Hormones and Receptors Flashcards Preview

Endocrinology > Hormones and Receptors > Flashcards

Flashcards in Hormones and Receptors Deck (43):
1

Is the endocrine system ductless or does it contain ducts?

ductless

2

Are glands anatomically distinct?

Yes, but do form functional system

3

What does the anterior pituitary release to cause the adrenal cortex to make cortisol?

ACTH

4

By what three ways is specificity of signalling achieved?

- chemically distinct hormones
-specific receptors for each
-distinct distribution of receptors across target cells

5

Name the 3 main classes of hormones.

Glycoproteins and peptides
Steroids
Tyrosine and tryptophan derivatives

6

Which hormone class is most diverse?

glycoproteins and peptides

7

Give an example of the glycoproteins and peptides class

oxytocin or insulin

8

Give examples of steroids.

Cortisol, testosterone

9

Give examples of Tyrosine and tryptophan derivatives.

adrenaline, melatonin and thyroid hormones

10

Are amines, peptides and proteins hydrophilic or phobic, and are they transported freely or bound?

hydrophilic, freely

11

Are steroids hydrophilic or phobic, and are they transported freely or bound?

hydrophobic, bound to plasma proteins

12

Are steroids and thyroxine soluble or insoluble in plasma?

relatively insoluble

13

What is the function of carrier proteins?

-increase amount of hormone transported in blood
-prevent rapid excretion by preventing filtration at kidney

14

What act as a buffer and ensure free and bound hormones are in equilibrium?

carrier proteins

15

Is albumin a specific or general carrier protein?

general

16

What does albumin bind?

many steroids
thyroxine

17

What does transthyretin bind?

thyroxine
some steroids

18

Do peptides and proteins need carrier proteins and why?

no, are soluble in plasma

19

What type of hormones, free or bound, can cross the capillary wall?

only free

20

What does cortisol bind globulin bind to sometimes as well as cortisol?

aldosterone

21

What does thyroxine binding globulin bind to?

T4 (thyroxine) as well as some triiodothyronine (T3)

22

What does sex steroid binding globulin (SSBG) bind to mostly?

testosterone and estradiol

23

What buffer surges in hormone?

carrier proteins

24

What is the primary determinant of plasma secretion?

rate of secretion

25

What 3 things is rate of secretion subject to?

- negative feedback control
- neuroendocrine (sudden bursts of secretion in response to stimulus eg stress)
-diurnal rhythm

26

Does rate of elimination contribute to plasma concentration?

Yes

27

How does rate of elimination generally occur?

By liver metabolism and kidney excretion

28

How long does amine elimination take?

seconds

29

How long does protein/peptide elimination take?

minutes

30

How long does steroid elimination take?

hours - days

31

What are the 3 main types of hormone RECEPTOR?

- G protein coupled
- receptor kinases
-nuclear receptors

32

What is the receptor for insulin an example of?

receptor kinases

33

Which classes are cell surface receptors?

G protein coupled and receptor kinases (nuclear receptors are intracellular)

34

What are G protein coupled receptors activated by?

amines and some proteins/peptides

35

What are receptor kinase receptors activated by?

proteins/peptides

36

How many classes are there of nuclear receptors?

3 (1, 2 and hybrid)

37

What activates class 1 nuclear receptors?

steroid hormones

38

Where are class 1 nuclear receptors when activated and when not?

no activated - cytoplasm, bound to heat shock proteins
activated- nucleus

39

Where are class 2 nuclear receptors?

nucleus mostly

40

What activates class 2?

mainly lipids

41

What activates the hybrid class?

thyroid hormone

42

What class is the hybrid class similar to in function?

class 1

43

What must the ligands be to diffuse across the membrane in nuclear receptors?

lipophilic