ductless glands (as opposed to exocrine grands)

3) Neurosecretory Cells = specialized nerve cells; secret neurotransmitters that diffuse into blood and act on distant targets -- called neurohormones

Front 8

Chemical Classes of Hormones & whether lipid or water soluble

Back 8

1) Peptides or Proteins

-Water Soluble

*ex: Insulin and growth hormone

2) Steroid Hormones

-synthesized from steroid cholesterol

-Lipid Soluble

*ex: Estrogen and Progesterone

3) Amine Hormones

-Synthesized from amino acid, typically tyrosine

-Some are lipid soluble, some are water soluble

*ex: epinephrine + TH

Front 9

How water soluble hormones signal

Back 9

--Can't freely cross plasma membrane, but can travel freely in blood:

-Packaged in vesicles and secreted by exocytosis

-travels freely in blood

-binds to receptor on cell surface of target cell, triggering a signal transduction pathway:

---leads to responses in cytoplasm, activating or inactivating an enzyme or altering gene expression

Front 10

How lipid soluble hormones signal

Back 10

--Can diffuse through plasma membrane but can't travel freely in blood

-diffuses through plasma membrane

-binds to transport proteins in blood - keeping it soluble in blood

-diffuses into target cell

-binds to receptor either in nucleus or cytoplasm

---bound hormone receptor alters gene expression

Front 11

first hormone identified

Back 11

secretin

Front 12

Hormone action depends on:

Back 12

Cell type & Receptor Type

-different cells have different signaling cascades, leading to different responses (as do different receptors)

Front 13

Epinephrine secretion and effects

Back 13

-Sympathetic Division of Nervous System stimulates endocrine glands to secrete epinephrine

-different effects on different cells:

--Liver - breaks down glucose (binds to beta receptor)

--Blood vessels in skeletal muscles dilate (binds to beta receptor)

--Blood vessels in intestines constrict (binds to alpha receptor)

Front 14

Evolution of hormone signaling molecules

Back 14

Hormone signaling molecules are highly conserved

--find same compounds and same receptor in many organisms, although the systems have diversified to serve different functions

Front 15

Simple Endocrine Pathway:

Back 15

Stimulus causes Endocrine Cell to Release Hormone which travels in blood to Target Cell triggering a response of target cell -- can act as negative or positive feedback

Front 16

Simple Neuroendocrine Pathway:

Back 16

Stimulus causes Sensory Neuron to Respond stimulating Neurosecretory Cell to release a Neurohormone which travels in blood to Target Cell triggering a response -- can act as negative or positive feedback

Front 17

Oxytocin - example of neuroendocrine pathway:

Back 17

1) Stimulus = baby suckling on breast

2) Sensory neuron stimulates neurosecretory cells to release oxytocin

3) Oxytocin travels through body and binds to receptors on smooth muscle of mammalary glands

4) Causing release of milk

5) Acts as + feedback, causing baby to suckle more

Front 18

What part of the body regulates hormone secretion

Back 18

hypothalamus and pituitary gland

Front 19

Hypothalamus's role in hormone secretion

Back 19

Control Center - integrates nervous and endocrine systems to maintain homeostasis

Front 20

Pituitary Gland - role in hormone secretion

Back 20

Master Gland for hormone secretion and control:

-interface between nervous and endocrine systems

-still gets its control from hypothalamus

Front 21

2 Glands of Anterior Pituitary- Origins + What type of cells it includes

Back 21

1) Anterior Pituitary

-Originates from gut epithelial tissue

-Contains glandular (endocrine) tissue cells

2) Posterior Pituitary

-Originates from neural tissue

-Contains axons from hypothalamic nerve, which go directly into the posterior pituitary

Front 22

Anterior pituitary - overview

Back 22

-Originates from gut epithelial tissue

-Contains glandular (endocrine) tissue cells

---the cells produce & secrete specific hormones

-----some of which are tropic hormones ("in turn" cause release of hormones from other glands)

-Have actual release AND synthesis of hormone here

Front 23

Control of hormone secretion in anterior pituitary

Back 23

Controlled by Hypothalamus:

-hypothalamic neurons lead to release of hypothalamic releasing hormones or release-inhibiting hormones

--these hypothalamic neurhormones reach anterior pituitary traveling through the hypothalamic pituitary portal system (which only goes from nerve terminals of hypothalamic nerves to AP glandular tissue)

Front 24

Anterior Pitutitary Hormones to Remember;

-which are tropic

Back 24

FLAT PEG:

TROPIC:

FSH and LSH = follicle stimulating hormone and luteinizing hormone

-Stimulates testes and ovaries to produce testosterone and pregestins, estrogen

ACTH = Adrenocorticotropic Hormone

-Stimulates adrenal cortex to produce corticosteroids

TSH = Throtropin (thyroid stimulating hormone)

-Stimulates thyroid to produce Thyroid Hormone

Not-Tropic:

Prolactin = Stimulates mammalary glands (to produce milk)

Endorphins and Enkephalins = analgesic effects

GH = growth hormone; stimulates bones (leads to bone growth)

Front 25

Anterior Pituitary Hormone Secretion pathway

Back 25

Stimulus --> Stimulates/inhibit Hypothalamus ---> releases hormones which travel to Anterior Pituitary ----> Releases Tropic Hormones ---> which travels to Endocrine Gland ---> Releases Hormone

Hormone can act as negative feedback on stimulus;

Tropic hormone can ALSO act as negative feedback on stimulus

Front 26

Posterior Pituitary

Back 26

-Originates from neural tissue

-contains axons from hypothalamic neurons

-hormone synthesis occurs in hypothalamus and hormone is transported down axons to posterior pituitary where hormones are stored and released

-Secretes 2 hormones:

--Antidiuretic Hormone (ADH) - targets kidney tubule to increase water retained by kidneys

--Oxytocin - Targets mammalary glands and uterine muscles to stimulate milk flow, uterine contractions, also "cuddle hormone"

Front 27

thyroid gland

Back 27

consists of many follicles (composed of follicle epithelial cells and colloid) and parafollicular cells (C-Cells) in between

Front 28

Two types of hormones secreted by Thyroid Gland

Back 28

1) Calcitonin

2) Thyroxin

Front 29

Calcitonin

Back 29

Produced by Parafollicular Cells (C-Cells) of thyroid

-Helps regulate calcium homeostasis

Front 30

Thyroid Hormone - overview

Back 30

Produced by follicle epithelial cells of thyroid

-increases metabolism; essential fro growth and neural development

-Contains both T3 (triiodothyronine) and T4 (thyroxine)

Front 31

T3 and T4 names

Back 31

T3 = triiodothyronine

T4 = thyroxine

Front 32

How are T3 and T4 produced (and list steps)

Back 32

Via iodination of tyrosine in the follicular cells of throid:

1) Thyrglobulin, which contains ~100 tyrosines, is produced by follicle epithelial cells and secreted into follicle lumen

2) Iodide is actively transported (via iodide pumps) from capillary -> epithelial cell -> Follicle lumen

3) Iodination of Tyrosine Units of Thyroglobulin in follicle lumen

4) Endocytosis of thyroglobulin into epithelial cells

5) Hydrolysis of Thryroglobulin epithelial cells by lysosomal proteases

6) Release of T3 and T4 into circulatory system

Front 33

T4 vs T3

Back 33

T4 = prohormone b/c has little metabolic activity

T3 = active form - capable of binding nuclear thyroid hormone receptors

Thyroid releases 10x more T4 than T3

T4 can be converted to T3 - thus additional layer of control of TH signaling

Front 34

Deiodinases

Back 34

Deiodinases = enzymes that can remove iodine moieties from TH: thus controlling activation and inactivation ot TH within a cell

Type 2 Deiodinase = Activating Deiodinase

-Convertes T4 -> T3 by removing outer ring of iodine

Type 3 Deiodinase = Inactivating Deiodinase

-Converts T4 -> rT3 (reverse T3), which is inactive

-Also converts T3 -> T2 (inactive also)

-does this by removing inner ring of iodine

--Deiodinase activity is controlled in time and tissue specific manners

Front 35

2 ways to get T3

Back 35

1) Secreted by thyroid

2) Type 2 deiodinase converting T4 -> T3

Front 36

How does T3 lead to response in target cell

Back 36

1) Lipid-Soluble T3 readily enters the cell

2) T3 binds to receptor - on cell nucleus (called thyroid hormone receptor)

3) Receptor sits on promoters of genes sensitive to thyroid hormone, called thyroid hormone responsive elements (TRE) thus causing gene transcription upon binding

4) Gene Products are responsible for multiple actions of thyroid hormone

Front 37

Functions of Thyroid Hormon

Back 37

Increases:

Metabolic activity of whole body

Heat Production

Heart Rate & strength of heart rate

Growth Rate & Bone maturation

Mental Processes

Front 38

Insufficient TH in perinatal period causes:

Back 38

Cretinism

Impaired development of skeletal system, CNS, severe mental retardation, short statured, potbellied, coarse facial features, protruding tongue

Front 39

Regulation Pathway of Thyroid Hormone

Back 39

1) Hypothalamic Neurons secrete Thyrotropin Releasing Hormone (TRH) into Portal Vessels

2) TRH travels to AP and stimulates thyrotroph cells to secrete Thyroid Stimulating Hormone (TSH) into circulatory system

3) TSH binds to receptor in thyroid and stimulates thyroid to synthesize and secrete Thyroid Hormone - T3 & T4

4) Negative Feedback: TH decreases sensitivity of thyrotrophs to TRH and also decreases release/production of TRH by hypothalamus

Front 40

Hypothyroidism

Back 40

Main cause: Grave's Disease - autoimmune disorder involving antibodies to TSH receptor, mimicking TSH

- increased TH production b/c Thyroid max stimulated (by antibodies binding to TSH receptor)---> causing hyperplasia/hypertrophy of thyroid follicular cells (causing goiter)

-TSH levels low (due to negative feedback from high TH)

-symptoms: high metabolic rate, heat intolerant, etc.

Front 41

hyperthyroidism

Back 41

Main cause = iodide deficiency

-decreased TH (b/c don't have iodination of thyroglobulin)

-TSH levels high (b/c don't have negative feedback from TH) --> Max stimulation of thyroid (leads to goiter)

Symptoms = low metabolic rate, cold intolerant, etc.

Front 42

TSH and TH levels in hypothyroidism and hyperthyroidism & how both lead to goiter

Back 42

Hypothyroidism:

high TH (b/c antibody binding)

low TSH (b/c negative feedback from TH)

--> goiter results from antibody stimulating thyroid

Hyperthyroidism

low TH (b/c not getting iodination of thyroglobulin)

high TSH (b/c no negative feedback from TH)

---> goiter results from high TSH stimulating thyroid

Front 43

3 organ systems involved in calcium homeostasis (and what they each do)

Back 43

bone = deposition and absorption of bone

kidney = excretion of calcium

intestine = absorption of calcium

Front 44

3 hormones involved in calcium homeostasis

Back 44

Calcitonin = inhibits osteoclasts ---> blood calcium levels fall

Parathyroid Hormone = stimulates bone turnover and decreases Ca2+ exretion by kidne ---> blood calcium levels rise

Calcitriol = promotes absorption of Ca2+ from GI --> blood calcium levels rise

Front 45

Calcitonin

Back 45

plays role in ca2+ homeostasis

Calcitonin = inhibits osteoclasts ---> shifts balance to osteoblasts (which use Ca2+ from blood to make new bone); thus blood calcium levels fall

*Not a major player in adult human Ca2+ homeostasis

-secreted by thyroid

Front 46

Parathyroid Hormone

Back 46

plays role in ca2+ homeostasis

Secreted from Parathyroid Glands (4 small structures on posterior surface of thyroid)

-Ca2+ activates receptors on parathyroid cells which inhibit PTH

---low levels of Ca2+ trigger release of PTH

PTH increases blood calcium levels by:

-Stimulating bone turnover

-decreasing calcium excreted by kidneys

-activating Calcitriol in kindey

Front 47

Calcitriol

Back 47

plays role in Ca2+ homeostasis

synthesized from Vitamin D (which has 2 sources - diet & synthesis in skin from cholesterol in presence of UV light) in liver and kidney

Final step of conversion to Calcitriol occurs in kidney and is activated by PTH

--> promotes absorption of Ca2+ from GI to raise blood calcium levels

Front 48

Glucose

Back 48

key fuel for body; when we eat our body breaks food down to form glucose

Front 49

Insulin

Back 49

hormone that allows glucose to get into cells and provide the energy they need

Front 50

how is insulin released & how does it lead to uptake of glucose

Back 50

-secreted by beta cells of pancreas & travels through body (as does glucose)

-when insulin binds to a cell - activates glucose transporters in cell membranes to pull glucose in

--when glucose is absent, transporters are returned to cytoplasm and glucose uptake is inhibited

Front 51

Diabetes Mellitus

Back 51

Group of diseases marked by hyperglycemia (high glucose levels in blood b/c not entering cells) due to defective insulin production, action, or both

Front 52

Type 1 Diabetes vs Type 2

Back 52

Type 1 = lack of insulin

Type 2 = lack of insulin responsiveness in target cell

Front 53

Diabetes results in...

