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76 Cards in this Set

  • Front
  • Back
Exocrine glands
release enzymes into external environment through ducts

include:
1. sweat
2. mucous
3. digestive
Endocrine glands
release hormones directly into body fluids

effects are (when compared to nervous system):
1. slower
2. less direct
3. longer lasting

alter metabolic activities, regulate growth and development, and guide reproduction

works in conjunction with nervous system
Receptors
all hormones act by binding to protein receptors

highly specific for its hormone

reduction or increase of receptors can regulate hormones

can be on the membrane or inside the cell
3 types of hormones
1. peptide
2. steroid
3. tyrosine derivatives
Peptide hormones
derived from peptide

large or small and often include carbohydrate portions

manufactured in rough ER as a perprohormone

water soluble, move freely through blood

difficulty diffusing through cell membrane
effector
target cell of hormone

cell that hormone is meant to affect
hormone-receptor binding
instead of diffusing through membrane, peptide hormones bind to membrane-bound receptor

1. receptor may act as ion channel
2. activate or deactivate intrinsic membrane proteins that also act as ion channels
3. activate intracellular second messenger (cAMP, cGMP or calmodulin) which activates or deactivates enzymes and or ion channels and often creates "cascades" that amplify effect of hormone
Peptide hormones to know:
1. anterior pituitary hormones: FSH, LH, ACTH, hGH, TSH and Prolactin
2. posterior pituitary hormones: ADH and oxytocin
3. parathyroid hormone: PTH
4. pancreatic hormones: glucagon and insulin
Steroid hormones
derived from and often chemically similar to cholesterol

formed in smooth ER and mitochondria

lipids, require protein transport molecule in order to dissolve in blood stream

lipid soluble, diffuse through cell membrane of effector

once inside cell, combine with receptor in cytosol, which transports it into nucleus and acts a transcription level

typical effect is to increase certain membrane or cellular proteins within effector
steroid hormones to know:
1. glucocorticoids and mineral corticoids of adrenal cortex: cortisol and aldosterone

2. gonadal hormones: estrogen, progesterone, testosterone
Tyrosine derivative hormones
thyroid hormones

lipid soluble and must be carried in blood by plasma protein carriers

bind to receptors inside nucleus of effector

increase transcription of large numbers of genes in all cells of body
Tyrosine derivative hormones to know:
1. T3 (triiodothyronine contains 3 iodine atoms)

2. T4 (thyroxine contains 4 iodine atoms)

3. catecholamines formed in adrenal medulla: epinephrine and norepinephrine (water soluble and dissolve in blood, bind to receptors on effector and act through second messenger system)
negative feedback
body responds in attempt to correct back to normal
Anterior Pituitary
located in brain, beneath hypothalamus (controls release of anterior pituitary hormones by releasing inhibitory hormones)

6 peptide hormones:
1. human growth hormone (hGH)
2. adrenocorticotropin (ACTH)
3. thyroid-stimulating hormone (TSH)
4. follicle-stimulating hormone (FSH)
5. leutinizing hormone (LH)
6. prolactin
Human growth hormone (hGH)
peptide

stimulates growth in almost all ells

increases: episodes of mitosis, cell size, rate of protein synthesis, mobilization fat stores, use of fatty acids for energy

decreases: use of glucose
Adrenocorticotropic hormone (ACTH)
peptide

stimulates adrenal cortex to release glucocorticoids via second messenger system (cAMP)

stimulated by stress, glucocorticoids are stress hormones
Thyroid-stimulating hormone (TSH)
peptide

stimulates thyroid release of T3 and T4 via second messenger system (cAMP)

increase thyroid cell size, number and rate of secretion of T3 and T4

T3 and T4 concentrations have a negative feedback effect on TSH release, both at anterior pituitary and hypothalamus
Prolactin
peptide

promotes lactation by breasts (inhibited by progesterone and estrogen)

hypothalamus inhibits release of prolactin
Posterior Pituitary
composed of support tissue for nerve endings extending from hypothalamus

