Lecture 21: Corticosteroid production and regulation

Question 1

What are steroid hormones derived from?

Answer 1

Enzymatic modification of cholesterol

Question 2

The enzymes which produce steroid hormones from cholesterol are located in which regions of a cell

Answer 2

The mitochondria and smooth endoplasmic reticulum

Question 3

What is the initial precursor to steroid hormones?

Answer 3

Cholesterol

Question 4

What is the anatomical feature that all steroid hormones share?

Answer 4

A typical (but not identical) ring structure

Question 5

All steroid hormones are lipid ____

Soluble or insoluble?

Answer 5

All steroid hormones are lipid soluble

Question 6

Describe the storage of steroid hormones?

Answer 6

They are not stored by synthesised and immediately released

Question 7

Steroid hormones are water _____

Soluble or insoluble

Answer 7

Steroid hormones are water soluble

Question 8

Describe how steroid hormones are transported in the blood vessels?

Answer 8

They must be bound to specific binding globulins in the blood as they are not soluble in water

Question 9

What is the name of the specific binding globulins that carry cortisol?

Answer 9

Corticosteroid binding globulin

Question 10

Why are steroid hormones able to pass freely through the membrane?

Answer 10

Because they are lipid soluble

Question 11

The adrenal glands are situated above which anatomical organ?

Answer 11

The kidneys

Question 12

Why is the adrenal glands yellow in colour?

Answer 12

Because it is high in cholesterol

Question 13

Which part of the adrenal gland is rich in blood and nerve supply?

Answer 13

The adrenal medulla (inner part)

Question 14

How many adrenal glands do we have?

Answer 14

2

One of top of each kidney

Question 15

What are the two key areas to the adrenal gland?

Answer 15

Adrenal cortex (outer)

Adrenal medulla (inner)

Question 16

Which part of the adrenal gland is subdivided into zones?

Answer 16

The adrenal cortex

Question 17

The adrenal medulla and cortex are histologically distinct and have different embryological origins.

What tissues does each descend from?

Answer 17

The adrenal medulla originates from neural crest cells

The adrenal cortex develops from the intermediate mesoderm

Question 18

Which arteries supply the adrenal glands?

Answer 18

Superior suprarenal arteries

Middle suprarenal artery

Inferior suprarenal artery

Question 19

Name these parts of the blood supply to the adrenal gland

Answer 19

Question 20

Name these parts of the adrenal gland

Answer 20

Question 21

Which layer of the adrenal gland receives blood first

Answer 21

Centrepetal blood flow

Blood reaches the outer surface of the gland before entering and supplying each layer

Question 22

Describe the venous drainage of the adrenal gland

Answer 22

At the centre of the gland, the blood flows into the medullary veins

The medullary veins emerge from the hilum before forming the suprarenal veins, which join the inferior vena cava on the right side and the left renal vein on the left.

Remember!!!

Right = suprarenal -> IVC

Left = Suprarenal -> Left renal vein -> IVC

Question 23

Name these parts of the venous drainage of the adrenal glands

Answer 23

Question 24

The adrenal glands have a rich nerve supply. These nerves are derived from?

Answer 24

The coeliac plexus and the thoracic splanhnic nerves

Question 25

The nerves supply which cells in the adrenal medulla

Answer 25

The chromaffin cells (the neurohormone cells that produce noradrenaline and adrenaline)

Question 26

Why is it important for the adrenal medulla to have a rich nerve supply?

Answer 26

The sympathetic nervous system innervates this area to produce adrenaline and noradrenaline

Question 27

Name the 3 zones that make up the adrenal cortex

Answer 27

1. Zona glomerulosa (outermost zone) 2. Zona fasciculata 3. Zona reticularis (innermost zone)

Question 28

Describe the zona glomerulosa layer

Answer 28

Outermost layer of the adrenal cortex Its cells are pale staining and organized into clusters that are separated by capillaries. Contains fewer lipids than other layers The cells of the zona glomerulosa produce mineralocorticoid hormones like aldosterone, which regulates salt and water balance.

Question 29

Describe the zona fasciculata layer

Answer 29

Thick middle layer of the adrenal cortex Its cells are large and are extensively vacuolated because of the presence of lipid droplets. The cells of this region are organized into parallel cords separated by straight capillaries Produce glucocorticoids like cortisol, which has metabolic effects such as the regulation of carbohydrate metabolism

Question 30

Describe the zona reticularis layer of the adrenal cortex

Answer 30

The innermost layer of the adrenal corte Cells in the zona reticularis stain deeply and are less vacuolated. The cells are arranged in a haphazard arrangement This region produces androgens, such as DHEA, which supplement sex hormones produced by the gonads.

Question 31

Where is the only source of androgen production in females?

Answer 31

The zona reticularis of the adrenal cortex

Question 32

Which nerves are located in the adrenal medulla

Answer 32

Splanchnic nerves

Question 33

Noradrenaline and adrenaline are produced in the adrenal _____ by _____ cells. These hormones are secreted in response to _____ stimulation.

Answer 33

Noradrenaline and adrenaline are produced in the adrenal **medulla** by **Chromaffin** cells. These hormones are secreted in response to **sympathetic** stimulation.