Back 53

Lack of metabolic fuel:

-can lead to blindness, kidney failure, heart disease, and stroke

Front 54

Treatment of diabetes

Back 54

Type 1 = insulin injections

Type 2 = also insulin injections, b/c body needs a lot since cells less responsive

Front 55

Hormones involved in Glucose Homeostasis

Back 55

Insulin & Glucagon

Front 56

How does insulin regulate glucose homeostasis

Back 56

decreases blood glucose levels:

-after eating, glucose levels rise --> insulin is secreted (by beta cells in pancreas) --> stimulates muscle, adipose, liver to take up glucose --> blood glucose levels fall

Front 57

How does glucagon regulate glucose homeostasis

Back 57

increases blood glucose levels:

-when fasting, blood glucose levels fall --> glucagon is secreted (by alpha cells in pancreas) --> stimulates liver to convert glycogen to glucose --> blood glucose levels rise

Front 58

Adrenal Gland

Back 58

Endocrine gland within a gland - composed of adrenal medulla and adrenal cortex

Front 59

Adrenal Medulla

Back 59

Inside portion of adrenal gland:

-under nervous system control (develops from nervous tissue)

-Produces sympathetic hormones: epinephrine and norepinephrine ---> fight or flight hormones

Front 60

Adrenal Cortex

Back 60

Outer portion of adrenal gland:

-Under hormonal control

-Produces steroid hormones --> which can be divided into 3 functional groups: the three S's "Salt, Sex, and Sugar"

Front 61

Hormone Groupings Secreted by Adrenal Cortex

Back 61

Sal/Sex/Sugar:

(1) Mineralcorticoids = for salt and water homeostasis; effects on kidneys

--ex: aldosterone: stimulates kidneys to conserve Na+ and excrete K+

(2) Sex Steroids = for sexual behavior and development

--amounts negligible compared to gonads (although testosterone secretion by females here could become critical if something wrong)

(3) Glucocorticoids = regulate glucose levels and also protein and fat metabolism

*main glucocorticoid in human = cortisol = stress hormone

Front 62

Main glucocorticoid

Back 62

cortisol = stress hormone released in times of physical or emotional stress;

-triggers non-critical cells to decrease glucose uptake

-immune system reactions are blocked

Front 63

Production pathway for cortisol

Back 63

Stressor ---> Hypothalamus secretes Corticotropin-Releasing Hormone (CRH) which travels to AP via portal system --> AP secreates Adrenocorticotropic Hormone which travels in blood to adrenal cortex --> Adrenal Cortex secretes Cortisol

-Cortisol acts as negative feedback on AP and hypothalamus

Front 64

Different pathways in Adrenal Gland

Back 64

-Corticosteroids from adrenal cortex = respond to long-term stress:

---Hypothalamus (hormone signal) -> AP (hormone signal) -> Adrenal Cortex (corticosteroid)

-Catecholamines from adrenal medulla = short term stress:

---Hypothalamus (nerve impulse) -> Adrenal Medulla (catecholamines)

Front 65

Production of Sex Steroids occurs in _____ in response to _______ from ______

Back 65

Occurs in gonads in response to Gonadotropins (LH and FSH) from Anterior Pituitary

Front 66

How is LH and FSH release controlled

Back 66

By hypothalamic Gonadotropin Releasing Hrmone (GnRH) - which increases release during puberty

Front 67

Male Gonads - what they are, and what they secrete

Back 67

Testes

-secrete androgens; with primary androgen geing testosterone

Front 68

Male Secondary Sex characteristics

Back 68

Axillary and Public Hair

Deepening of voice

Muscle Growth

Front 69

Femal Gonads - what they are and what they synthesize

Back 69

Ovaries

-Synthesize Estrogens and Progesterone

---main estogen = estradiol

Front 70

Female secondary sex characteristics

Back 70

Axillary and pubic hair

breat growth

body fat redistribution

inditation of menstrual and ovarian cycles

Front 71

What determines whether fetus becomes phenotypically male or female?

Back 71

Sex Hormones:

-Early embryo, gonads undifferentiated

-around 7th week -

---androgens are produced in presence of Y-chromosome -- male reproductive structures form

---if lack androgens --- female reproductive structures form

Front 72

Goals for studying hormone action

Back 72

1) Detect, identify, and measure hormone

2) Identify and characterize receptors

3) determine signal transduction pathways in different tissues

Front 73

Immunoassay

Back 73

Can be used to detect and measure hormones

=techniques that use interactions between antigen (hormone) and an antibody to that antigen; can measure half life of hormone

-create a standard curve: measure radioactivity of different known concentrations (when have known concentration of known labeled, here radioactive hormone).

-Then measure the radioactivity of unknown concentration (again with same amount of known labeled concentration).

-find where on the standard curve unknown concentration falls (in terms of radioactivity) to determine concentration amount

Front 74

Affinity Chromotography

Back 74

Allows you to identify receptors and quantify them

-wash a column containing beads with hormone of interest

-hormone binds to bead

-run proteins through column

-proteins with stick to hormone bound to the bead - these are the receptors for that hormone

-one hormone can bind to multiple receptors

-can create drugs to block specific receptors and thus specific responses

Front 75

What type of Receptors to Epinephrine and Norepinephrine bind to in cells of the body

Back 75

Adrenergic Receptors

Front 76

Sexual reproduction

Back 76

Creation of offspring by fusion of 2 haploid cells (gametes) to form a diploid zygote

Front 77

gametes that fuse to form zygote

Back 77

Sperm and egg

Front 78

Asexual reproduction; description and types

Back 78

Creation of new individuals without fusion of gametes

3 types:

1) Budding: New individuals form from bodies of older animals (by mitosis)

-genetically identical to parent

2) Regeneration: Fragment of organism forms complete organism (by mitosis)

-genetically identical to parent

3) Parthenogenesis: Development of offspring from unfertilized egg

-progeny is haploid OR diploid

-most of these species also engage in sexual reproduction

-may be identical to parent or not

Front 79

Pros and cons of sexual and asexual reproduction

Back 79

Sexual:

pros=

-Genetic diversity is created; through which evolution acts

cons =

-less efficient (only 50% of pop produces offspring)

-mating behavior has costs and risks

Asexual

pros =

-no energy for mating

-don't have to find mate

-preservation of successful phenotype = good in constant environments

cons =

-doesn't result in genetic changes = bad in non-constant environments

Front 80

How to get genetic diversity

Back 80

3 Ways:

Gametes produced during meiosis produces genetic diversity 2 ways:

1) Crossing over between homologous chromosomes

2) independent assortment of chromosomes (which homologue goes to which daughter cell is random)

Third way: have different individuals

3) Variation of genetics between any two parents

Front 81

Steps of Sexual Reproduction

Back 81

1) Gametogenesis = making gametes

*spermatogenesis and oogenesis

2) Mating = getting gametes together

3) Fertilization = fusing gametes

* sperm (n) + Egg (n) = Zygote (2n)

Front 82

Which step(s) of sexual reproduction are similar among, and which are different?

Back 82

Gametogenesis and fertilization = similar

mating = varies widely

Front 83

Steps in fertilization

Back 83

1) Sperm and egg recognize each other

2) Activation of sperm

3) Plasma Membranes fuse (of sperm and egg)

4) Egg blocks entry of additional sperm (block polyspermy)

5) Egg is activated metabolically

6) Egg and Sperm nuclei fuse

Front 84

Layers of egg - for sea urchins and humans

Back 84

Sea urchins

Outer = Jelly coat

Inner = Vitelline envelope

Humans

Outer = Cumulus

Inner = Zona Pellucida

Front 85

How is fertilization by the wrong species prevented

Back 85

Lock and Key mechanism

Sperm binds to species specific receptors on inner layer of egg to prevent fertilization by wrong species

In sea urchins: bindin molecules in accrosomal process bind to bindin receptors on egg's vitelline layer

Front 86

Sperm anatomy (for sea urchins; similar for humans)

Back 86

Tail = allows it to swim

Numerous Mitochondria = produce ATP so can swim

Nucleus = haploid

Centriole

Acrosome = membrane enclosed structure on sperm head that contains enzymes and other proteins

Front 87

Accrosomal Reaction - function

Back 87

Allows sperm to recognize and pass through protective layers of egg

Front 88

Accosomal Rxn - steps (in sea urchins)

Back 88

1) Jelly coat releases substances attracting sperm

2) Contact - sperm makes contact with jelly coat, triggering accrosomal rxn

3) Accrosomal Membrane breaks down, releasing enzymes that digest through jelly coat

4) Growth of Accrosomal Process; polymerization of actin causes it to elongate and form accrosomal process which has bindin molecules = key to lock, bind to bindin receptors on egg's vitelline layerr

5) Formation of Fertilization cone - fusion of plasma membranes of sperm and egg;

6) Fertilization Cone draws sperm in: Entry of Sperm Organelles - contributes sperm nucleus and centriole; mitochondria degrade

Front 89

What does the sperm contribute to the zygote?

Back 89

Centriole and sperm nucleus

Front 90

Ployspermy

Back 90

Fertilization of egg by more than 1 sperm

-don't want more than 2n = too many chromosomes (triploidy, etc.)

Front 91

Types of Blocks to Polyspermy in Sea Urchins

Back 91

1) Fast Block = influx of Na+ ions

2) Slow Block = release of Ca2+ and fusion of corticol granules = corticol rxn (caused by releases of corticol granule contents)

Front 92

Fast Block to Ployspermy in Sea Urchins

Back 92

-Influx of Na+ ions (after fusion of plasma membranes) --> depolarizes membrane, preventing fusion of other sperm within the membrane

-occurs 1-3 sec after sperm/egg membrane fusion

-lasts for about 1 minute

Front 93

Slow block to polyspermy in sea urchins

Back 93

Corticol rxn: Series of changes in outer zone of egg cytoplasm to make egg impenetrable to sperm:

1- Sperm entry triggers release of Ca2+ (stored in endoplasmic reticulum of egg)

2 - causing Corticol Granules to fuse with plasma and release contents

3 - Corticol Granule contents block polyspermy:

-enzymes dissolve bonds between vitelline envelope and plasma membrane

-proteins cause water to rush in - causes swelling and formation of fertilization envelope (as vitelline layer is lifted off); fertilization envelope aids in resisting sperm entry

-enzymes degrade sperm binding receptors as envelope hardens

-enzymes cause envelope to harden

Front 94

Which coat triggers accrosomal rxn in sea urchins? In humans?

