Adrenal Medulla

Question 1

What 2 overarching cell types are found in the adrenal medulla?

Answer 1

1. chromaffin cells
2. paraganglia

Question 2

What are paraganglia?

Answer 2

small groups of nerve cells

Question 3

Two chromaffin cell types

Answer 3

epinephrine + norepinephrine

Question 4

_______ is essential for the development of the adrenal medulla.

Answer 4

neural crest

Question 5

Neural crest gives rise to ________ which derives the adrenal medulla.

Answer 5

adrenal blasterna

Question 6

Which hormone produced by adrenal medulla is primary? What percentage are each type?

Answer 6

epinephrine (primary - 80%)
norepinephrine (20%)

Question 7

Give the order of the synthesis for production of catecholamines.

Answer 7

Tyrosine –> Dopa –> Dopamine –> Norepinephrine –> Epinephrine

Question 8

(T/F) The production of norepinephrine can stop and does not have to continue and form into epinephrine.

Answer 8

True

Question 9

What enzyme converts Tyrosine into Dopa in the synthesis of catecholamines?

Answer 9

tyrosine hyroxylase

Question 10

What enzyme converts norepinephrine into epinephrine?

Answer 10

PNMT

Question 11

What is the rate-limiting step in catecholamine synthesis?

Answer 11

tyrosine hydroxylase (tyrosine –> dopa)

Question 12

What must be present to convert norepinephrine to epinephrine via PNMT?

Answer 12

cortisol

Question 13

(Preganglionic/postganglionic) neurons of the (dorsal/ventral/lateral) horn of the spinal cord activate chromaffin cells to “dump” NE and E by releasing ________.

Answer 13

preganglionic
lateral
acetylcholine

Question 14

_______ causes an increase in HR, while ________ causes an initial increase then decrease in HR.

Answer 14

epinephrine
norepinephrine

Question 15

Which catecholamine increases force of heart contraction? What two effects follow?

Answer 15

epinephrine
increase cardiac output + BP

Question 16

Describe the general effects that both epinephrine and norepinephrine have on the following systems:

1. respiratory
2. skeletal
3. metabolic

Answer 16

1. up RR and depth, dilate bronchioles
2. increase contraction strength
3. increase BG & FFAs, increase glycogenolysis/lipolysis, inhibit insulin

Question 17

Match which action of catecholamines is true or false.

1. dilate radial M of iris
2. decrease GI motility
3. decrease stomach sphincter contraction

Answer 17

1. false - constrict (dilates eye)
2. true
3. false - increase

Question 18

How do catecholamines affect glucose?

Answer 18

increase blood glucose
inhibit insulin directly

Question 19

What 5 target receptors do norepinephrine and epinephrine use?

Answer 19

ALL adrenergic:
Beta 1
Beta 2
Beta 3
Alpha 1
Alpha 2

Question 20

(T/F) Both norepinephrine and epinephrine can bind to adrenergic receptors but one may have a greater effect than the other.

Answer 20

True

Question 21

What two enzymes are responsible for the degradation of catecholamines?

Answer 21

MAO
COMT

Question 22

What is the main byproduct of catecholamine degradation? How is it removed from the body?

Answer 22

VMA (acid)
excreted in urine

Question 23

Term for chromaffin cell tumor

Answer 23

pheochromocytoma

Question 24

A pheochromocytoma leads to a(n) (excess/deficiency) of catecholamines.

Answer 24

excess

Question 25

List 4 symptoms of pheochromocytoma

Answer 25

1. hypertension
2. panting
3. tachycardia
4. muscle wasting

Question 26

An overproduction of catecholamines within and outside the adrenal medulla is a disorder called:

Answer 26

multiple endocrine neoplasia (MEN)

Question 27

(T/F) There is an autosomal recessive genetic link to Multiple Endocrine Neoplasia.

Answer 27

False - autosomal dominant

Question 28

(T/F) Multiple Endocrine Neoplasia is common in dogs but not cats.

Answer 28

False - neither is common