Biology Lecture 5: The Endocrine System

Front 1

exocrine glands

Back 1

release enzymes into external environment or into body cavities through ducts

Front 2

endocrine glands

Back 2

release hormones directly into body fluids

Front 3

endocrine system

Back 3

- take a longer time to produce effects
- effects are usually longer lasting
- released into general circulation and are therefore indirect

Front 4

Pancreas as part of exocrine and endocrine system

Back 4

- exocrine: releases digestive enzymes through pancreatic duct
- endocrine: releases insulin and glucagon into blood

Front 5

General Functions of the Endocrine system

Back 5

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

Front 6

Three types of hormones

Back 6

- peptide
-steroid
- tyrosine derivatives

Front 7

Production of peptide hormones

Back 7

- manufactured in ER typically as a preprohormones, which is cleaved into a prohormone and exported to the golgi
- golgi packages the hormone into vesicles and exports via exocytosis

Front 8

How peptide hormones work

Back 8

- water soluble, bind to extracellular receptors of the effector
- Once bound they can...
1. the receptor can act as an ion channel
2. activate intracellular secondary messenger system (cAMP, cGMP, calmodulin)

Front 9

Common peptide hormones

Back 9

1) the anterior (front) pituitary hormones: FSH, LH, ACTH, hGH, TSH, Prolactin
2) the posterior (back) pituitary hormones: ADH and oxytocin
3) the parathyroid hormone: PTH
4) the pancreatic hormones: glucagon and insulin
5) thyroid - calcitonin

Front 10

production of steroid hormones

Back 10

formed in the smooth ER and the mitochondria

Front 11

effect of steroid hormones

Back 11

- usually act at the transcription level
- diffuse into the nucleus through the plasma membrane
- slow onset and last for long time
- usually increase production of proteins

Front 12

Important steroid hormones

Back 12

1. glucocoricoids and mineral corticoids of the adrenal cortex: cortisol and aldosterone (ACAC)
2. gonadal hormones: estrogen, progesterone, testosterone (estrogen and progesterone also produced by placenta)

Front 13

"sterone"

Back 13

indicates a steroid hormones

Front 14

Characteristics of thyroid hormones

Back 14

lipid soluble
bind to receptors in the nucleus, which increases the duration of their effect by induced a latent period

Front 15

Role of thyroid hormones

Back 15

increase transcription of large number of genes in nearly all cells of the body

Front 16

Tyrosine derivatives (examples)

Back 16

1. thyroid hormones: T3 (triiodothryonine) and T4 (thryoxine) --> in negative feedback with TSH
2. catecholamines (adrenal medulla): epinephrine and norepinephrine (AMEN)

Front 17

characteristics of (nor)epinephrine

Back 17

water soluble, dissolve in blood
bind to receptors on target tissue
act through cAMP

Front 18

production of tyrosine derivatives

Back 18

formed by enzymes in the cytosol or on the rough ER

Front 19

Anterior Pituitary Hormones

Back 19

1. hGH
2. ACTH (Adrenocorticotropic hormone)
3. TSH (thyroid stimulating hormone)
4. FSH (follicle stimulating hormone)
5. LH (Luteinizing hormone)
6. Prolactin

**ALL ARE PEPTIDE HORMONES***

Front 20

Posterior Pituitary Hormones

Back 20

Oxytocin
ADH (anti-diuretic hormone, vasopressin)

Front 21

Adrenal Cortex Hormones

Back 21

1. Aldosterone
2. Cortisol

**BOTH ARE STEROID HORMONES**

Front 22

Adrenal Medulla Hormones

Back 22

Epinephrine
Norepinephrine

**BOTH ARE TYROSINE DERIVATIVES**

Front 23

Thryoid Hormones

Back 23

T3, T4
Calcitonin

Front 24

Parathyroid hormones

Back 24

PH (parathyroid hormone)

Front 25

Pancreatic Hormones

Back 25

Insulin
Glucagon

Front 26

Ovarian Hormones

Back 26

Estrogen
Progesterone

Front 27

Testes Hormones

Back 27

Testosterone

Front 28

Placenta Hormones

Back 28

HCG (human chorionic gonadotropin)

Front 29

Human Growth Hormone (hGH)

Back 29

- stimulates the growth of nearly all cells
- no specific target tissue
- stimulates growth by increasing episodes of mitosis, increasing cell size, increasing the rate of protein synthesis, mobilizing fat stores, increasing use of fatty acids and decreasing rates of glucose consumption
- peptide hormone
- anterior pituitary

Front 30

Adrenocorticotropic Hormone (ACTH)

Back 30

- stimulates adrenal cortex (to release glucocorticoids via cAMP)
- peptide hormone
- anterior pituitary
- stimulated by stress
-

