Unit 2 - Adrenal Medulla

Question 1

Describe the adrenal medulla and its relationship to the sympathetic nervous system.

Answer 1

It is a modified sympathetic ganglion that releases neurotransmitters

Question 2

What hormones are secreted by the adrenal medula?

Answer 2

norepinephrine and epinephrine

Question 3

What is the chemical nature of norepinephrine and epinephrine?

Answer 3

they are neurotransmitters (catecholamines)

Question 4

What is the main trigger for the release of epinephrine and norepinephrine?

Answer 4

emotional stress, biochemical stress, physical stress

Question 5

What cell releases medullary hormones?

Answer 5

chromaffin cells

Question 6

What stimulates the release of chromaffin?

Answer 6

acetylcholine binds to nicotinic receptors to stimulate their release

Question 7

What is the fight-or-flight response?

Answer 7

a short-term response to the stress that involves the co-activation of the adrenal medulla and the rest of the sympathetic nervous system

Question 8

What are some physiologic effects of the fight-or-flight response?

Answer 8

increase cardiac output, increase renin release, vasodilation of arterioles in skeletal muscle, generalized venoconstriction, relax bronchiolar smooth muscle, pupillary dilation, calorigensis, decreased insulin and increased glucagon

Question 9

Which property of target cells explains the wide variety of physiological actions of epinephrine and norepinephrine?

Answer 9

the differential expression of alpha and beta receptors in target tissues

Question 10

What is the main consequence for the stimulation of alpha 1 receptor?

Answer 10

smooth muscle contraction and increased sweating

Question 11

What is the main consequence for the stimulation of alpha 2 receptor?

Answer 11

inhibition of neurotransmitter and hormone release, decrease of insulin secretion

Question 12

What is the main consequence for the stimulation of beta 1 receptor?

Answer 12

increased cardiac output

Question 13

What is the main consequence for the stimulation of beta 2 receptor?

Answer 13

smooth muscle relaxation, glycogenolysis, gluconeogenesis, lipolysis, and increase in hormone secretion

Question 14

What systems are involved in the integrated response of an organism in stress?

Answer 14

somatic nervous system, sympathetic nervous system, and hypothalamic pituitary adrenal axis

Question 15

How is the somatic nervous system involved in the integrated response of an organism in stress

Answer 15

Stress signals are sent to the cortex, limbic system, and reticular formation to release norepinephrine to stimulate arousal, behavioral activation, and aggressiveness

Question 16

How is the sympathetic nervous system involved in the integrated response of an organism in stress

Answer 16

Sympathetic neurons are stimulated in the hypothalamus stimulate the spinal cord to tell the adrenal gland to release epinephrine to slow down visceral function and stimulate energy mobilization and redistribution, and cardiovascular responsitivity

Question 17

How is thehypothalamic pituitary adrenal axis involved in the integrated response of an organism in stress

Answer 17

Stress signals stimulate CRH neurons to stimulate the pituitary to release ACTH to stop everything but energy mobilization and redistribution, cardiovascular responsivity

Question 18

What is pheochromocytoma?

Answer 18

a catecholamine secreting tumor

Question 19

In what species are you most likely to see pheochromocytomas?

Answer 19

older dogs

Question 20

How are pheochromocytomas treated?

Answer 20

by tumor resection and drugs to control hypertension