1. oxytoxin
2. ADH

hormones synthesized in neural cell bodies of hypothalamus and transported down axons to posterior pituitary, where they are released into blood

small polypeptides
Oxytocin
small peptide

increase uterine contractions during pregnancy

causes milk to be ejected from breats
Antidiuretic hormone (ADH or vasopressin)
small peptide

causes collecting ducts of kidney to become permeable to water, reducing amount of urine and concentrating urine

since fluids are reabsorbed, blood pressure also increases

coffee and beer are ADH blockers that increase urine volume
Adrenal glands
located on top of kidneys

separated into adrenal cortex and adrenal medulla
Adrenal cortex
outside portion of gland

secretes only steroid hormones

1. mineral corticoids - affect electrolyte balance in blood stream (aldosterone)
2. glucocorticoids - increase blood glucose concentration and increase fat and protein metabolism (cortisol)
Aldosterone
steroid, mineral corticoid

acts in distal convoluted tubule and collecting duct

increase Na+ and Cl- reabsorption

increase K+ and H+ secretion

creates net gain in particles in plasma, which results in increase in blood pressure

same effect on sweat, salivary and intestine glands
cortisol
steroid, glucocorticoid

increases blood glucose levels by stimulating gluconeogenesis in liver (creation of glucose and glycogen, in liver, from amino acids, glycerol and or lactic acid)

degrades adipose tissue to fatty acids to be used for cellular energy

causes decreases in use of glucose by cells

causes degradation of nonhepatic proteins, decrease of nonhepatic amino acids and as a result increase in liver and plasma proteins and amino acids

stress hormone
Catecholamines
tyrsoine derivatives

synthesize in adrenal medulla

1. epinephrine (adrenaline)
2. norepinephrine (noradrenaline)

vasoconstrictors of most internal organs and skin

vasodilators of skeletal muscles

fight or flight response, stress hormones
Thyroid
1. T3
2. T4 (thyroxine)
3. calcitonin

located along the trachea just in front of larynx
T3 & T4
similar in effect

T3 (3 iodine atoms)
T4 (4 iodine atoms)

lipid soluble tyrosine derivatives

diffuse through lipid bilayer

act in nucleus of cells

increase basal metabolic rate (resting metabolic rate)

secretion is regulated by TSH
Calcitonin
large peptide

released by thyroid gland

decreases blood calcium by decreasing osteoclast activity and number

not necessary for calcium level control
Pancreas (islets of langerhans)
acts as endocrine and exocrine gland

peptides, released in blood

1. insulin
2. glucagon
Insulin
peptide, released by beta-cells of pancreas

released when blood levels of carbohydrates and proteins are high

affects carbohydrate, protein and dat metabolism

causes storage of carbohydrates as glycogen in liver and muscles, fat in adipose tissue and amino acids taken up by cells and made into proteins

net effect is to lower blood glucose levels

binds to membrane receptor and causes cascade reaction, which causes cells (except neurons in brain) to become permeable to glucose, amino acids and intracellular metabolic enzymes are activated and translation and transcription rates are effected

receptor is not glucose carrier
Glucagon
peptide, released by alpha-cells of pancreas

effects are opposite of insulin

stimulates glycogenolysis (breakdown of glycogen) and gluconeogenesis in liver

acts via second messenger system (cAMP)

high concentrations cause glucagon breakdown of adipose tissue, increasing fatty acid level in blood

net effect is to raise blood glucose levels
parathyroid
4 small parathyroid glands attached to back of thyroid

release parathyroid hormone (PTH)
parathyroid hormone (PTH)
peptide, increases blood calcium

increases osteocyte absorption of calcium and phosphate from bone

stimulates proliferation of osteoclasts

increases renal calcium reabsorption and renal phosphate excretion

increase calcium and phosphate uptake from gut by increasing renal production of steroid DOHCC (derived from vitamin D)

regulated by calcium ion plasma concentration

parathyroid glands shrink and grow accordingly
Non-steroid reproductive hormones
peptides

1. FSH
2. LH
3. HCG
Male gonads
testes
Seminiferous tubules
production of sperm

in testes
Spermatogonia
located in seminiferous tubules

arise from epithelial tissue to become spermatocytes, spermatids and then spermatozoa
FSH
stimulate sertoli cells, which surround and nurture spermatocyte and spematids
Testosterone
released by leydig cells, located in interstitium between tubules, when stimulated by LH

primary androgen (male sex hormone)

stimulates germ cells to become sperm

responsible for development of secondary sex characteristics (pubic hair, enlargement of larynx, growth of penis and seminal vesicles)
Spermatozoon
no cytoplasm