Back 94

Sea Urchins = Outer Coat (Jelly Coat)

Humans = Inner Coat (Zona Pellucida)

Front 95

Cumulus

Back 95

Outer layer of egg

-contains follicle cells in a gelatinous matrix

-sperm just travels through (no accrosomal rxn)

Front 96

Zona Pellucida

Back 96

Inner layer of egg

-contains glycoproteins

-triggers accrosomal rxn that digests path through zona pellucida (accrosomal rxn similar to that in sea urchins)

Front 97

Blocks to polyspermy in Mammals vs in sea urchins

Back 97

- Don't have fast block

- Still have slow-block

--Sperm binding triggers increase in Ca2+ and cortical reaction

-Don't have fertilization envelope

--But sperm binding molecules ARE destroyed - functions as slow block to polyspermy

Front 98

fertilization envelope

Back 98

Envelope that forms in sea urchins after enzymes from corticol granules cause water to rush in and vitelline layer to be lifted

-aids in resisting sperm entry

Front 99

Diocious Species

Back 99

Species that have separate male and female members

Front 100

Monocious (or hermaphroditic species) - description and types

Back 100

Have a single individual that produces both sperm and egg (still a form of sexual reproduction).

Two types:

1) Simultaneous: Male and Female at the same time

-some species - must mate with another individual

-other species - can self fertilize (still sexual reproduction

2) Sequential: Function as male or female at different times

Front 101

Advantage of monecious species

Back 101

If individuals have low probability of finding mate

Front 102

External Fertilization - description and what it requires

Back 102

Eggs shed by female and fertilized by male in environment (aka "spawning")

-requires environment where eggs can develop without desiccation or heat stress (usually in water)

Front 103

Features of external fertilization that ensure fertilization will occur

Back 103

-Release large numbers of gametes

-release can be synchronized by day length, temperature, etc.

-Sometimes get congregation of potential mates

Front 104

Internal Fertilization

Back 104

Release of Sperm into female reproductive tract

-need to keep egg moist & also a place where sperm can swim to egg

-produce fewer zygotes compaired to external fertilization

-provide more parental care of the young

Front 105

Oviparous vs. Vivipourous Animals

Back 105

Oviparous = lay eggs that can withstand harsh environments (eggs provide more paternal care than external fertilization would)

Viviparous = retain embryo, which develops in reproductive tract (provides much more parental care)

Front 106

Complex reproductive systems that have evolved for internal fertilization

Back 106

Primary Sex Organs = Gonads

Secondary Sex Organs = All additional components of reproductive system, including genitalia (external sex organs)

Copulation = joining of female and male accessory sex organs

Front 107

Male Primary Sex Organ

Back 107

Testes

Front 108

Testicle

Back 108

Testis + Scrotum

-testis is held externally to body in scrotum

Front 109

Sperm travel (in males)

Back 109

remember SEVEN UP:

1) S: Sperm are produced in Seminiferous Tubules of Testis

2) E: Mature and Stored in Epididymis

3) V: Travel through Vas Deferns which goes behind bladder

-seminal vesicle - links up and contributes vital fluids to semen

4) E: joining become Ejaculatory Duct

-sperm passes through Prostate Gland and then Bulbourethral Duct Gland - both of which contribute vital fluids to semen

5) N: nothing

6) U: Ejaculatory duct links up with Urethra - and have common output for urinary and reproductive systems

7) P: Ejaculated through Penis (male copulatory organ)

Front 110

Components of Semen

Back 110

1) sperm = less than 5% of semen

2) Fluids and molecules that support sperm + facilitate fertilization --> are secreted by 3 accessory glands (all are paired structures:

(1) Seminal Fluid (seminal vesicles) ~60% of semen

(2) Prostate Fluid (Prostate Glands) ~30% of semen

(3) Alkaline Secretion (Bulbourethral Glands) small volume

Front 111

Secretions by male sexual accessory glands

Back 111

1) Seminal Fluid (seminal vesicles): ~60% of semen

-seminal vesicles empties into vas deferens

-contributes fructose - nourishes sperm

2) Prostate Fluid (Prostate Gland): ~30% of semen

-gives fluid alkaline properties - neutralizes acidity in male and female reproductive tracts

3) Alkaline Secretion from Bulbourethral Gland (in addition to that secreted by prostate gland): small volume

-also neutralizes acidity in urethra

-lubrication - facilitating sperm movement during climax

Front 112

how sexual stimulation leads to sperm delivery (overview)

Back 112

-Sexual Stimulation produces penile erection - enabling penis to be inserted into vaginaW

Front 113

What is human penis composed of

Back 113

Spongy erectile tissue derived from modified veins and capillaries

Front 114

Steps from Sexual Arousal -> Erection

Back 114

1) Sexual Arousal -> Arousal triggers stimulation from CNS through ANS which causes (through its release of Nitric Oxide, NO):

2) Artery Dilation -> allows more blood to flow into spongy tissue

3) Veins are compressed as vascular compartments expand -> causing them to not be able to empty as much blood

4) Erectile Tissue becomes engorged with blood -> due to actions of arteries and veins; thus facilitating insertion into vagina

Front 115

Erectile Dysfunction

Back 115

Inability to achieve an erection

-Can be treated with drugs that promote vasodialation of the local regulator, Nitric Oxide (NO);

-ex: Viagra

Front 116

Steps of Semen Expulsion

Back 116

-After erection begins, semen is expelled through vas deferntia, ejaculatory duct, and urethra:

1) Semen Emission: Rhythmic Contractions of Glands & Ducts move semen into urethra at base of penis

2) Semen Ejaculation: Contractions by muscles at base of penis cause ejaculation: ejaculate = ~2-6ml of semen, with 50-130 million sperm per mL

3) Prostaglandins in semen stimulate Uterine Contractions ---> cause sperm to move up (only later do sperm swim!)

4) Anticoagulants liquify semen to liberate sperm - so can swim

Front 117

Female primary sex organ

Back 117

2 ovaries

Front 118

Egg travel in females

Back 118

(1) Starts in Ovary

(2) Travels to Oviduct (aka fallopian tube)

(3) Then to muscular Uterus

(4) then base of uterus - the cervix, with small opening

(5) Finally to the vagina

Front 119

Primary Function(s) of male and female sex organs

Back 119

Male:

(1) Produce and Deliver Sperm

Female:

(1) Produce Eggs

(2) Receiving Sperm

Front 120

Sperm Travel in females

Back 120

(1) Sperm is deposited into Vagina

(2) Contractions propel sperm through Cervical Opening

(3) Travels through Uterus

(4) Finally ends in Oviduct - where fertilized

Front 121

How eggs are released and move

Back 121

Ovaries contain many follicles - all follicles are formed at birth;

Ovulation = release of an egg (from ovaries):

-follicle cell bursts, releasing egg into oviduct - fimbria of oviduct collects egg and makes sure it travels to oviduct and not abdominal cavity

-cilia propel egg towards uterus

-neck of uterus is cervix which opens to vagina

Front 122

follicle

Back 122

Functional unit of oveary ; One egg cell surrounded by follicle cells

Front 123

Uterus

Back 123

thick muscular organ lined with endometrium and rich in blood vessels

Front 124

where does gametogenesis occur? (What are gametes called?)

Back 124

In Gonads:

males = testes (gametes = sperm)

females = ovaries (gametes = ova)

Front 125

How are gametes produced (broadly for men and women?)

Back 125

from Germ Cells = present in early development; migrate to gonads when gonads begin to form

Germ cells undergo mitosis to produce stem cells: spermatogenesis and oogenesis --> self-regenerating stem cells that also produce spermocytes and oocytes

Meiosis then produces haploid cells that mature into sperm and ova

Front 126

Spermatogenesis = what it is and where it occurs

Back 126

Production of mature sperm cells

Occurs in seminiferous tubules of testis

-spermatagonia is located in periphery of each seminiferous tubule and developing cells move towards lumen

Front 127

Process of Spermatogonia

Back 127

(1) Male Germ Cells (2n) = 1

**mitosis -->

(2) Spermatagonium (2n) = 1

**mitosis -->

(3) Primary Spermatocyte (2n) = 1

**first meiotic division -->

(4) Secondary Spermatocyte (n) = 4

**second meiotic division -->

(5) Spermatids (n) = 4

**growth and maturation -->

(6) Spermatozoa (sperm) (n) = 4

Front 128

What types of cells (from spermatogenesis) are found in embryo?

Back 128

Male Germ Cells

Spermatogonium

Front 129

What types of cells (from spermatogenesis) are found in adults?

Back 129

Spermatogonium

Primary Spermatocytes

Secondary Spermatocytes

Spermatids

Spermatazoa

Front 130

Oogenesis

Back 130

Production of Mature, unfertilized egg cells

Front 131

Process of Oogenesis

Back 131

(1) Female Germ Cell (2n) = 1

**mitosis -->

(2) Oogonium (2n) = 1

**mitosis -->

(3) Primary Oocyte (2n) = 1

**arrested in meiosis prophase I until puberty

**starting at puberty, first meiotic division-->

(4) Secondary Oocyte (n) = 1 + 1 polar body

**arrested until fertilization

**after fertilization, second meiotic division-->

(5) Ootid (n) = 1 + 2nd polar body (and 1st)

**"growth/maturation" -->

(6) Ovum (egg) (n) = 1 (polar bodies degrade)

Front 132

Why get polar bodies during oogenesis

Back 132

During meiotic division, cytokinesis is unequal:

-most of cytoplasm goes to one daughter cell

-other cell becomes polar body

Front 133

Cytoplasmic Bridges in Spermatogenesis

Back 133

Connect spermatids -->

b/c have 2 X cells and 2 Y cells; Xs have some necessary proteins that Ys are missing; thus need the connection

Front 134

gametogenesis in males vs femals

Back 134

(1) Asymmetry during cytokenesis of meiotic divisions of oogenesis:

-get 1 product in oogenesis

-get 4 products in spermatogenesis

(2) Females have all the primary oocytes they'll ever have;

Males sperm cells continue to develop throughout life

(3) Oogenesis has long periods of arrested development

Spermatogenesis is an uninterrupted process

Front 135

Gonadotropin Relesaing Hormone (GnRH)

Back 135

Released by hypothalamus = key regulator of LH & FSH in Anterior Pituitary

Front 136

What controls male sexual function?

Back 136

Hormones;
-increased production of testosterone beginning at puberty

Front 137

List the steps of increased production of testosterone beginning at puberty

Back 137

(1) Increased GnRH produced by hypothalamus, causes

(2) Release of LH and FSH by Anterior Pituitary

(3)

**LH stimulates Leydig Cells to increase Testosterone

--> Testosterone leads to increased growth rate and development of secondary sex characteristics

**FSH and testosterone control sertoli cells - which control spermatogenesis

(4) Negative Feedback Loops:

**Sertoli Cells also produce inhibin which exerts negative feedback on Anterior Pituitary

**Testosterone can exert negative feedback on hypothalamus and anterior pituitary

Front 138

The Linked cycles in females, and what they do

Back 138

Ovarian Cycle = produces egg and hormones

Menstrual Cycle = prepares endometrium for embryo

Front 139

Ovarian Cycle - features

Back 139

-Woman only has so many: born with ~1 million primary oocytes in each ovary, most degenerate, but a woman will go through ~450 ovarian cycles

-At menopause (end of fertility) may only be a few oocytes left --> ovaries lose responsiveness to gonadotropins as well, thus resulting in a decline of estrogen producton

Front 140

Phases of Ovarian Cycle

Back 140

(1) Follicular Phase: follicular cells produce estrogen and progesterone

-usually one follicle matures completely - releasing egg midcycle

(2) Luteal Phase: Follicle cells left in ovary develop into endocrine gland = corpus luteum

-CL produces estrogen and progesterone for ~2 weeks

-CL degenerates if no fertilization

Front 141

Menstrual cycle - features

Back 141

Prepares environment for fertilized egg

-parallels ovarian cycle

-consists of buildup and breakdown of endometrium:

---endometrium thickens in preparation of embryo (in max state of preparedness for ~9 days)

---if no embryo, sloughing off of endomentrium = menstruation

-human menstrual cycle ~28 days

-human females = receptive to sexual activity throughout their cycles

---unlike most mammals which go into estrus (when receptive; around ovulation)

Front 142

Basic Pathway for release of Estrogen and Progesterone by Follicles and CL

Back 142

(1) Hypothalamus secretes GnRH

(2) AP secretes LH and FSH

(3) Ovary - follicles and CL secrete Estrogen and Progesterone

(4) Estrogen and progesterone travel to uterus;

Also provide feedback:

**Estrogen = positive AND negative feedback to hypothalamus and AP

**Progesterone = negative feedback to hypothalamus and AP

Front 143

hormonal control of Menstrual and Ovarian Cycles

Back 143

(1) Pre-menstrual: high FSH and high LH

**stiumlates:

(2) Follicle Growth in ovaries

**causes:

(3) Increased production of estrogen by maturing oocytes

**causes (positive feedback):

(4) Surge of LH and FSH

**causes:

(5) Ovulation and development of Corpus Luteum

**leads to

(6) CL secretes Estrogen and Progesterone - so levels rise

**stimulating

(7) Development of endometrium (in preparation for pregnancy)

**eventually, if not pregnant:

(8) Corpus Luteum degenerates

**causing

(9) Decrease in Estrogen and Progesterone

**causing (negative feedback):

(10) LH and FSH levels rise --> back to step 1

Front 144

When can pregnancy occur?

