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Question 1

What are the two types of stress axis’?

Answer 1

Sympathetic Adrenal Medullary (SAM) and Hypothalamic Pituitary Adrenal (HPA)

Question 2

Which pathway is immediately activated (within seconds) during stress and the peak response occurs minutes later?

Answer 2

SAM

Question 3

Which pathway has delayed onset (within minutes) and peaks within hours?

Answer 3

HPA

Question 4

How does the SAM axis operate?

Answer 4

Sympathetic nervous system stimulates the adrenal medulla to release catecholamines into the blood stream which triggers fight to flight response by increasing heart rate, dilating airways and redirecting blood flow to vital organs preparing for fight or flight

Question 5

What are the catecholamines released by the adrenal medulla during SAM axis activation

Answer 5

epinephrine and norepinephrine

Question 7

What is unique about the HPA and SAM axis?

Answer 7

There is bidirectional communication during activation and inactivation of the stress response because they share the adrenals.

Question 8

Give an example of communication between the HPA and SAM axis.

Answer 8

Epinephrine and Norepinephrine (catecholamines) can act as receptors on the hypothalamus, and influence the secretion of CRH (the key initiator of HPA axis response) which causes the anterior pituitary to release ACTH which acts on the Adrenal Cortex to release Glucorticoids (Cortisol) which can regulate the secretion of catecholamines from the adrenal medulla.