Front 31

Thyroid Stimulating Hormone (TSH)

Back 31

- stimulates the release of T3 and T4 from the thyroid via cAMP
- peptide hormone
- anterior pituitary
- T3 and T4 have a negative feedback effect on TSH

Front 32

Prolactin

Back 32

- promotes lactation
- anterior pituitary
- inhibited by estrogen and progesterone prior to pregnancy
- peptide hormone

Front 33

Oxytocin

Back 33

- increases uterine contractions and causes milk to be ejected from breasts
- posterior pituitary
- peptide

Front 34

Antidiuretic Hormone (ADH)

Back 34

- causes collecting ducts of kidney to become permeable to water, increasing uptake of water and decreasing urine output
- increases blood pressure
- posterior pituitary

Front 35

Relationship between Hypothalamus and Posterior pituitary

Back 35

- hypothalamus synthesizes oxytocin and ADH in neural cell bodies.
- Sent down to posterior pituitary where they are released into the blood stream

Front 36

Relationship between Anterior Pituitary and Hypothalamus

Back 36

- hypothalamus releases stimulating/inhibitory hormones to the anterior pituitary
- carried by a specialized capillary bed down to the anterior pituitary

Front 37

Aldosterone

Back 37

- mineral corticoid secreted by the adrenal cortex
- acts on distal tubule of kidney
- increases Na+ and Cl- absorption and K+ and H+ secretion
- increases blood pressure
- steroid hormone

Front 38

Mineral corticoids

Back 38

- affect the electrolyte balance in the blood stream

Front 39

Glucocorticoids

Back 39

- increase blood glucose concentration and have a greater effect on fat and protein metabolism

Front 40

Cortisol

Back 40

- steroid hormone
- stress hormone
- increases blood glucose levels
- stimulates gluconeogenesis in the liver (creation of glucose from amino acids, glycerol and lactic acid)
- causes degradation of adipose tissue and non-hepatic proteins
- diminishes capacity of immune system to fight infection

Front 41

Catecholamines

Back 41

- tyrosine derivatives synthesized from adrenal medulla
- epinephrine and norepinephrine

Front 42

Epinephrine and norepinephrine

Back 42

- same effect as nervous system (fight or flight) but lasting effects
- considered stress hormones
- vasoconstrictors of internal organs and skin, but vasodilators to skeletal muscle

Front 43

T3 and T4 (thyroxine)

Back 43

- increases basal metabolic rate
- thyroid hormone
- lipid soluble tyrosine derivatives
- act inside the nucleus

Front 44

Calcitonin

Back 44

- slightly decreases blood calcium by decreasing osteoclast activity and number
- large peptide hormone
- thyroid hormone
- not essential for blood calcium control

Front 45

Insulin

Back 45

- secreted by beta-islet cells of the pancreas
- decreasing blood glucose levels
- glucose is stored as glycogen in liver and muscle cells
- fat is stored in adipose tissue
- amino acids are turned to proteins
- neurons do not use insulin
- all other cells: insulin binds to a receptor and allows cells to become permeable to glucose
- also increases permeability of amino acids, metabolic enzymes are activated and translation/transcription rates effected

Front 46

Glucagon

Back 46

- peptide hormone released from alpha-islet cells of the pancreas
- stimulates glycocenolysis (breakdown of glycogen to glucose) and gluconeogenesis in liver
- increases blood level of glucose
- acts via cAMP
-
-

Front 47

Parathyroid Hormone (PTH)

Back 47

- peptide hormone that increases blood calcium
- increases osteocyte absorption of calcium and phosphate from bone
- stimulates release of 1,25(OH), derived from vitamin D, which stimulates calcium uptake from intestine
- increases renal reabsorption of calcium and phosphate in kidney
- part of negative feedback system

Front 48

Follicle Stimulating Hormone (FSH)

Back 48

Growth of Follicles in female
Sperm production in male

Front 49

Luteinizing hormone (LH)

Back 49

causes ovulation
stimulates estrogen and testosterone secretion

Front 50

estrogen

Back 50

growth of mother sex organs
causes LH surge
*steroid

Front 51

testosterone

Back 51

secondary sex characteristics
closing of epiphyseal plates
*steroid

--> look at PCS notes

Front 52

Human Chorionic Gonadotropin (HCG)

Back 52

Stimulates corpus luteum to grow and release estrogen and progesterone

Front 53

Progesterone

Back 53

prepares and maintains uterus for pregnancy
*steroid

Front 54

estradiol

Back 54

a form of estrogen secreted by theca cells that prepares the uterine wall for pregnancy

Front 55

apoptosis

Back 55

- programmed cell death
- regulated by protein activity (not transcription or translation)
- proteins involved with process are present but inactive in a normal cell
- mitochondria play an important role in apoptosis in mammals