Back 144

Over a 5-7 day window around ovulation

--ovulation occurs around day 14 of ovarian/menstrual cycle

B/c:

(1) egg hangs around in oviduct for ~24/48 hours

(2) sperm can live in female reproductive tract for ~ 5-7 days

Front 145

Fertilization - where occurs, and basics on what is happening (and what is formed)

Back 145

Sperm must reach egg in upper oviduct in order to fertilize

fertilization stimulates secondary oocyte to complete secondary meiotic division

fertilization results in fusion of haploid sperm and egg nuclei to form diploid zygote

-undergoes cell division and becomes blastocyst

--blastocyst implants in endometrium

Front 146

Pregnancy Length in humans

Back 146

266 days/9 months

-3 trimesters

Front 147

formation of placenta

Back 147

tissues from growing blastocyst and endometrium develop into placenta

-blood vessels in umbilical cord carry nutrients and oxygen from mother to fetus and carry waste away

---vein = caries in oxygenated blood

---artery = carries blood with waste away

Front 148

Changes in Ovarian Cycle during pregnancy

Back 148

Changes in mother cause it to cease:

----> High levels of estrogen and progesterone prevent pituitary from secreting gonadotropins.

Get high levels as such:

-After fertilization and implantation:

--layer of cells covering blastocyst secrete human chorionic gonadotropin (hCG)

---hCH stimulates CL to produce estrogen and progesterone to prevent menstruation and maintain endometrium

--after CL degenerates (~2nd trimester) -> placenta becomes main producer of estrogen and progesterone

Front 149

first trimester basics

Back 149

main period of organogenesis

-heart beats and limbs form

by end of week 8 all major adult structures are present in rudimentary form = now known as a fetus

Period when most susceptible from damage from drugs/chemicals (because fetus is rapidly developing)

Front 150

Second trimester basics

Back 150

Limbs elongate - fingers, toes, facial features form

fetal movement is felt by motherT

Front 151

Third trimester basics

Back 151

Internal organs mature

Kidneys can now excrete urine

Brain goes through sleep wake cycles

Birth occurs when lungs are mature

Front 152

Stages of Labor

Back 152

(1) Dilation of cervix

(2) Expulsion: delivery of infant

(3) Delivery of placenta

Front 153

Main process that enables childbirth to occur

Back 153

Strong rhythmic contractions

-triggered by hormonal and mechanical stimuli

Front 154

Cause of contractions during birth

Back 154

(1) Increased ratio of estrogen (stimulates contractions) to progesterone (inhibits contractions by increasing activity of oxytocin receptors on uterine wall) by end of 3rd trimester

(2) Fetus pushes more on cervix

(3) Release more oxytocin

(4) Stimulating more contractions

(5) Causing more dilation of cervix (first stage of labor)

Front 155

Failure proof methods for preventing pregnancy

Back 155

(1) Abstinence

(2) Surgical Removal of Gonads

Front 156

Contraception

Back 156

Prevent fertilization of implantation

Front 157

Abortion

Back 157

Termination of pregnancy after fertilized egg has implanted. Two types:

Spontaneous Abortions: miscarriage

Medical Intervention

Front 158

Reproductive technologies

Back 158

Artificial Insemination: Sperm placed in female reproductive tract

Assisted Reproductive Technologies: Unfertilized eggs are removed from ovary, combined with sperm outside body, and replaced in female (ex IVF)

Front 159

Why don't have hormonal contraception for men?

Back 159

Blocks testosterone --> unwanted consequences (decreased sex drive/feminizing)

Front 160

genitalia

Back 160

external sex organs

Front 161

leydig cells

Back 161

produce testosterone; in testicles

Front 162

Sertoli Cells

Back 162

In testicles; enable spermatogenesis

also produce inhibin (exerts negative feedback on FSH production)

Front 163

Development

Back 163

Process in which a multicellular organism undergoes a series of progressive changes that characterizes its life cycle

Front 164

Stages of development in embryos:

Back 164

1. Determination = fate of cell is set

2. Differentiation = becoming specialized in structure and function (i.e., actually becoming cell determined to be)

3. Morhpogenesis = organization and spatial distribution of differentiated cells (includes organ development)

4. Growth = increase in body size by cell division and cell enlargement

Front 165

Cell fate

Back 165

which type of tissue the cell will eventually become

Front 166

What influences cell fate determination

Back 166

differential gene expression and extracellular environment

Front 167

determination vs differentiation

Back 167

determination = a commitment

differentiation = actualization of commitment

Front 168

Cell potency

Back 168

Potential to differentiate into other cell types (declines with development)

Front 169

Greatest level of potency cells to least

Back 169

Greatest

(1) Totipotent

(2) Pluripotent

(3) Multipotent

(4) Unipotent

Least

Front 170

Totipotent

Back 170

Can differentiate into any cell

-early embryo

Front 171

Pluripotent

Back 171

Can differentiate into most cell types - but can't form new embryo

-late stage embryo

Front 172

Multipotent

Back 172

Can differentiate into several related cell types

-Late developmental stages and into adulthood

Front 173

Hematopoetic Stem Cells - what is and potency

Back 173

Stem cell that gives rise to other blood cells

-Multipotent

Front 174

Unipotent

Back 174

Can differentiate into once cell type

-mature organism

Front 175

Two ways cell fate is determined:

Back 175

(1) Cytoplasmic Segregation

(2) Induction

Front 176

Cytoplasmic Segregation

Back 176

Unequal Cytokinesis -- helps determine cell fate

Front 177

How does cytoplasmic segregation help determine cell fate

Back 177

-Determines Polarity - causing Cytoplasmic Determinants to be distributed unequally in egg cytoplasm:

-Cytoplasmic Determinant distribution directs embryonic development

-cytoskeleton contributes to this asymmetrical distribution of determinants:

---microtubules have polarity (grow in + direction only)

---cytoskeletal elements can bind motor protein elements which transport determinants to one side of cell or other

Front 178

polarity

Back 178

the difference between one end of the organism and the other

-develops early in development

-yolk and other factors are distributed asymmetrically --> get two poles: Animal Pole and Vegetal Pole

Front 179

Experiments that show that animal and vegetal poles can differ in developmental potential - thus helping determine cell fate

Back 179

Take 8 cell stage sea urchin embryo - dissect two ways and get different results -->

(A) Let animal and vegetal poles develop separately --> get undeveloped cells on top and abnormal larva on bottom

(B) Dissect L-R so have some of each pole in both sections --> both halves develop into small but normal larvae

Front 180

cytoplasmic determinants

Back 180

Can be specific proteins, small regulatory RNAs and mRNAs

Help direct cytoplasmic segregation which determines polarity and cell fate

Front 181

induction

Back 181

cells in development embryo influence one another's developmental fate via chemical signals known as inducers and signal transduction mechanisms

Front 182

How do inducers control activation of genes

Back 182

through signal transduction cascades:

-most inducers are proteins (or growth factors) so have receptors on cell surface: when bind, goes through signal transduction phase in order to effect cell

-differential gene expression leads to cell differentiation

Front 183

Pannexin Proteins: are only found in the brain;

In a liver cell, what would you find of Pannexin?

Back 183

Pannexin Gene

But NOT pannexin mRNA or Pannexin Protein

Front 184

how do inducers affect transcription?

Back 184

inducer molecules go mostly to cell closest to it

-concentration of inducer affects degree to which transcritption factor is activated

--if high enough, transcription factor will enter nucleus and stimulate gene expression involved in cell differentiation

Front 185

What does fusion of sperm and egg plasma membranes accomplish?

Back 185

-Produces 2n zygote

-Stimulates ion fluxes across egg membrane

-blocks polyspermy

-changes pH of egg cytoplasm (expels H+)

-increases egg metabolism and DNA/Protein Synthesis

-initiates cell division = first steps of development

Front 186

contributions to zygote from egg and sperm

Back 186

Egg:

-haploid nucleus

-cytoplasm = rich in organelles, nutrients, and cytoplasmic determinants

-mitochondria (with DNA)

Sperm:

-haploid nucleus

-centriole -> becomes centrosome, which organizes mitotic spindles for cell division

Front 187

Hemispheres of Frog Zygote

Back 187

Vegetal Hemisphere = lower half, where yolk granules (nutrients) are concentrated

Animal Hemisphere = upper half, highly pigmented, contains haploid nucleus

Front 188

rearrangement of egg cytoplasm in frogs post - summary of what is happening

Back 188

Sperm entry establishes polarity in zygote

-information molecules are thus not divided evenly among daughter cells

Front 189

rearrangement of egg cytoplasm in frogs post - detail of process

Back 189

(1) Sperm Enters in animal hemisphere; causing

(2) Rotation of Outer Cortical Cytoplasm towards site of entry

-causing shift in animal and vegetal poles - start to connect, causing

(3) Gray Crescent forms = band of pigmented cytoplasm opposite sperm entry (becomes future dorsal side of tadpole)

-formation relies on centriole

-important for specifying body axis

-key organizational roles in development embryo

Front 190

How does cytoplamic rearrangement change distribution of critical developmental signals?

Back 190

Centriole (from sperm) initiates cytoplasmic reorganization:

(1) Causes microtubules in vegetal hemisphere to form a parallel array to guide movement of cortical cytoplasm ---> formation of gray crescent

(2) As cytoplasm moves, key developmental signals are distributed

-ex: Beta Catenin transciption factor produced by maternal mRNA

Front 191

Successive Stages following Fertilization

Back 191

(1) Cleavage = to create multicellular embryo (embryo called blastula)

(2) Gastrulation = to produce 3-layered embryo (embryo called gastrula)

(3) Organogenesis = forming organs

Front 192

Cleavage

Back 192

Early cell divisions with NO cell growth

-embryo becomes a solid ball of small cells

Front 193

Embryo called after blastocoel forms

Back 193

blastula

Front 194

blastocoel

Back 194

central fluid-filled cavity that forms in middle of balls of cells during cleavage

Front 195

blastomeres

Back 195

cells of blastula

Front 196

patterns of cleavage depend on

Back 196

amounts of yolk -- which depends on how much embryo needs nutrients from egg

Front 197

Types of cleavage

Back 197

Complete

Incomplete-Discoidal

Incomplete-Superficial

Front 198

Complete Cleavage

Back 198

Completely cleaves through zygotes

-in mammals, frogs, sea urchins, etc.

-blastomeres similar in size (except in frogs - vegetal pole has more yolk, so unequal division - daughter cells in animal pole are smaller)

Front 199

incomplete - discoidal cleavage

Back 199

Embryo forms a blastodisc on top of yolk; cleavage doesn't penetrate yolk

-occurs in eggs with lots of yolk (birds, fish, etc.)

