Adrenal and Pineal Microstructure

Question 1

What are the 2 parts of the adrenal gland?

Answer 1

cortex and medulla

Question 2

What does the cortex produce?

Answer 2

mineralocorticoids, glucocorticoids and androgens

Question 3

What does the medulla produce?

Answer 3

catecholamines (epinephrine and norepinephrine)

Question 4

What are the layers of the adrenal gland from outside to inside?

Answer 4

capsule, zona glomerulosa, zona fasciculata, zona reticularis and medulla

Question 5

What does zona glomerulosa produce?

Answer 5

steroid hormone and mineralocorticoid aldosterone

Question 6

How are the cells organized in the zona glomerulosa?

Answer 6

into lobules of cells surrounded by the CT

Question 7

What is the function of the zona glomerulosa?

Answer 7

secretes mineralocorticoids that regulate sodium and potassium homeostasis and water balance: main secretion aldosterone.

Question 8

What does the zona facsciculata produce?

Answer 8

cortisol steroid hormone

Question 9

How are the cells arranged in zona fasciculata?

Answer 9

Cells are arranged in columns with capillaries (fenestrated) lying in between the columns. Cells look frothy and pale staining.

Question 10

Why do the cells of the zona glomerulosa and fasciculata have a spongy look?

Answer 10

because they contain many lipid droplets

Question 11

What hormone controls the secretions of the adrenal cortex?

Answer 11

CRH (corticotropin releasing hormone) from the hypothalamus and ACTH from the anterior pituitary

Question 12

What are the functions of cortisol?

Answer 12

• Promotes normal carbohydrate metabolism
• stimulates glycogen synthesis in the liver.
• Stimulates mobilization of fats
• Suppresses inflammation
• Involved in resistance to stress

Question 13

What is produced by zona reticularis?

Answer 13

dehydroepiandrosterone (DHEA) steroid hormone

Question 14

What regulates synthesis and secretion of DHEA?

Answer 14

CRH (from hypothalamus) and ACTH (from anterior pituitary)

Question 15

Describe the histology of the zona reticularis

Answer 15

cells appear more dense in this area/stain more intensely, fewer lipid droplets than the other zones, and cells are arranged in bundles

Question 16

What 2 types of cells does the medulla contain?

Answer 16

Chromaffin cells and autonomic ganglion cells

Question 17

What are chromaffin cells?

Answer 17

Modified neurons (postganglionic sympathetic) of the medulla. There are 2 types, one that makes epinephrine and one that makes norepinephrine. Cells have many dense secretory granules. Don’t develop their own processes. Found near fenestrated capillaries.

Question 18

What stimulates a chromaffin cell?

Answer 18

ACh released from the preganglionic sympathetic neuron whose cell body lies in the lateral horn of spinal cord.

Question 19

What inhibits chromaffin cells from developing their own processes?

Answer 19

glucocorticoids (cortisol) made in the cortex.

Question 20

How are glucocorticoids transported to the chromaffin cells?

Answer 20

via the blood supply. Takes the route from the artery to vein that has no capillary beds in the cortex.

Question 21

What does the pineal gland develop from?

Answer 21

Neuroectoderm

Question 22

What does the pineal gland regulate?

Answer 22

is a photosensitive organ that regulates day/night cycles and circadian rhythm.

Question 23

What are the three cell/molecules of the pineal gland parenchyma?

Answer 23

1. pinealocytes
2. astorcytes (supprotive, glial-type cells)
3. corpora arancea (brain sand, precipitates of Ca and K)

Question 24

What are pinealocytes?

Answer 24

Large cells with pale nuclei and prominent nucleolus. Secretes the products of the pineal gland.

Question 25

What does the pineal gland produce?

Answer 25

Melatonin which comes from serotonin

Question 26

How does the pineal gland receive light information from the environment?

Answer 26

light from the retina is sent to the suprachiasmatic nucleus of the hypothalamus. Fibers then descend to the superior cervical ganglion and then post ganglionic fibers are sent back up to the pineal gland telling it to either produce more or less melatonin depending on the environment.

Question 27

When are melatonin levels high?

Answer 27

At night. Day light inhibits production of melatonin, so serum levels during the day drop.

Question 28

What is the rate limiting steop of melatonin formation?

Answer 28

serotonin-N-acetyltransferase

Question 29

What does the pineal gland regulate?

Answer 29

regulates reproductive functions by inhibiting steroidogenic activity of the gonads.
Role in adjusting to changes in day length
role in emotional response to change in length of day and temperature.