1. head (nuclear material and enzymes)
2. midpiece (mitochondria)
3. tail (locomotion)
Epididymus
location where spermatozoon matures
Vas deferens
upon ejaculation, path through which spematozoa are propelled
Urethra
site of urine spermatozoa excretion
Semen
complete mixture of spermatozoa and fluid that leaves penis upon ejaculation

composed of fluid from seminal vesicles, prostate and bulbourethral glands (Cowper's glands)
Zona pellucida
viscous substance secreted by granulosa cells around the egg
Estradiol
type of estrogen

upon stimulation by LH, theca cells secrete androgen which is converted estradiol by granulosa cells in presence of FSH and secreted into blood

steroid hormone, prepares uterine wall for pregnancy

inhibits LH secretion by anterior pituitary
Ovulation
bursting of follicle, releasing egg
luteal surge
prior to, estradiol level rise rapidly, causing a dramatic increase in LH secretion

results from positive feedback loop of rising estrogen levels which increase LH levels, which increase estrogen levels

causes the follicle to burst (ovulation), releasing the egg (secondary oocyte) into body cavity
Fallopian (uterine) tube or oviduct
where egg is swept into after ovulation, by fimbriae
Corpus luteum
remaining portion of follicle left behind after ovulation

secretes estradiol and progesterone throughout pregnancy, or in case of no pregnancy, for 2 weeks until corpus luteum degrades
Corpus albicans
degraded corpus luteum and 2 weeks

no pregnancy
6 steps of ovulation
1. primary oocyte within follicle
2. growing follicle consists of theca cells surrounding granulosa cells which surround the zona pellucida and oocyte
3. secondary (graffian) follicle
4. ovulation: follicle ruptures, releasing secondary oocyte
5. corpus luteum develops from remnants of follicle
6. corpus luteum degenerates to corpus albicans if not fertilization of egg
Menstrual cycle
repeats itself every 28 days after puberty, unless pregnancy occurs

several oocytes may begin ovulation process, but only one completes the development to ovulation

3 phases:
1. follicular phase
2. luteal phase
3. flow
follicular phase
begins with development of follicle and ends at ovulation
luteal phase
begins with ovulation and ends with degeneration of corpus luteum into corpus albicans
flow
shedding of uterine lining lasting ~5 days
ovum
once sperm nucleus enters cytoplasm of oocyte and cortical reaction occurs, occyte goes through second meiotic division to form an ovum and releases a second polar body
Fertilization
occurs when nuclei of ovum and sperm fuse to form zygote
cleavage
begins while zygote is still in fallopian tube

goes through various cycles of mitosis
Morula
when zygote comprises of 8 or more cells

embryo, at this stage, doesn't grow during cleavage

1st 8 cells are equivalent in size, shape and are totipotent
blastocyst
hollow fluid filled ball after 4 days of diving post morula phase

lodges in uterus

made up of embryonic stem cells
implantation
5th - 7th day after ovulation

blastocyst lodges in uterus

female is said to be pregnant
human chorionic gonadotropin (HCG)
peptide hormone

secreted by egg upon implantation

prevents degeneration of corpus luteum

maintains secretion of estrogen adn progesterone

in blood and urine of mother, sign of pregnancy
Placenta
formed from tissue of egg and mother

takes over job of hormone secretion

reaches full development by end of 1st trimester

begins secreting its own estrogen and progesterone while lowering its secretion of HCG
Determination
process where cell becomes committed to a specialized developmental path

determined to give rise to specific tissue early one, no longer stem cells
Differentiation
specialization that occurs at end of development forming a specialized tissue cell
gastrula
formation occurs in 2nd week after fertilization
gastrulation
process of gastrula formation

3 primary germ layers are formed:
1. ectoderm
2. mesoderm
3. endoderm
ectoderm
develope into outer coverings of body

outer layers of skin, nails, tooth enamel and into cells of nervous system and sense organs
mesoderm
everything between ectoderm and endoderm

between inner and outer covering of body

muscle, bone, etc
endoderm
develop into lining of digestive tract, liver and pancreas
neurula
3rd week gastrula forms neurula
neurulation
process of neurula formation

notochord (mesoderm) induces overlying ectoderm to thicken and form neural plate
notochord induction
made from mesoderm

induces ectoderm to thicken and form neural plate


eventually degenerates, while neural tube forms from neural plate to become spinal cord, brain and nervous system

induction occurs when one cell type affects the direction of differentiation of another cell type
Apoptosis
programmed cell death

part of normal development

essential for development of nervous system, operation of immune system and destruction of tissue between fingers and toes

damaged cells may undergo this process as well, failure to do may result in cancer

regulated by protein activity and not transcription or translation