Front 200

Incomplete - Superficial Cleavage

Back 200

Mitosis without cell division

-get many nuclei, known as syncytium: single cell with many nuclei.

-The many nuclei move to periphery and plasma membrane grows inwards around nuclei

-End result = blastoderm

-Occurs in Insects

Front 201

how do cytoplasmic determinants determine planes of cleavage and arrangement of blastomere

Back 201

cytoplasmic determinants determine position of mitotic spindles

-orientation of mitotic spindles is important for planes of cleavage and arrangement of blastomeres

Front 202

types of cleavage based on arrangement of mitotic spindles

Back 202

(1) Radial Cleavage = mitotic spindles form parallel or perpendicular to animal-vegetal axis

(2) Spiral Cleavage = Mitotic spindles form at oblique angles to animal-vegetal axis

(3) Rotational Cleavage = (in mammals)

-First division: Parallel to A-P axis, yields to blastomeres

-Second division: involves 2 planes at right angles to each other (and to the first plane)

Front 203

Features of cleavage in mammals

Back 203

-Complete & Rotational

-Slow & Asynchronous

-Transcriptional changes play role (b/c so slow)

Front 204

Features of Cell division during cleavage in mammals

Back 204

-Early Divisions = loosely associated ball of cells

-8 cell stage = blastomeres change shape and maximize contact with one another to form tight ball (no blastocoel)

-32 cell stage = cells separate into 2 groups:

*inner cell mass = becomes embryo

*Trohpoblast = Sac that forms from outer cells; helps to make blastocoel by secreting fluid

-After 32 stage, embryo is calld a BLASTOCYST (not a blastula)

Front 205

Where do fertilization and cleavage occur?

Back 205

Fertilization = in oviduct

Cleavage = as zygote travels down oviduct to uterus

Front 206

when does human zygote hatch out of zona pellucida

Back 206

when reaches Uterus

Front 207

What prevents early implantation of the egg?

Back 207

Zona Pellucida

Front 208

When does implantation of the egg occur?

Back 208

When troophoblast adheres to endometrium in a specific uterine section (and is aided by adhesion molecules and enzymes)

-anywhere else leads to ectopic pregnancy

---trophoblast wants to make contact with maternal blood, so can lead to hemorrhaging

Front 209

Fate Maps

Back 209

Produced by labeling blastomeres to identify the tissues and organs they generate

Front 210

Mosaic Development vs. Regulative Development - what decides the type

Back 210

Depends on when become "determined"

-Mosaic development = early determination - each blastomere contributes certain aspects to adult mammal

*remove 1 blastomere and portion of embryo won't form

-Regulative Development = late determination = other cells will compensate for any lost cells

Front 211

Key concept behind why twins form

Back 211

Regulative development --- if blastomeres separate into 2 groups, each can become an embryo

Front 212

Twin Types

Back 212

Monozygotic = identical twins from same zygote

-depending on when blastomeres split, can have own or shared placenta

Non-Identical Twins = 2 eggs fertilized by 2 sperm

Conjoined = inner cell mass starts to split but doesn't split all the way

Parasitic Twins = inner cell mass starts splitting but doesn't split all the way

-one side develops normally, other side doesn't and is absorbed by normal side

Front 213

Potency and Monozygotic Twins

Back 213

Shared Placenta = broke off when pluripotent

Two placenta = broke off when totipotent

Front 214

gastrulation

Back 214

massive movements of cells transform blastula into an embryo with 3 tissue layers and distinct body axes

Front 215

Germ Layers

Back 215

(1) Endoerm = innermost layer

-becomes lining of 2 tubules - respiratory and digestive

-also becomes out growth of tubes - pancreas, thyroid, liver, and lungs

(2) Ectoderm = outermost layer

-nervous system, eyes, ears, and skin

(3) Mesoderm = middle layer

-contributes to tissue in many organs: heart, blood vessels, muscle, and bone

Front 216

What does gastrulation begin with?

Back 216

Changes in shapes of blastomere and slowing of mitosis

Front 217

Types of cell movement during gastrulation

Back 217

(1) Invagination = infolding of sheet of cells into embryo

(2) Involution = cells rolling over the edge of a lip into interior

(3) Epiboly = cells moving over surface of embryo towards site of involution

Front 218

At end of gastrulation -

Back 218

-embryo has 3 germ layers

-dorsal-ventral and Anterior-Posterior organization

-fates of specific regions have been determined

Front 219

Gastrulation in sea urchins - steps

Back 219

(1) Vegetal Hemisphere flattens as cells change shape

(2) Vegetal pole cells migrate into cavity and become primary mesenchyme (cell layers of mesoderm)

(3) Vegetal pole invaginates - cells form archenteron which is pulled inward by secondary mesenchyme which have filapodia that attach to ectoderm

(4) Finally, make contact with archeneron + ectodermal cells on top. Opening = blastopore and becomes anus

(other end, end of contact, eventually pinches off to form mouth)

Front 220

Archenteron

Back 220

Primative Gut

Front 221

Filapodia

Back 221

On Secendary mesenchyme of sea urchin; during gastrulation attach archenteron and ectodermal cells on top

Front 222

Gastrulation in the frog - steps

Back 222

(1) Bottle Cells form in gray crescent area and elongate and move to form dorsal lip of blastopore

(2) Cells start moving over lip and involute into the interior - to form mesoderm and endoderm layers

(3) Blastopore Lip surrounds a "pug" of yolk rich cells; another set of bottle cells form and involution causes archenteron & destroys bloastocoel

Front 223

Hans Spemann Experiments - result

Back 223

Reveals how determination occurs

Front 224

Hans Spemann Experiments - details of each

Back 224

Experiment 1: Bisected salamander two ways with different results

(1) bisected gray crescent -> two normal larvae produced

(2) Gray crescent on one side only -> normal developed on side of gray crescent, belly piece developed on other side

----> Conclusion: cytoplasmic factors, such as those in gray crescent, are necessary for normal development

Experiment 2: Transplant (of what should be neural ectoderm to where epidermis should form) in salamander eggs at different stages:

(1) early gastrula -> epidermis did form

(2) late gastrula -> second neural plate formed instead

--> Conclusion: cell fate is determined during gastrulation

Experiment 3: Placed part of dorsal lip in area that should make epidermis

-had second site of gastrulation -> got 2 salamanders

--> conclusion: since blastopore dorsal lip could induce host tissue to form an entire embryo, called the dorsal lip the primary embryonic organizer

Front 225

Primary embryonic organizer in frogs

Back 225

Dorsal Lip

Front 226

How does the dorsal lip in frogs result in body organization?

Back 226

Involutes during gastrulation - thus guiding formation of head, trunk, etc.:

-produces specific growth factor antagonists at different times to achieve different patterns of differentiation on A-P axis

---by interacting with growth factors in adjacent cells (inhibiting or activating), since involuting, changing adjacent cells

Front 227

Gastrulation in Reptiles and Birds (and basically mammals) - Steps

Back 227

(1) Start with blastodisc: flat disc of cells on top of the yolk

--arranged in two layers: hypoblast (lower, will contribute to extraembryonic membrane) and epiblast (upper, will become embryo)

(2) Epiplast cells move towards midline, forming ridge - known as primative streak - continue moving until streak fully formed in midline

Front 228

Primative Streak - features

Back 228

Primative Groove = in middle, where cells migrate through to become endoderm and mesoder

-functions as blastopore

Hensen's Node = most anterior of streak, primary organizer

-equivalent to dorsal lip in amphibians

-in reptiles, birds, mammals

Front 229

Inner cell mass in mammals

Back 229

Two layers:

hypoblast = lower layer - contributes to extraembryonic membranes that surround embryo and helps form placenta

epiblast = upper layer - forms embryo

-upper layer forms amnion - surrounds embryo and is filled with amniotic fluid

Front 230

What helps determine left right symmetry in mammals?

Back 230

Cilia at top of Primative Groove which beat to create asymmetrical flow of extracellular fluid

Front 231

features of gastrulation in placental mammals

Back 231

-Very similar to with reptiles

-Have inner cell mass with the two layers (hypoblast and epiblast)

-have a primative groove

-have Hensen's Node = primary organizer

Front 232

Organogenesis

Back 232

Organ and Organ Systems form - cells from different germ layers participate in formation of single organ

Front 233

neurulation

Back 233

one part of organogenesis (occurs early in organogenesis): initiation of the nervous system

Front 234

chordamesoderm

Back 234

mesoderm closest to midline; prodces notochord

-has organizer functions and induces overlying ectoderm to form nervous system

Front 235

notochord

Back 235

= rod of mesoderm that provides support for embryo (not present in adults, is replaced by vertebral columns in ectoderm)

-produced by chordamesoderm

Front 236

Steps in neurulation

Back 236

(1) Chordamesoderm produces Notochord

(2) Ectoderm lying over notochord thickens to form Neural Plate

(3) Edges of Neural plate fold and a deep groove forms

(4) Folds fuse - forming Neural Tub and layer of epidermal ectoderm

(5) Neural Crest Cells dissociate from neural tube and migrate outward; leading development of connections between CNS and rest of body

Front 237

Failure of neural tube to form

Back 237

At Anterior End = Brain

-Anencephaly (no forebrain develops)

Rest = spinal cord

At Posterior End

-Spina Bifida

Front 238

when does body segmentation occur

Back 238

during neurulation

Front 239

somites

Back 239

body segments; form from mesoderm on either side of neural tube

-produce cells that become vertebrae, ribs, muscles, limbs, and lower skin layer

-guide neural crest cells in peripheral nerve development

Front 240

homeotic genes

Back 240

genes that control body segmentation

-all have a DNA sequence called the homeobox which encodes the homeodomain responsible for DNA binding

Front 241

Hox Genes

Back 241

Homeotic Genes for vertebrates -> control differentiation along A-P axis

-are expressed along A-P axis of embryo in same order as their arrangement between the 3' and 5' ends of the gene complex on the chromosome

-different segments of embryo receive different combinations of gene products

Front 242

Positional Information

Back 242

Molecular cues that control pattern formation

Front 243

morphogens

Back 243

inducer that provides positional information

Front 244

Ex of a morphogen

Back 244

Morphogen Sonic Hedgehog (Shh) - produced by Zone of Polarizing Activity;

-makes an Shh gradient that determines A-P axis

---cells exposed to a higher dose of Shh (closest to ZPA) = little finger forms

---cells exposed to lower dose of Shh (further from ZPA) = thumb forms

(hox genes also play role in this)

Front 245

how dorsal-ventral information is obtained

Back 245

genes provide d-v information:

-tissues in each body segment different based on dorsal-ventral position

Front 246

functions of morphogenesis

Back 246

-cell differentiation

-cell division

-ALSO Apoptosis

Front 247

potency of a zygote; what occurs during development

Back 247

Totipotent -> as development proceeds, cells become determined and lose their totipotency

**but, most differtentiated cells still contain the entire genome and still have the genetic capacity for totipotency

Front 248

Example of Nuclear Transfer

Back 248

Animal Cloning:

Dolly the sheep -

(1) Take udder cell (somatic differentiated cell) and remove nucleus --> becomes donor nucleus

(2) take an egg from a different sheep and also remove the nucleus --> becomes host sheep

(3) Take donor nucleus and place in egg from host sheep and then place the egg back into the host sheep

--> Clone develops in host

-no genetic information is lost as cell passes through developmental stages

-cytoplasmic environment can modify cell fate

Front 249

Stem Cells

Back 249

Rapidly dividing undifferentiated cells that can differentiate into several cell types

Front 250

Stem Cells in adults - potency

Back 250

Multipotent

Front 251

Stem cells in embryonic blastocyst

Back 251

Embryonic Stem Cells = pluripotent

-can be harvested from human embryos

Front 252

Problems with embryonic Stem Cells

Back 252

(1) Ethical issues

(2) Could have immune response - rejection

Front 253

Induced Pluripotent Stem Cells (iPS Cells)

Back 253

Made from differentiated cell in vitro by the addition of several genes essential for undifferentiated state

Front 254

heterotrophs vs autotrophs

Back 254

heterotrophs = derive nutrition from eating other organisms

autotrophs = use solar or inorganic chemical enrgy to synthesize its own organic molecules

all animals are heterotrophs, but all get nutrition (either directly or indirectly) from autotrophs

Front 255

Diet supplies what 3 nutritional needs

Back 255

(1) Chemical Energy for cellular processes

-fuel that allows cellular processes to work

(2) Organic Raw Materials used for Biosynthesis

-come in form of carbon skeletons, which can be used by body to make most molecules in body

(3) Essential Nutrients

-raw materials from carbon skeletons aren't enough to make all molecules we need, so need to get some materials pre-assembled = essential nutrients

Front 256

Food energy conversion to biological work

Back 256

Follows first law of thermodynamics (energy can't be destroyed or created, must be converted)

-mammals balance energy in (fat, protein, and carbohydrates) with energy out (metabolic processes and exercise)

Front 257

All energy needs are met by _____. Explain

Back 257

Food. Breakdown organic molecules to release energy to perform biological work

Front 258

Kilocalorie

Back 258

unit for energy in nutrition

1 kcal - 1,000 calories = 1 Calorie (Cal)

1 cal = amount of heat needed to raise 1 gram of water 1 degree Celsius

Front 259

components of food are broken into ______________. How much energy each provide

Back 259

Protein: 4.1 Cal/gram

Carbs: 4.2 Cal/gram

Fats: 9.5 Cal/gram <--- most energy per gram!

