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Flashcards in exam 2b Deck (78)
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1
Q

Describe the adrenal glands.

A

Small, triangular positioned above kidneys.

2
Q

How much does each adrenal gland weigh?

A

4-6 g in adult

3
Q

How much of adrenal gland does outer cortex occupy?

A

80-90%

4
Q

What are the five layers of the adrenal gland?

A

From inside, medulla, zona reticularis, zona fasciculate, zona glomerulosa, capsule

5
Q

What hormones does medulla secrete?

A

Epinephrine and norepinephrine

6
Q

Name of cells in medulla?

A

Chromaffin cells and ganglion cells

7
Q

What blood vessels do we see in medulla histology?

A

Medullary veins

8
Q

What do zona reticularis and zona fasciculata secrete?

A

Glucocorticoids and gonadocorticoids

9
Q

What does zona glomerulosa secrete?

A

Mineralo-corticoids

10
Q

How is the adrenal medulla part of the CNS?

A

It is a modified sympathetic ganglion with postganglionic cells, but no axons, that is specialized to secrete catecholamines from chromaffin cells.

11
Q

Catecholamines?

A

Epinephrine and norepinephrine

12
Q

Synthesis of catecholamines cycle

A

Start with tyrosine tyrosine hydroxylase in cytoplasm dihydroxyphenylalanine (Dopa) aromatic L-amino acid decarboxylase in cytoplasm dopamine dopamine beta-hydroxylase in granule norepinephrine phenylethanolamine N-methyltransferase in cytoplasm epinephrine enters granule

13
Q

What are the major actions of epinephrine?

A

Stress/arousal response, metabolic action and cardiovascular action

14
Q

How do catecholamines affect sugar metabolism?

A

Inhibit insulin. Stimulate glucagon.

15
Q

How does stimulation of glucagon affect glucose metabolism?

A

In adipose tissue, stimulates lypolysis, which increases free fatty acids. In liver, stimulates keto-genesis, which increases ketones, stimulates glycogenolysis and gluconeogenesis, which upregulate glucose. Muscle undergoes glycogenolysis and increases lactate, which liver uses to make glucose.

16
Q

How do epinephrine levels react to hyperglycemia induced by insulin?

A

Rise 50 fold in normal human subjects.

17
Q

How do catecholamines react to swimming at 37, 33 and 21 degrees Celsius?

A

At 37 degrees, levels of epi and norepi are the lowest, reaching peak at about 60 minutes. At 33 degrees, second lowest. At 21, highest, due to stress of cold temperature. Thermogenesis.

18
Q

Describe beta-adrenergic receptor

A

G protein coupled 7TM domain receptor with ligand binding region buried in lipid bilayer. N terminus outside. C terminus in cytosol.

19
Q

Epinephrine signaling cascade

A

epinephrine to adenylyl cyclase, cAMP, PKA, enzyme activated, product

20
Q

Adrenergic receptors: what G protein do alpha 1 and M1 receptors couple with?

A

Gq

21
Q

What does Gq stimulate?

A

phospholipase C

22
Q

What does phospholipase C bind?

A

PIP2 in plasma membrane, which activates IP3/DAG pathway

23
Q

What does DAG activate?

A

protein kinase C

24
Q

What does IP3 do?

A

upregulates cytosolic calcium from endoplasmic reticulum.

25
Q

What does Ca2+ do in IP3/DAG pathway?

A

binds calmodulin, which activates a protein kinase

26
Q

Gq pathway?

A

phospholipase C / PIP2 / IP3/DAG pathway / IP3 upregulates calcium in cytosol / DAG activates protein kinase C / calcium binds calmodulin which activates protein kinase

27
Q

What G protein do alpha2, M2 and DA2 couple with?

A

Gi

28
Q

Gi pathway?

A

inhibit adenylyl cyclase, inhibit cAMP, inhibit PKA

29
Q

What G protein do beta1, beta2, beta3 and DA1 couple with?

A

Gs

30
Q

Gs pathway?

A

stimulate adenylyl cyclase, upregulate cAMP, activate PKA

31
Q

Functions of alpha receptor (6)

A

vasoconstriction, iris dilatation, intestinal relaxation, intestinal sphincter contraction, pilomotor contraction, bladder sphincter contraction

32
Q

Functions of beta receptors

A

beta1 – cardioacceleration, lipolysis, increased myocardial strength/ beta2 – vasodilatation, intestinal relaxation, uterus relaxation, bronchodilatation, calorigenesis, glycogenolysis and bladder wall relaxation

33
Q

General function of beta receptor

A

relaxation of tissue

34
Q

Which adrenergic receptor is dominant to epinephrine? Which is silent?

A

alpha receptor, which leads to smooth muscle contraction in physiological experiment. Beta receptor is silent.

