intro to endocrine

Question 1

what does endocrine system do?

Answer 1

regulate multiple organs to meet growth and reproduction demands

Question 2

what are the classic endocrine organs?

Answer 2

hypothalamus

pituitary

thyroid

parathyroid

adrenal

gonads

endocrine pancreas

placenta

Question 3

which orgnas make hormones but thats not their main function?

Answer 3

adipose

heart

liver

kidney

GI Tract

Question 4

which hormones are modified peripherally

Answer 4

angiotensin II, vitamin D

Question 5

what are the three categories of hormones?

Answer 5

protein

steroid

amines

Question 6

whats special about peptide hormones?

Answer 6

stored in secretory vesicles

water soluble

more than 100 aa, proteins

less than 100aa, peptides

Question 7

whats special about steroid hormones

Answer 7

made from cholesterol

lipid soluble

not stored

Question 8

where do amine hormones come from?

Answer 8

tyrosine

Question 9

how are peptide hormones made?

Answer 9

made from preprohormone

in ER this becomes prohormone

this is packed into vesicles

enzymes cleave this to form functional hormone

Question 10

what causes release of peptide hormone from secretory vesicles?

Answer 10

endocrine cell stimulus causes release of hormone

more intracellular Ca

increased cAMP and PkA

Question 11

where are steroid hormones made?

Answer 11

adrenal cortex
gonads
corpus luteum
placenta

Question 12

how are steroid hormones made?

Answer 12

from cholesterol

add or remove side chaines
hyroxylate or aromatize steroid nucleus

Question 13

what are the two groups of amine hormones?

Answer 13

catecholamines

and

thyroid hormones

Question 14

how are catecholamines made? how do they act

Answer 14

made in cytosol and secretory granules

act through cell membrane receptors

Question 15

how are thyroid hormones made? how do they act

Answer 15

made in thyroid , stored as thyroglobulin in follicles

act as nuclear receptors

Question 16

explain the neural mechanism of secretion

give an example

Answer 16

neural input to endocrine cell increases or decreases secretion

example: sympathetic preganglionic innervation of adrenal medulla: causes catecholamines to be released

Question 17

explain the feedback mechanism of secretion

Answer 17

most common

element of pathway feeds back on endocrine to change secretion rate

Question 18

explain positive feedback

Answer 18

hormonal action causes more hormone to be made

leads to explosive event, such as ovulation

Question 19

explain negative feedback

Answer 19

most common

hormone inhibits further secretion of hormone

gives stability by keeping a barrier to physiology

Question 20

what is long loop feedback

Answer 20

3rd tier feeds back to 1st and 2nd tier

Question 21

what is short loop feedback

Answer 21

2nd tier hormone feeds back to 1st tier

Question 22

what is ultra short loop feedback

Answer 22

gland inhibits its own secretion

Question 23

how is hypothalamus regulated?

Answer 23

by descending and ascending neuronal inputs

Question 24

what are the major inputs to regulate the hypothalamus, what do they do?

Answer 24

SCN: circadian rhythm on secretion of hypothalamic hormone release

Pineal: releases melatonin, which feedbacks to SCN regarding day and night

physiological stress influences hypothalamus

Question 25

what confers specificity to hormone actions?

Answer 25

hormone receptor complex

Question 26

responsiveness to target tissue is expressed as what?

Answer 26

dose response relationship concentration that produces 50% of maximal response is senitivity

Question 27

how can hormone responsiveness be changed?

Answer 27

change the # of receptors change the affiniy of receptors for the hormone

Question 28

when does upregulation happen and how?

Answer 28

when hormone levels are low increase the number of receptors decrease degradation of existing receptors activate receptors

Question 29

when doe downregulation happen and how?

Answer 29

too much hormone decrease receptor synthesis increase degradation of receptors inactivate receptors

Question 30

what hormones use AC as their effector? whats he secon messenger? second effector?

Answer 30

ACTH, LH, FSH, TSH, Glucagon 2nd mess: cAMP Secon effector: PKA

Question 31

what hormones use phospholipase C as their effector? whats he secon messenger? second effector?

Answer 31

GnRH, TRH, oxytocin 2nd messenger: IP3/DAG/Ca 2nd effector: PKC or calmodulin

Question 32

what are the 6 steps of steroid hormone action?

Answer 32

1. unbound hormons fuse into target cell only 2. receptors are in cytoplasm or nucleus 3. binds to DNA, repress or activate genes 4. activated genes make mRNA, goes to cytoplasm 5. translation produced new protein 6steroid hormones bind to receptors that use second messenger systems to create rapid cell responses

Question 33

what does guanalyl cyclase do

Answer 33

converts GTP to cGMP results in relaxation of vascular smooth muscle (NO)

Question 34

what do receptor tyrosine kinases do?

Answer 34

have tyrosine kinase activity phosphorylates downstream proteins

Question 35

what do tyrosine kinase associated receptors do?

Answer 35

associate non covalently to proteins that have kinase activity phosphorylates downstream proteins

Question 36

what is autocrine?

Answer 36

acts on itself

Question 37

what is paracrine

Answer 37

acts on cells near it

Question 38

what is endocrine

Answer 38

acts on cells through blood stream

Question 39

what is neuroendocrine

Answer 39

nerve acts on cells through blood stream