Front 260

Basal Energy Requirement - definition; amount for human adult male and female

Back 260

Amount of energy to just perform basic activities to live

Male = 1600-1800 Cal/day

Female = 1300-1500 Cal/day

Front 261

How is food stored:

Back 261

Carbohydrates --->

-stored in liver and muscle as glycogen

-meets about 1 day's energy reserves

Fats ---->

-stored with little associated water, more compact (ex: in adipose tissue)

-most important form of stored energy (b/c more energy per gram)

Proteins --->

-NOT used for storage but can be metabolized as last resort

Front 262

Chronic Deficit of Calories leads to...

Back 262

Starvation: metabolism of body's own molecules begins:

- first, glycogen and fat are broken down

-finally proteins are metabolized:

---muscles decrease - start to lose kidney function

---eventually results in death - loss of heart, liver, or kidney function

Front 263

Chronic Excess of Calories leads to...

Back 263

Obesity: Excess stored as increased body mass

-first, glycogen stores build

-then excess carbs, fats, and proteins are converted to body fat (first, subcutaneous fat under skin, then body fat goes to ectopic ares such as liver

-can lead to increased health risks:

---type 2 diabetes, cardiovascular disease, and some cancers

---reduced life expectancy

Front 264

Measure obesity

Back 264

Using BMI =

Weight (kg) / Height (m^2)

Normal = 18.5 - 24.9

Overweight = 26-29

Obese = 30-40

Morbidly Obese = 40+

Front 265

Carbon Skeletons

Back 265

building blocks for larger organic molecules

animals require organic molecules to supply them.

Front 266

Example of a carbon skeleton

Back 266

Acetyl Group --- is used to build more complex groups

-must obtain acetyl group from food

Front 267

In addition to an organic source of carbon skeletons, also need a source of organic ______, usually from _____

Back 267

Nitrogen;

usually in amino acids from digestion of proteins

Front 268

Essential Nutrients = Molecules that ______

Back 268

must be obtained in pre-assembled form

Front 269

What are the classes of essential nutrients that food must supply

Back 269

(1) Essential Amino Acids

(2) Essential Fatty Acids

(3) Minerals

(4) Vitamins

Front 270

How many amino acids do animals require?

Back 270

20; but different animals can synthesize different amino acids

Front 271

Essential Amino Acids

Back 271

Amino Acids that a particular animal cannot synthesize

Front 272

How many essential amino acids must human adults obtain from food

Back 272

8

Front 273

What type(s) of food will give humans all 8 essential amino acids at once

Back 273

Animal Proteins

Front 274

Complementary Diet

Back 274

Of Plant foods; eating food together that supply all 8 essential amino acids

-since most plant proteins are incomplete (and must get all 8 around the same time

-ex: grains and legumes

Front 275

Essential Fatty Acids

Back 275

Certain unsaturated fatty acids that animals can't synthesize (have difficulty making double bonds in some fatty acids)

Front 276

Example of an essential fatty acid

Back 276

Linoleic Acid = helps synthesize other unsaturated fatty acids, including signaling molecules and membrane phospholipids

Front 277

Minerals

Back 277

the inorganic required nutrients

Macronutrients and micronutrients

Front 278

types of minerals; examples

Back 278

Macronutrients = mineral elements required in large amounts (ex: Ca2+ b/c of high turnover)

Micronutrients = mineral elements required in small amounts (ex: Iron, Iodide)

Front 279

Vitamins

Back 279

carbon compounds required for growth and metabolism that cannot be synthesized;

(most function as coenzymes or parts of coenzymes)

Front 280

How many vitamins do humans require

Back 280

13

Front 281

Two types of Vitamins

Back 281

Water soluble - including B and C

-excreted in urine if there's excess

Fat Soluble - AEDK

-can accumulate to toxic levels in body fat and liver

Front 282

Vitamin D - hormone or vitamin?

Back 282

both!

Starts as prohormone Califerol

-if don't get enough skin exposure, body can't synthesize it from skin so need it (thus a vitamin)

Front 283

Nutrient Deficiencies can lead to _____; chronic ____ can lead to _____

Back 283

Malnutrition

Chronic Malnutrition can lead to deficiency diseases

Front 284

Deficiency Diseases:

-Causes

-Results

Back 284

Scurvy (lack Vit D) = bleed easily, poor wound healing

Beriberi (lack Vit B1) = extreme weakness

Hypothyroidism (lack Iodine)

Pernicious Anemia (lack Vit B 12)

Front 285

Classifications of animals based on diet

Back 285

Herbivores = prey on plants

Carnivores = prey on animals

Omnivores = prey on plants and animals

Front 286

Type of teeth an animal has is called _____ and it reflects ____

Back 286

Dentition, diet

Front 287

Tooth layers

Back 287

Enamel = composed of calcium phosphate, covers crown

Dentine = bony material in crown and root

Pulp Cavity = contains blood vessels, nerves, and dentine producing cells

Front 288

Dentiton by animal type

Back 288

Herbivores =

-large molars and premolars (to grind)

-modified incisors and canine (for biting off pieces)

Carnivores =

-enlarged canine teeth (killing prey and ripping flesh)

Omnivores =

-multipurpose set of teeth

Front 289

GI Tract also called

Back 289

Alimentary canal

Front 290

Functions of GI System

Back 290

Motility = moving food mouth -> anus

Digestion = mechanical (fragmenting food) and chemical

Secretion = of enzymes to break down food

Absorption = to get food/nutrients into body

Front 291

When is food truly "inside" your body

Back 291

Only after absorption

Front 292

what breaks down macromolecules in GI system (i.e., chemical digestion)

Back 292

hydrolytic enzymes which cleave bonds by hydrolysis

Front 293

Hydrolytic enzymes which cleave bonds by hydrolysis (i.e., chemical digestion) - enzyme name and bonds broken

Back 293

Proteases: Break bonds between adjacent amino acids and proteins

Carbohydrates: hydrolyze carbohydrates

Peptidases: hydrolyze small peptides

Lipases: hydrolyze fats to get fatty acids and glucose

Nucleases: hydrolyze nucleic acids to get component nucleotides

Front 294

What prevent GI Tract (enzymes) from destroying itself?

Back 294

1) Zymogens: digestive enzymes are produced in inactive form, known as zymogens

-must be activated by another enzyme within GI tract lumen

-can't act on cells that produce it

2) Mucus: cells lining gut are protected from enzymes by mucus

Front 295

Key Aspects of Human GI Tract (Organs Beginning to End)

Back 295

1) Oral Cavity: Tongue, mouth, teeth

2) Esophagus

3) Stomach

4) Small Intestine:

-Duodenum

-Jejunum

-Ileum

5) Large Intestine/Colon:

-Ascending Colon

-Transverse Colon

-Descending Colon

6) Rectum

7) Anus

Front 296

Tissue layers of the gut

Back 296

Lumen = gut cavity

-inner layer, exposed to outside

Mucosa = lines gut cavity

-layer of epithelial cells

-may secrete mucus, digestive enzymes, or hormones (depending on location

-may aid in digestion

Submucosa = Layer right under mucosa

-contains blood and lymph vessels and nerves

2 Layers of Smooth Muscle:

Circular Muscle

Longitudinal Muscle

Front 297

what initiates swallowing

Back 297

Food is chewed and tongue pushes bolus to soft palate

Front 298

swallowing: propels food through ____ into ____

Back 298

through Pharynx

into Esophagus

Front 299

enteric nervous system

Back 299

nerve nets in submucosa and between smooth muscle (in GI Tract)

-only forms synapses with other nerves in network

-like a second brain - mostly autonomous (although CNS can influence ststem small amount)

-responsible for communication within GI Tract

Front 300

what allows food to enter the esophagus

Back 300

upper esophageal sphincter

Front 301

peristalsis

Back 301

waves of muscle contractions in esophagus that move food towards stomac

Front 302

what type of muscle is the esophagus

Back 302

Skeletal in upper esophagus (voluntary aspects of swallowing)

Rest is smooth - involuntary

Front 303

How are muscles coordinated in esophagus?

Back 303

by Enteric Nervous System:

-circulatory muscles contract and then longitudinal muscles contract then circulatory muscles contract again to force food forward; followed by waves of relaxation

-as food moves resulting stretch causes next region to contract

Front 304

_________ prevents food from moving backward into esophagus. _________ cause this to relax

Back 304

Lower esophageal sphincter = ring of circular smooth muscle

-waves of peristalsis cause it to relax

Front 305

how does food move in stomach and small intestines?

Back 305

Not as coordinated as in Esophagus

-segmentation movements: segments of gut periodically contract but DON'T generate a wave of contraction that moves in one direction ---> allows food to move back and forth and mix with digestive juices

-although do have some peristalsis to keep food moving down

Front 306

where does chemical digestion begin; how?

Back 306

in the mouth: salivary glands secrete amylase that breaks down carbohydrates

Front 307

How does chemical digestion occur in stomach?

Back 307

Gastric Pits: in stomach, have 3 types of secretory cells (which aid in digestion)-

1) Chief Cells

2) Parietal Cells

3) Epithelial cells that secrete mucus, which protects tissues from the acids and enzymes (against self-digestion)

Front 308

Chief Cells

Back 308

In Gastric Pit of stomach

-secrete Pepsinogen = zymogen of the protease pepsin (which begins protein digested when activated)

Front 309

Pepsin: Purpose, and activation

Back 309

Begins protein digestion

-Low pH in stomach converts inactive pepsinogen to pepsin

-pepsin activates other pepsinogen molecules through autoacatalysis (positive feedback)

Front 310

Parietal cells

Back 310

Secrete HCL which keeps pH ~2 by maintaining H+ concentration difference

Front 311

How do Parietal cells maintain H+ concentration differences?

