Adrenal medulla

Question 1

Adrenal Medulla

Answer 1

• innermost part of adrenal gland

- consists of Chromaffin cells

Question 2

Chromaffin Granules

Answer 2

• EPI;NE
• ATP;ADP
• chromogranin A
• dopamine Β-hydroxylase
• Ca2+

Question 3

major sites of metabolism of EPI and NE

Answer 3

liver & kidney

Question 4

what enzymes act on EPI and NE at the liver and kidney during their metabolism

Answer 4

• catechol-O-methyl transferase (COMT)

- monoamine oxidase (MAO)

Question 5

inactive metabolites formed from the metabolism of EPI and NE

Answer 5

• vanillylmandelic acid (VMA)
• metanephrine (from EPI)
• normetanephrine (from NE)

Question 6

catecholamine receptors

Answer 6

adrenergic receptors

cell surface

Question 7

2 classes of adrenergic receptors

Answer 7

• α

- β

Question 8

subdivisions of α adrenergic receptors

Answer 8

α1

α2

Question 9

subdivisions of β adrenergic receptors

Answer 9

β 1

β 2

β 3

Question 10

primary mechanism of action: α1 receptor

Answer 10

↑ IP3 and Ca2+ ; DAG

Question 11

primary mechanism of action: α2 receptor

Answer 11

↓ cAMP

Question 12

primary mechanism of action: β1 receptor

Answer 12

↑ cAMP

Question 13

primary mechanism of action: Β2 receptor

Answer 13

↑ cAMP

Question 14

primary mechanism of action: Β3 receptor

Answer 14

↑ cAMP

Question 15

location of α1 adrenergic receptors

Answer 15

sympathetic postsynaptic nerve terminals

Question 16

location of α2 adrenergic receptors

Answer 16

sympathetic presynaptic nerve terminals

β cell of pancreatic islets

Question 17

location of β1 adrenergic receptors

Answer 17

heart

Question 18

location of β2 adrenergic receptors

Answer 18

liver

smooth muscle of vasculature

bronchioles

uterus

Question 19

location of β3 adrenergic receptors

Answer 19

liver

adipose tissue

Question 20

Examples of Action: α1 adrenergic receptor

Answer 20

↑ vascular smooth muscle constriction (vasoconstriction)

Question 21

Examples of Action: α2 adrenergic receptor

Answer 21

inhibit NE release

inhibits insulin release

Question 22

Examples of Action: β1 adrenergic receptor

Answer 22

↑ cardiac output

Question 23

Examples of Action: β2 adrenergic receptor

Answer 23

↑ hepatic glucose output

↓ contraction of blood vessels, bronchioles, uterus (vasodilation)

Question 24

Examples of Action: Β3 adrenergic receptor

Answer 24

↑ hepatic glucose output

↑ lipolysis

Question 25

Metabolic Effects of Catecholamines: Liver

Answer 25

↑ glycogenolysis & gluconeogenesis

Question 26

Metabolic Effects of Catecholamines: Adipose

Answer 26

- inhibits glucose uptake into adipose - ↑ lipolysis by ↑ activity of hormone-sensitive lipase - --catalyzing the breakdown of triglycerides to free fatty acids that are released into blood -fatty acids taken up by liver where they are oxidized to keto-acids

Question 27

Metabolic Effects of Catecholamines: Skeletal Muscle

Answer 27

↑ glycogenolysis ↓ glucose uptake

Question 28

Metabolic Effects of Catecholamines: Pancreas

Answer 28

↓ insulin secretion ---results in inhibition of insulin-stimulated uptake of glucose into adipose and skeletal muscle ↑ glucagon secretion ---↑ the stimulatory effects of glucagon

Question 29

Cardiovascular Effects of Catecholamines: Heart

Answer 29

EPI = ↑ heart rate, cardiac contraction/relaxation, conduction velocity

Question 30

Cardiovascular Effects of Catecholamines: Vascular

Answer 30

- EPI and NE = vasoconstriction at splanchnic, renal, cutaneous, and genital vascular beds - ---↑ blood pressure -EPI = vasodilation in liver and skeletal muscle vascular beds

Question 31

Other Effects of Catecholamines

Answer 31

- ↑ muscle relaxation (bladder, bronchial, GI) - sphincter contraction (GI, bladder) - pupil dilation - ↑ platelet aggregation - ↑ renin secretion (with ↑ ANGII)

Question 32

Pheochromocytoma

Answer 32

- adrenal chromatin cell tumor that produces and secretes large amounts of NE and EPI - secretion occurs in BURSTS - large ↑ in VMA urine levels (24 hour test)

Question 33

Symptoms of Pheochromocytoma

Answer 33

- severe hypertension (200/110) - headache - anxiety - sweating - palpitations - feel hot, but hands and feet are cold