endocrine

Question 1

what are the properties of a hormone

Answer 1

cell to cell communication molecules
binding to target receptor initiate cellular response
communication eventually terminated
half life

Question 2

what are the chemical classes of hormones

Answer 2

peptide/protein
steroid
amine

Question 3

peptide/protein hormones

Answer 3

made in endocrine cells all over body
made in advance and stored in vesicles for release
preprohormone-prohormone-hormone

• initially made as a large, inactive preprohormone; includes one or more copies of the final hormone
• series of post-translational modification converts it
• online final hormone in vesicle is active

release into ECF via exocytosis, then diffuses from ECF to blood (carried away in solution)
short half life (sec-min)
lipophobic - binds membrane receptors (activates 2nd messenger systems)

response usually involves altered activity of target proteins

Question 4

steroid hormones

Answer 4

made from cholesterol
only made in adrenal cortex, kidney, skin, gonads, placenta
final hormone is lipophilic so cannot be stored (will just diffuse out)
made on demand from lipophobic precursors that may be stored in intracellular compartments

released by simple diffusion into blood - transported bound to carrier proteins that bring them to target
longer half life (hours)

1. intracellular response - slow genomic response = modulation/regulation of gene activity. change in gene expression
2. membrane receptors - fast non-genomic response

Question 5

Smooth endoplasmic reticulum

Answer 5

contain enzymes requires for steroid sythesis
lipid and lipid like storage

Question 6

amine hormones

Answer 6

made in the pineal gland, adrenal medulla, thyroid
mostly derived from tyrosine

thyroid hormones, catecholamines

Question 7

thyroid hormones

Answer 7

amine
characteristics similar to those of steroid hormones

lipophilic, made on demand from lipophobic precursors stored in thyroid, requires carrier proteins, long half life, genomic responses

Question 8

catecholamine

Answer 8

amine
neurohormone

lipophobic, stored for release, short half life, change activity or target protein

Question 9

gland

Answer 9

collection of secretory cells

Question 10

exocrine

Answer 10

substance leaving the body
sweat

Question 11

endocrine

Answer 11

going into the bloodstream - inside the body

Question 12

alpha cell

Answer 12

secrete glucagon

Question 13

beta cell

Answer 13

secretes insulin

Question 14

what cellular processes could hormones regulate

Answer 14

rate of enzymatic rxns (speed/slow down)
transport of ions or molecules across cell membranes
gene expression and protein synthesis

Question 15

posterior pituitary

Answer 15

neural tissue
secretes two neurohormones (vasopressin and oxytocin)

Question 16

anterior pituitary

Answer 16

endocrine tissue secreting six true hormones synthesizes by endocrine tissue

Question 17

what is release of hormones from anterior pituitary controlled by

Answer 17

neurohormones from the hypothalamus

Question 18

how does the posterior pituitary glad secrete neurohormones

Answer 18

1. neurohormone is made and packages in the cell body of the neuron
2. vesicles are transported down the cell
3. vesicles containing neurohormone are stored in posterior pituitary
4. neurohormones are released into the blood

Question 19

how does the anterior pituitary release hormones

Answer 19

1. hypothalamic neurons synthesize neurohormones and release them into capillaries of the portal vein system
2. portal veins carry the neurohormones directly to the anterior pituitary, where they act on the endocrine cells
3. endocrine cells release their peptide hormones into the second set of capillaries for distribution to the rest of the body

Question 20

portal circulatory system

Answer 20

specialized modification where two sets of capillaries are connected in series by a set of small veins

Question 21

parathyroid hormone endocrine reflex loop

Answer 21

stimulus: low plasma [Ca2+]
integrating center: parathyroid cell (behind thyroid gland, moniters plasma calicum)
output signal: parathyroid hormone will be release to its targets
target: bone (has calcium) and kidney (filters calcium)
response: increase bone reabsorption, increase kidney reabsorption of calcium, production of calctriol leads to increased intestinal absorption of calcium

increased plasma calcium

Question 22

insulin endocrine reflex loop for eating a meal

Answer 22

stimulus: stretch receptor in digestive tract
sensory neuron brings to integrating center CNS then the efferent neuron
integrating center: pancreas
beta cells release insulin (peptide hormone)
target cell: target tissues
tissue response: increase glucose uptake and utilization
systemic response: decrease blood glucose

Question 23

insulin endocrine reflex loop for increase of blood glucose

Answer 23

integrating center: pancreas
beta cells release insulin (peptide hormone)
target cell: target tissues
tissue response: increase glucose uptake and utilization
systemic response: decrease blood glucose

Question 24

insulin endocrine reflex loop for increase of glucose in lumen

Answer 24

glucose in lumen
endocrine cells i small intestine
GLP-1

integrating center: pancreas
beta cells release insulin (peptide hormone)
target cell: target tissues
tissue response: increase glucose uptake and utilization
systemic response: decrease blood glucose

Question 25

modulations of cell responses

Answer 25

adjusting the number of receptors cells can adjust their sensitivity to hormone in response to changes in hormone concentration

Question 26

up regulation

Answer 26

increase receptor number in response to low hormone concentration try to maintain response despite low hormone concentration occurs when the body cannot synthesize enough of a hormone

Question 27

down regulation

Answer 27

decrease receptor number in response to sustain increase in hormone need to turn down the hormone since theres too much usually involves endocytosis of membrane receptors

Question 28

tropic hormone

Answer 28

control the secretion of another hormone

Question 29

trophic hormone

Answer 29

hormone causing something else to grow

Question 30

give an example of a tropic hormone

Answer 30

thyrotropin releasing hormone releases from the hypothalamus causes release of thyrotropin (thyroid stimulating hormone; TSH) from anterior pituitary causes release of thyroid hormones from thyroid

Question 31

synergism

Answer 31

two hormones act together to have a greater effect cells and tissues can be under the influence of multiple hormones at any given time, it is not always predictable functional overlap of hormones

Question 32

permissiveness

Answer 32

for a hormone to do their job they need the presence of another hormone if hormone A can't produce its full effect without the presence or hormone B, then B is permissive for A

Question 33

functional antagonists

Answer 33

hormones with opposite actions

Question 34

ligand

Answer 34

chemical molecule that binds to a receptor

Question 35

agonist

Answer 35

a ligand that binds to a receptor and enhances its activity may have the opposite effect in a different tissue

Question 36

antagonist

Answer 36

a ligand that binds to a receptor and inhibits its activity

Question 37

what is target cell response determined by

Answer 37

receptor and intracellular signalling pathways NOT on the ligand

Question 38

specificity

Answer 38

receptors may show preference for a particular ligand or type of ligand very specific - bind to few ligands non-specific - able to bind to many different ligands (not at the same time)

Question 39

competition

Answer 39

multiple ligands may compete for the same receptor active site usually one ligand binds better than the other (higher affinity)

Question 40

competitive antagonist

Answer 40

same binding site on receptor as agonist or primary ligand can be overcome by an increase in agonist concentration max response can still be achieved

Question 41

non-competitive antagonist

Answer 41

different binding site on receptor (allosteric site) than agonist. changes the shape or bind to the same active site but cannot unbind, permanently taking receptor out of the equation, irreversible antagonist) cannot be overcome by increase in agonist concentration

Question 42

when is the dose response curve maximal and saturated

Answer 42

if agonist concentration is high enough