Back 311

--In the cell: Carbonic Anhydrase catalyzes formation of carbonic acid which dissociates into H+ and bicarbonate

*an antiporter activaley transports bicarbonate out of cell into blood cell and Cl- into parietal cell from blood cell

*another antiporter actively transports H+ into lumen (from Parietal cell) in exchange for K+ ions

--K+ will leak out of cell (down gradient) into lumen, causing it to keep being pumped out - causing H+ to continually return to lumen

--Cl- will additionally leak out into lumen from parietal cell - thus allowing HCl in lumen

----> thus the low pH (which helps activate pepsinogen, and also helps denature proteins)

Front 312

Chyme

Back 312

Mixture of gastric juices and partly digested food in the stomach

Front 313

how does chyme move through stomach

Back 313

stomach walls contract to move chyme to bottom of stomach

Front 314

Pyloric Sphincter

Back 314

Allows small amounts of chyme to enter the small intestine at a time

Front 315

Main function of liver

Back 315

synthesizes bile salts (from cholesterol) and secretes them as bile which flows through hepatic duct to duodenum

Front 316

Gallbladder

Back 316

Site of bile storage

Front 317

How is the gallbladder stimulated to release bile

Back 317

-Fats enter duodenum and signal epithelial cells to release the hormone Cholecystokinin (CKK)

-CKK stimulates walls of gallbladder to contract rhythmically and squeeze bile into duodenum

Front 318

How do Bile Salts emulsify fats in chyme

Back 318

-Have 1 lipophilic end and one hydrophilic end

--Lipophilic ends merge with fat droplets to keep them from sticking together, thus breaking them down into micelles

-this increases the surface area exposed to lipases (which digest fat); and also makes the outside hydrophilic

Front 319

Pancreas main (exocrine) functions:

Back 319

function as both exocrine function and endocrine gland

-Exocrine functions = secrete digestive enzymes to duodenum via pancreatic duct

Front 320

What are some of the main exocrine enzymes secreted by pancreas

Back 320

Tripsinogen = protease zymogen

-activated in duodenum by enterokinase to produce trypsin protease (which activates other zymogens)

Bicarbonate = neutralizes chyme in intestine (b/c other proteases work better and more neutral pHs)

Front 321

where do you finally get monomers in GI Tract

Back 321

small intestine

Front 322

Where does most chemical digestion occur in the GI tract

Back 322

Small intestine; particularly the duodenum

Front 323

Parts of the small intestine; main functions

Back 323

Duodenum = most digestion occurs here

Jejunum and ileum = carry out most absorption

Front 324

How digestion occurs in the small intestine

Back 324

epithelial cells secrete various enzymes which cleave peptides, disaccharides, and lipids :

larger molecules --> monomers (which are then absorbed)

Front 325

Two prime functions of small intestine

Back 325

digestion and absorption

Front 326

anatomical features of small intestine that aid in digestion

Back 326

Increased Surface Area

-has many folds with finger like projections, villi

-villi have smaller projections: microvilli which give intestine enormous surface area for absorbing nutrients

Front 327

How does absorption occur in small intestine (of everything except fat: nucleic acids, proteins, and carbohydrates)?

Back 327

(1) Nutrients are transported across epithelial cells - actively or passively.

(2) From epithelial cells, move into the intestinal capillaries:

(3) Capillaries/Veins -> Hepatic Portal Vein carries nutrient-rich blood to liver

(4) from liver, blood travels to heart, etc.

Front 328

How are nutrients (excluding fat) absorbed by small intestines?

Back 328

Either actively or passively:

-Diffusion

-Facilitated Diffusion --> ex: fructose (moves down concentration gradient)

-Osmosis ---> ex: water

-Active Transport ---> ex: inorganic molecules

-Co-Transport ---> Symporters combine transport of nutrient molecules with Na+

Front 329

How are fats/lipids absorbed in small intestine?

Back 329

(1) Bile Salts emulsify fats into Micelles in the small intestine

(2) Lipases work on micelles - convert to Fatty Acids and Monoglycerides (lipid soluble)

(3) FA and Monoglycerides pass through microvilli membranes (b/c lipid soluble)

(4) In cell, FA and monoglycerides are reformed into Chylomicrons = TG and cholesterol coated with proteins (water soluble)

(5) Chylomicrons pass into lacteals = vessels of lymph system

(6) Lymph eventually drains from lymphatic system into large veins which return blood to the heart

Front 330

Main function of large intestine

Back 330

Absorbs (most) water and ions, and produces feces

Front 331

feces

Back 331

semi-solid mass of waste products

Front 332

too much or too little water absorption by large intestine causes

Back 332

too much = constipation

too little = diarrhea

Front 333

how is feces eliminated?

Back 333

Through anus, which consists of 2 sphincters:

internal sphincter = under involuntary control

external sphincter = under voluntary control

Front 334

Explain mutualistic adaptations in GI Tract

Back 334

Microbiome provide nutritional benefits to humans:

-intestinal bacteria produce vitamins, such as Vitamin K and Biotin

-more microorganisms as move down GI Tract (most in colon)

Front 335

What enables herbivores to digest cellulose

Back 335

Bacteria in cattle rumens produce cellulase which allows cows to digest celluse

Front 336

Cecum

Back 336

microbial fermentation chamber of herbivores

Front 337

3 hormones that aid in digestion

Back 337

Gastrin

Secretin

Cholecystokinin (CKK)

Front 338

How does gastrin aid in digestion

-negative feedback loop

Back 338

-Released from stomach

-Stimulates stomach movements (increasing release of chyme) and secretion of (acidic) digestive juices ---> Stimulates secretion of HCl and Pepsin

*Low pH inhibits Gastrin release

Front 339

How does Secretin aid in digestion

-negative feedback loop

Back 339

-Released from duodenum due to acidity of chyme (chyme release wasdue to gastrin - if acidic, Secretin is released)

-causes pancreas to secrete bicarbonate (neutralizing chyme)

*Slows down stomach movements, causing decrease in chyme release

Front 340

How does Cholecystokinin (CCK) aid in digestion

*negative feedback loop

Back 340

-Released by duodenum epithelial cells when fat in chyme (chyme release was due to gastrin; if fat in it, CCK is released)

-Causes gallbladder to contract and release bile (also causes pancreas to release digestive enzymes

*Slows stomach movements, causing decrease in chyme release

Front 341

How does the liver convert and store nutrients?

Back 341

Gluconeogenesis: converts amino acids and other molecules into glucose

Glycogenolysis: breaks down glycogen into glucose

Also, controls fat metabolism by production of lipoproteins

Front 342

Lipoproteins:

-Description

-Types

Back 342

= Core of hydrophobic fat and cholesterol with covering of hydrophilic proteins

-Can be transported in blood (a way of transporting fat); ex: chylomicrons

TYPES:

High-Density Lipoproteins (HDLs) = "the good"

-high ratio of protein to lipid

-removes cholesterol from tissues and carries it to liver

Low-Density Lipoproteins (LDLs) = "the bad"

-Transport cholesterol in the body

Very-Low Density Lipoproteins (VLDLs) = "the ugly"

-Transport triglycerides to fat cells

Front 343

What causes glycogenolysis and gluconeogenesis? Which occurs first?

Back 343

When blood glucose levels fall, insulin release decreases, and thus glucose uptake by cells also decrease

-Glucagon release by pancreas causes glycogenolysis (short term fasting) and gluconeogenesis (long term fasting)

Front 344

How do glucose levels effect nutrient storage - during absorptive period

Back 344

-Blood glucose levels increase --> pancreas stimulated to produce insulin

-insulin release promotes uptake and utilization of glucose for metabolic activities and for synthesis of glycogen and fat

Front 345

How do glucose levels affect nutrient storage - during post-absorptive period?

Back 345

-Blood glucose levels fall, insulin release decreases, and thus glucose uptake by cells also decrease

-Glucagon release by pancreas causes glycogenolysis (short term fasting) and gluconeogenesis (long term fasting)

-Most cells switch to fatty acids for fuel

Front 346

What is the arcuate nuclues and what does it do?

Back 346

Part of hypothalamus - integrates feedback signals regulating food intake:

-hormones that activate neurons in it inhibit feeding:

-Leptin = released by fat cells in proportion to how much lipid they contain

-Insulin

-hormons that inhibit neurons activate feeding:

-Ghrelin = released by stomach when empty

Front 347

Ob and Db genes in mice

Back 347

Ob = code for protein leptin

Db = code for leptin receptors

-If have ob or db (recessive), will have loss of function of the Gene = weight gain

Front 348

What % water are humans? Where is that water?

Back 348

60%:

2/3 is intracellular

1/3 is in extracellular fluids:

~20% in plasma

~80% in interstitial fluid

Front 349

Why must we maintain water at certain levels in ECF?

Back 349

Solute concentration in ECF determines water balance in the cells

-ECF ionic composition influences cell-function

-important for nitrogenous waste elimination

Front 350

Osmoregulation

Back 350

Management of Body's water content and solute compostion

Front 351

Osomolarity

Back 351

Moles of Osmotically active solute per liter of solution

= (Molarity) X (#particles in solute that dissolve)

Front 352

2 solns of same osmolarity

Back 352

isoosmotic

Front 353

2 solns at different osmolarity:

-one at lower = ____

-one at higher = ____

Back 353

Lower = hypoosmotic

Higher = hyperosmotic

Front 354

Osmolarity is a type of ______

Back 354

Diffusion

Front 355

Water flows from ___ osmotic solns to _____.

Back 355

From Low to High

Front 356

Water transport is ALWAYS _____

Back 356

Passive

Front 357

What are the two factors that cause water movement (which way does water move with both)?

Back 357

(1) Osmolarity Differences (OSMOSIS)

-from hypoosmotic -> hyperosmotic (up gradient)

(2) Pressure Diferences (FILTRATION)

-from high pressure -> low pressure (down gradient)

Front 358

Two types of organisms in terms of balancing water balance - Types, features, Pros and cons

Back 358

Osmoconformers = isoosmotic with environment

-don't actively adjust internal osmolarity

-most stay in pretty constant environments

Osmoregulators = control internal osmolarity independent of environment (either hypoosmotic or hyperosmotic regulation)

-can live in environments that would be uninhabitable for osmoconformers (ex: all terrestrial, fresh water)

-BUT must control internal osmolarity which is energetically costly

Front 359

Most Vertebrates are regulate _____ and ______

Back 359

Osmolarity AND ion concentration

Front 360

Ion Regulators

Back 360

Selective in the ions conserved vs ions excreted

Front 361

Why must nitrogenous waste by eliminated? What is nitrogenous waste?

Back 361

-Breakdown of proteins and nucleic acids lead to nitrogenous products - most commonly NH3.

-Must eliminate to maintain health; also important for effect on osmoregulation

-Most wastes are dissolved in water to eliminate (except CO2)

-must be continuously excreted (NH3 very toxic), but water soluble so will also lose water, or converted

Front 362

3 Ways Animals excrete Nitrogen

Back 362

(1) Excrete Ammonia = ammonotelic Animals

(2) Convert ammonia to Urea to excrete = Ureotolic Animals

(3) Covert Ammonia to Uric Acid to excrete = Aricotelic Animals

Front 363

Features of Ammonia and ammonotelic animals

Back 363

-animals = aquatic animals and most bony fish

-Toxic

-ammonia is Water Soluble

-excreted via diffusion across gills (usually passive)

-low energetic cost of excretion

Front 364

Features of Urea and Uretolic animals

Back 364

-animals = mammals, most amphibians, cartilaginous fishes

-urea is water soluble (important for placenta - can pass through)

-converted from NH3 to Urea (through CO2)

-Relatively Non-Toxic

-High Energetic cost of excretion

Front 365

Features of Uretelic Acid and Uricotelic Animals

Back 365

-Animals = birds, insects, and reptiles

-Convert NH3 to Uric Acid

-Relatively Non-toxic

-insoluble in water (important so doesn't expose embryo in egg)

-excreted as semi-solid with little water loss

-high energetic cost

Front 366

humans mostly excrete nitrogenous waste as ____ but also secrete ____ (too much of which can lead to gout) and ______

Back 366

Mostly = urea

Also (too much of can lead to gout) = uric acid

And = ammonia

Front 367

Excretatory System

Back 367

The organs that control volume, concentration, and composition of the ECF and secrete wastes