35
Q

How can one reverse receptor dominance of catecholamines?

A

use an alpha receptor blocker to make alpha receptor silent and activate beta receptor, which relaxes smooth muscle

36
Q

Practolol

A

beta1 antagonist

37
Q

Butoxamine

A

beta2 antagonist

38
Q

Prenalterol

A

beta1 agonist

39
Q

Salbutamol

A

beta2 agonist

40
Q

Isoproterenol

A

beta adrenergic antagonist

41
Q

How does epinephrine compete against analogues alprenolol and isoproterenol in binding to liver receptors?

A

alprenolol and isoproterenol are more competitive

42
Q

How do beta blockers work with catecholamines?

A

if no blockers, full catecholamine stimulation of receptors. If beta blocker without agonism, no stimulation. If beta blocker with partial agonism, weak stimulation.

43
Q

Three types of adrenergic agonists

A

direct-acting, mixed-acting, indirect-acting

44
Q

What are the two types of direct-acting adrenergic agonists?

A

selective and non-selective

45
Q

Example of indirect-acting releasing agents

A

amphetamine, tyramine

46
Q

Example of indirect-acting uptake inhibitor

A

cocaine

47
Q

How do epi and norepi affect the isolated heart? What receptors mediate the responses?

A

they increase the force and rate of contraction of the isolated heart. Responses mediated by beta1 receptors.

48
Q

How does norepi affect blood vessels?

A

produces vasoconstriction in most if not all organs via alpha 1 receptors

49
Q

How does epi affect blood vessels?

A

dilates the blood vessels in skeletal muscle and the liver via beta2 receptors

50
Q

How does vasodilation by epi affect vasoconstriction elsewhere?

A

overbalances vasoconstriction by norepi and total peripheral resistance drops

51
Q

What happens when norepi is infused slowly in humans?

A

systolic and diastolic bp rise, which causes hypertension

52
Q

What does hypertension stimulate?

A

carotid and aortic baroreceptors, producing reflex bradycardia that overrides direct cardioacceleratory effect of norepi. Cardiac output thus falls.

53
Q

How does epi affect pulse pressure?

A

causes a widening of pulse pressure, but because baroreceptor stimulation is insufficient to obscure the direct effect of the hormone on the heart, cardiac rate, and output increase.

54
Q

2 ways to treat hypertension

A

lifestyle modifications and medication

55
Q

what is “not at goal bp”?

A

<130/80 mmHg for patients with diabetes or chronic kidney disease

56
Q

ACEI

A

angiotensin converting enzyme inhibitor

57
Q

ARB

A

angiotensin receptor blocker

58
Q

BB

A

beta-blocker

59
Q

CCB

A

calcium channel blocker

60
Q

Potential sites of action for antihypertensive drugs

A

CNS, heart, blood vessels, kidney

61
Q

Antihypertensive drugs for CNS

A

beta blockers, alpha2 agonists

62
Q

Antihypertensive drugs fro heart

A

beta blockers

63
Q

Antihypertensive drugs for blood vessels

A

alpha1 receptor blockers, calcium channel blockers, vasodilators, AT1 receptor antagonists, ACE inhibitors

64
Q

Antihypertensive drugs for kidneys

A

diuretics, beta blockers, ACE inhibitors

65
Q

Concept of receptor desensitization

A

at high concentration of hormone the physiological response may be lower than at lower concentration

66
Q

How can desensitization be achieved?

A

by modification of receptor to decrease optimal response (phosphorylation)

67
Q

How can receptor number be decreased?

A

internalization via endocytosis

68
Q

What does p53 respond to?

A

DNA damage, cell cycle abnormalities, hypoxia

69
Q

What does p53 lead to?

A

cell cycle arrest or apoptosis

70
Q

Cell cycle arrest pathway

A

cell cycle arrest/DNA repair/cell cycle restart/cellular and genetic stability

71
Q

Apoptosis pathway

A

death and elimination of damaged cells/cellular and genetic stability

72
Q

Uses of beta-antagonists in clinical medicine

A

to decrease cardiac output to treat hypertension an congestive heart failure; to treat migraine headache and stage fright; to treat PTSD

73
Q

Use of beta agonist in clinical medicine

A

to dilate bronchi in asthma

74
Q

Use of natural catecholamine in clinical medicine

A

to increase bp and increase heart rate

75
Q

Use of epi in clinical medicine

A

to treat allergic reaction

76
Q

What is pheochromocytoma?

A

tumor of adrenal gland. Benign but secretes lots of catecholamines.

77
Q

Symptoms of pheochromocytoma?

A

high bp, tachycardia, palpitations, sweating, tremors, nervousness, weight loss and hyperglycemia

78
Q

Detection of pheochromocytoma?

A

measure levels of catecholamines in blood or degradation products in urine. CT scan for adrenal tumors.