Endocrinology - Lecture 3

Question 1

What are the two divisions of the adrenal gland?

Answer 1

Medulla

Cortex

Question 2

Adrenal Medulla

Answer 2

Inner portion of the gland
Part of the sympathetic nervous system…it’s a modified sympathetic ganglion
Autonomic nervous system that controls fight or flight
Derived from neural crest cells

Question 3

Adrenal Cortex

Answer 3

Outer portion of the gland
Responds to hormones
Derived from mesothelial cells of the intermediate mesoderm

Question 4

What types of hormones are secreted by the adrenal medulla?

Answer 4

Catecholamines: epinephrine and norepinephrine

Question 5

T/F - The adrenal medulla is a gland in the sympathetic ganglion with no postsynaptic neurons with axons

Answer 5

True

Question 6

Why does the adrenal medulla secrete more epinephrine than norepinephrine?

Answer 6

It contains significant amounts of the enzyme phenyl-N-methyltransferase, which converts NE to E

Question 7

What are the divisions of the adrenal cortex?

Answer 7

Zona glomerulosa
Zona fasciculata
Zona reticularis

Question 8

Zona glomerulosa

Answer 8

Outermost layer of the adrenal cortex
Cells are arranged in clumps
Secretes Aldosterone

Question 9

Zona fasciculata

Answer 9

Middle layer of the adrenal cortex
Cells are arranged in long, parallel lines 
Secretes glucocorticoids (cortisol and corticosterone)

Question 10

Zona reticularis

Answer 10

Innermost layer of the adrenal cortex
Cells are arranged in a net-like or web orientation
Secretes sex steroids (DHEA, androstendione)

Question 11

Aldosterone

Answer 11

Mineralcorticoid produced by cells in the zona glomerulosa

Question 12

Aldosterone action

Answer 12

Stimulate Na and H2O retention in order to maintain blood volume and blood pressure

Question 13

What is the largest target tissue of aldosterone

Answer 13

Kidneys

Question 14

What regulates the secretion of aldosterone?

Answer 14

• The kidney secretes a hormone (renin) when blood pressure or Na blood levels are too low
• Stimulated by an increase in plasma K
• Stimulated by a decrease in plasma pH or an increase in plasma H+
• Stimulated by a drop in systemic blood pressure
• Inhibited by an increase in Na intake

Question 15

Glucocorticoids

Answer 15

Cortisol and corticosterone

Secreted by the cells of the zona fasciculata

Question 16

What is the major function of glucocorticoids

Answer 16

Increase metabolic fuel availability and use in tissues

Question 17

What effect does cortisol have on the body?

Answer 17

Increase gluconeogenesis in the liver
Increase proteolysis in muscles
Increase lipolysis
Decrease glucose uptake in muscle and fat
Decrease immune and inflammatory responses
Decrease growth and reproductive energy
Regulate blood pressure

Question 18

Androgens

Answer 18

Sex steroids secreted by the zona reticularis

Dehydroepiandrosterone (DHEA) and Androstenedione

Question 19

Dehydroepiandrosterone (DHEA)

Answer 19

A precursor of other sex steroids - so it can serve as a circulating reservoir in peripheral tissues containing steroidogenic enzymes
Relatively weak androgenic action

Question 20

Androstenediione

Answer 20

Synthesized by enzymatic conversion of DHEA
Stronger than DHEA
Provides a non-gonadal source of testosterone and estradiol - an important source of reproductive steroids prior to puberty and in postmenopausal women

Question 21

What do adrenal sex steroids do?

Answer 21

Regulate mood, libido, hair growth, erythropoiesis, and acne

Question 22

Why is the stress response important?

Answer 22

It is critical for maintenance of homeostasis and essential for survival
It allows the body to respond to things that are deviations from the “norm”

Question 23

What happens if a stress response persists after the stress is gone?

Answer 23

Adverse effects that can become damaging

Question 24

What adverse conditions can occur to chronic stress responses?

Answer 24

Cortisol will catabolize tissue, which can be rebuilt when stress is over. But if stress prolongs, it won’t rebuild and the body can be damaged
Cortisol has high anti-inflammatory and anti-immune effects. This conserves energy in the long term, but we want these things to work at some point.
Mobilization of metabolic fuels increases lipids in the blood, and along with increased blood pressure can lead to atherosclerosis, hypertension, and blood clots

Question 25

What evidence is there for an interaction between immune function and activation of the stress response?

Answer 25

- HSV + psychiatric illness --> increased recurrences and duration of outbreak - Influenze + family dysfunction --> increased frequency and severity of illness - Hep B + exams --> delayed antibody response to vaccine

Question 26

What is the CNS connection to the stress response?

Answer 26

A stress response is a response of the stress axis (Hypothalamus - ant pituitary - adrenal cortex) to a stressor that stimulates hypothalamic CRH neurons and inputs to the SNS

Question 27

What are the causes of a primary insufficiency leading to Addison's Disease

Answer 27

Disease A congenital disorder Autoimmune disorder

Question 28

What are the causes of a secondary insufficiency leading to Addinson's Disease?

Answer 28

Pituitary problem Glucocorticoid therapy - can use exogenous corticosteroids, which has feedback effects on CRH and ACTH which can impair a normal stress response

Question 29

What are symptoms of adrenal insufficiency (Addison's disease)

Answer 29

Low cortisol High ACTH Weakness, lethargy, and decreased appetite Low blood pressure Low glucose when fasting Hyperpigmentation due to lack of negative feedback control of POMC

Question 30

How do you treat adrenal insufficiency? (Addison's disease)

Answer 30

Exogenous glucocorticoids and/or dietary controls

Question 31

What causes Hypercortisolinemia (Cushing's disease)

Answer 31

Typically due to a pituitary tumor or administering too much exogenous glucocorticoid

Question 32

How do you treat Hypercortisolinemia?

Answer 32

Remove the tumor that's causing it

Question 33

What are symptoms of Hypercortisolinemia?

Answer 33

Excessive tissue catabolism (especially bone, skin, and muscle) Type II Diabetes-like symptoms (increased appetite and circulating glucose) Impaired immune functions Threat of hypertension

Question 34

What is the primary concern for dentists seeing patients with Hypercortisolinemia?

Answer 34

Impaired immune function after a procedure Hypertension Osteoperosis Increased bleeding