Front 368

Urine

Back 368

Output of excretatory systm; fluid containing nitrogenous wastes

Front 369

3 Key processes in urine formation

Back 369

(1) Filtration = using pressure differences to separate the majority of wastes

(2) Secretion = process of removing more waste

(3) Reabsorption = reabsorbing waste into blood that is not to be remoed

Front 370

What are the two main mechanisms of excretatory systems

Back 370

(1) Body Fluid is collected

-through filtration through semipermeable membrane (excludes cells and large molecules)

-pressure forces water and small solutes into excretatory systems

-fluid collected = filtrate (once in excretatory tube)

(2) Composition of body fluid is adjusted

-active transport to reabsorb valuable solutes

-non-essential solutes and wastes are secreted

Front 371

How do circulatory systems play a role in excretatory systems

Back 371

Filtration is driven by pressure differences - if don't have a circulatory system (or it is open), must approach filtration differently (or not at all

Front 372

Describe Protnephrida Excretatatory features

(and features of an organism that has it)

Back 372

Ex: Flat worm = no circulatory system;

-Network of tubules:

*Tubule has a flame cell with a tuft of cilia

(1) Cilia of Flame cell beat inside tubule, leading to negative pressure in tubule

(2) Causing fluid to move in between tubule cells

---In end -> Filtrate is less concentrated than ECF, and exits through pores (thus conserve salts and excrete water)

Front 373

Describe features of Metanephridia excretatory system (and features of an organism that has it)

Back 373

Ex: Annelids (Earthworms), with closed circulatory system

Ciliated Nephrostome -> tubule -> nephridiope (open to outside)

(1) High pressure inside circulatory system filters blood into coelom (Coleomic/Body Cavity)

(2) Cilia on Nephrostomes guide coelomic fluid into Tubules

(3) In tubules, have active Reabsorption and Secretion into the filtrate

-> In end, have dilute urine (usually in a moist environment)

Front 374

Describe features of Malphigian Tubules (and features of an organism that has it)

Back 374

Ex: Insects, open circulatory system

**USES ACTIVE TRANSPORT, NOT FILTRATION

Blind ended tubules open to gut

(1) Tubules use active transport to transport uric acid, K+ and Na+ into tubules and water out

(2) Waste travels to gut; in hindgut, Na+ and K+ are actively reabsorbed into hemolymph cavity (water follows osmotically)

(3) Uric Acid forms colloidal suspension and eliminates waste (with little water)

***in end, have concentrated urine (with little water)

Front 375

three examples of invertebrate excretatory systems

Back 375

Protonephridia

Metanephridia

Malphigian Tubules

Front 376

key features of the nephron

Back 376

Glomerulus = ball of capillaries, site of blood filtration, makes direct contact with:

Bowman's Capsule = first part of tubule

Renal Tubule = filtrate passes through here, cells modify filtrate by reabsorption and secretion of solutes

Afferent Arteriole = blood enters glomerulus from here

Efferent Areteriole = blood leaves gloerulus from here

Peritubular Capillaries = transport substances to and from renal tubes

Front 377

bowman's capsule

Back 377

encloses glomerulus

site of blood filtration

Front 378

cells of Bowman's capsule

Back 378

Podocytes = in direct with glomerular capillaries

Front 379

Pressure drives water and small solutes out of _______ and into _______

Back 379

Out of glomerular capillaries and into Bowman's Capsule

Front 380

Why is there a high filtration rate between Bowman's capsule and glomerular capillaries

Back 380

1) High capillary blood pressure

2) High permeability of glomerular capillaries and podyctes

Front 381

Travel of filtrate (by large organ)

Back 381

Kidney ---> Ureters (collected here) ----> Urinary Bladder ----> Urethra (expels filtrate)

Front 382

How does urethra expel filtrate

Back 382

Have 2 sphincters at base of urinary bladder

Smooth muscle sphincter ---> involuntary control

Skeletal Muscle Sphincter ---> voluntary control

Front 383

Key analogy of Kidney

Back 383

Outer Cortex

Inner Medulla -> broken into renal pyramids

Renal Pyramids: collecting duct nephrons go through, collect filtrate into pelvis

Pelvis: funnel shape extension of ureter; collects filtrate

Renal Artery = bring blood supply

Renal Vein = after filtration, blood leaves

Front 384

Tubule Sections of Nephron starting at glomerulus

Back 384

1) Proximal Convoluted Tubule (PCT)

2) Loop of Henle: 3 segments:

----1-Thin Descending Limb

----2-Thin Ascending Limb

----3-Thick Ascending Limb

3) Distal Convoluted Tubule

4) Collecting duct

(eventually leads to pelvis and ureter)

Front 385

Peritubular capillaries

Back 385

Surround proximal and distal convoluted tubule

Front 386

Vasa recta

Back 386

Network of peritubular capillaries parallel to the loops of Henle and Collecting Duct

-drain off into venule, then vein to renal vein and back to systemic circut

Front 387

Proximal Convoluted Tubule:

-main function

Back 387

Site of most reabsorption of water and solutes

-Active transport of Na+, glucose, and Amino Acids out of Tubules, and water follows osmotically -> taken up by peritubular capillaries and back to rest of body

Front 388

PCT

-features

Back 388

-Many microvilli --> increase surface area

-Many mitochondria --> important for Active Transport

Front 389

Importance of Loop of Henle

Back 389

Concentrates urine (due to countercurrent multiplier) -> due to tubular fluid flowing in opposite directions in ascending and descending limbs, which leads to creation of solute gradient in renal medulla (increasing osmolarity of ISF from outer cortex to inner medulla)

Front 390

How does the Loop of Henle lead to increased concentration of inner medulla

Back 390

Cells of loop differ anatomically:

Thin Descending Limb & Thick Ascending Limb:

-No microvilli

-Few mitochondria

Thick Ascending Limb:

-many mitochondria = for active transport

Front 391

How different segments of the Loop of Henle vary

Back 391

Descending = losing water (many aquaporins)

Ascending = Losing ions (few aquaporins)

Thin = passive diffusion (few mitochondira)

Thick = Active transport (many mitochondria)

Front 392

Thin descending Limb:

Permeability

What losing (and how)

Osmolarity

Back 392

Permeable to water, impermeable to Na+ and Cl-

-Loses water to ISF (via diffusion)

-Before entering, osmolarity in tubule is same as in blood plasma

Front 393

Thin ascending limb:

permeability

what losing (and how)

osmolarity

Back 393

Permeable to Na+ and Cl-, impermeable to water

-loses NaCl to ISF (via passive diffusion)

-Beforing entering, osmolarity is very high in tubule

Front 394

Thick ascending limb:

permeability

what losing (and how)

osmolarity

Back 394

-Impermeable to Water

-Loses NaCl to ISF (via active transport)

Front 395

Purpose of blood flow through medulla (through vasa recta

Back 395

-Tubule needs nutrients, but vasa recta must conserve the concentration gradient. Does by:

-blood flows down descending vasa recta (which is proximal to ascending loop of henle): loses water and gains solutes

-blood flows down ascending vasa recta (which is proximal to descending loop of henle): gains water and loses solutes

Front 396

aquaporins

Back 396

membrane proteins that form water channels - insert into cell membranes (on both sides of cell - facing lumen and facing bloodstream)

Front 397

Where are there lots of aquaporins found in renal tubules; where are there few

Back 397

Lots = PCT, and descending loop of henle

few = Ascending loop of henle

Front 398

osmolarity of ISF and Tubules ______ as you go down

Back 398

Increases

Front 399

Distal Convolutd Tubule:

main function

Back 399

Fine tuning of ionic compostion and water reabsorption:

-Active secretion and reabsorption of: Calcium, Phosphate, Bicarbonate, and Potassium

-Hormone regulation: PTH and other hormones work here

Front 400

Collecting duct:

-where fluid comes from

-composition of fluid

-function

Back 400

Comes from Tubule (DCT)

-has same concentration as blood plasma but different composition ---> now mostly urea

-in collecting duct, concentrate uring:

*is permeable to water --> increases osmolarity of filtrate

-urea diffusion out adds to osmotic potential

-in end, concentration same as ISF

Front 401

Two ways that kidneys remove H+/add HCO3- from/to the blood

Back 401

(1) Through HCO3- conversion:

1-HCO3- is filtered out of blood at gomerulus and into the tubule lumen & Renal tubule cells secrete H+ into tubule fluid

2-H+ and HCO3- react to form CO2 in tubule lumen

3-CO2 diffuses back into tubule cells

4-CO2 is converted back into HCO3- in tubule cells and transported to ISF/blood

(2) Through NH4+ formation

1-NH3 and HCO3- are produced in tubules by metabolism of glutamine

2-HCO3- is transported to ISF/Blood

2-NH3 is transported to lumen and combines with H+ to produce NH4+

Front 402

Results of kidney failure

Back 402

Salt and Water retention = high blood pressure

Urea Retention = uremic poisoning

Decreasing pH = acidosis

Front 403

Dialysis Treatment

Back 403

Pass blood through membrane channels bathed in a plasma like soln to remove waste:

1-take arterial blood from patient

2-dialyze blood across semipermeable membrane bathed with soln similar in concentration to blood plasma:

--high glucose conc -> dialysis fluid has higher osmolarity than blood blasma, so water diffuses out of blood

--concentration of ions that are the same in both = no net mvmt

--bicarbonate ions = soak up H+, removing excess H+ from blood

3-used dialysis soln is discarded and blood returned to patient via a vein

Front 404

Glomerular Filtration Rate

Back 404

Volume of blood plasma filtered per unit time

Front 405

Pair of humans filter ____ Liters per day. Most is _____

Back 405

~180L

Most is reabsorbed

Front 406

Main 2 mechanisms for ensuring high glomerular blood pressure (to maintain high GFR)

Back 406

Dilation of afferent arterioles

Constriction of efferent arterioles

Front 407

Name 4 hormones that can result in altered kidney function

Back 407

Angiotensin: increase BP

Aldosterone (release stimulated by Angiotensin): increase BP

ADH: increase BP

ANP: decrease BP

*increasing BP = increased GFR

*decreasing BP = decreased GFR

Front 408

Describe how Renin release causes an increase in GFR

Back 408

(1) If GFR falls, kidneys release the enzyme renin

(2) renin activates the hormone angiotensin (by converting angiotensinogen to angiotensin)

(3) Angiotensin raises GFR (by increasing BP):

1-constricts efferent renal arterioles

2-constricts peripheral blood vessels

3-stimulates release of aldosterone from adrenal cortex - which increases Na+ reabsorption

Front 409

How is renin released

Back 409

DCT makes contact with glomerular afferent and efferent arterioles

-Macula Densa = specialized cells in tubule ---> detect concentration of NaCl, if low, signal to:

Juxtaglomerular Cells = specialized cells in arteriole ----> release renin

**this can occur b/c if GFR is low, there is more time, so more NaCl is reabsobed, so NaCl is low -> so renin is released, leading to increased BP

Front 410

how does ADH regulate blood pressure and blood osmolarity

Back 410

Insertts aquaporins on collecting duct to increase water permeability ---> leading to water retention which increases blood pressure decreases osmolarity

Front 411

how is ADH release controlled

Back 411

Osmoreceptor Neurons in hypothalamus: detect high blood osmolarity --> triggers release of ADH ---> increases blood pressure by increasing water retention

Stretch Receptors in Aorta and Cartoid Arteries:

detect high blood pressure --> inhibits release of ADH ---> decreases blood pressure

Front 412

ANP

Back 412

Atrial Natriuretic Peptide

Front 413

How does ANP regulate blood pressure

Back 413

-increased venous return stretches atria and muscle fibers release ANP

-ANP leads to decreased reabsorption of Na+ in the kidney

-increasing loss of Na+ and water ---> decreases blood volume and pressure

Front 414

After drinking lots of water, what hormone will increase

Back 414

ANP

Front 415

Different species have different loops of henle. How do differing loops of henle reflect ability to concentrate urine

Back 415

Long loops = very concentrated urine

-ex: desert rat - wants to conserve water

Short loops = less concentrated urine

-ex: birds, but use uric excretion as water conservation mechanism