Endocrinology (lec 20)

Question 1

Hormone definition?

Answer 1

product of endocrine gland,
released directly into bloodstream,
acts peripherally on distant target cell,
causes biological effect

Question 2

Endocrine signalling is?

Answer 2

hormone action on distant target cell

Question 3

Paracrine signalling is?

Answer 3

hormone action on adjacent cell

Question 4

Autocrine signalling?

Answer 4

hormone action on cell of origin

Question 5

Neuroendocrine signalling?

Answer 5

Neuron origin -> axon -> hormone -> bloodstream

Question 6

Classification of Hormones by? (5)

Answer 6

1) how made/from what
2) storage/secretion
3) transport thru blood
4) secretion trigger
5) action on target

Question 7

Peptide Hormones synthesis?

Answer 7

(majority of hormones)
AA (preprohormone) -> into ER ->
remove one peptide, ∆s to prohormone ->
into golgi -> packed in vesicle, cut into hormone ->
vesicle to endocrine cell

Question 8

Peptide Hormone release?

Answer 8

stim cAMP/Ca2+ -> vesicle moved to cell memb ->

cell memb lysed/excytosis

Question 9

Amine Hormones synthesis?

Answer 9

SNS activation ->
tyrosine ->
Catecholamines (Epi, NorEpi, Dop, Thyroid)

Question 10

Amine Hormone storage/release?

Answer 10

similar to peptide hormones

Question 11

Steroid Hormone synthesis?

Answer 11

from cholesterol ->

∆ to steroid in organ-specific enz rxn

Question 12

Steroid Hormone storage/release?

Answer 12

Not stored

Released immediately

Question 13

Hormones soluble in plasma?

Answer 13

(hydrophyllic -> transports dissolved in blood)

Catecholamines and peptide

Question 14

Hormones insoluble in plasma?

Answer 14

(hydrophobic -> transport bound to proteins in blood)

Thyroid and steroid

Question 15

Binding Protein purpose?

Answer 15

1) ↑ hormone 1/2 life in plasma
2) hormone reserve supply
3) keeps hormones inactive while in blood
4) maintain hormone turnover rate

Question 16

Hydrophillic hormone action?

Answer 16

binds target cell memb receptor/channel

Question 17

Hydrophobic hormone action?

Answer 17

Steroid diffuse into cytosol -> bind to receptor in cytosol or move right into nucleus and bind receptor there

Question 18

Peripheral Conversion of hormones?

Answer 18

Nonsteroidgenic cell can take hormone of one type and convert it into hormone of different type

Question 19

Humoral secretion?

Answer 19

[blood element] ∆s -> endocrine gland detects and responds

Question 20

Neural secretion?

Answer 20

fright/stress stim CNS -> endocrine gland ->

hormone release -> physio response

Question 21

Hormonal secretion?

Answer 21

∆ in body -> hormone 1 into X -> 2 into Y -> 3 into Z -> physio response

Question 22

[Free/Active Hormone] depends on?

Answer 22

1) secretion
2) inactivation/excretion
3) plasma protein binding
4) activation/conversion rate

Question 23

Dose-Response Sensitivity is?

Answer 23

[Hormone] needed to produce 50% of max response

Question 24

↓ Max Response due to?

Answer 24

↓ # of receptors

↓ # of target cells

Question 25

↓ Sensitivity due to?

Answer 25

↓ hormone-receptor affinity

↓ # of hormone-receptor