Adrenal Gland

Question 1

Where does the left and right adrenal vein drain into?

Answer 1

Left= renal vein Right- into inferior vena cava

Question 2

Compare the amount of arteries and vein that’s supplies or drains the adrenal gland

Answer 2

Has lots of arteries BUT only ONE vein

Question 3

Describe the micro anatomy of the adrenal gland and what molecules they secrete

Answer 3

Medulla- catecholamines Cortex- corticosteroids

Question 4

Describe the layers of the adrenal cortex and the hormones they make and secrete?

Answer 4

Outer- Zona glomerulosa; Aldosterone

Middle- Zona fasiculata: cortisol

Inner- Zona reticularis: sex hormones- androgens and oestrogen

Question 5

What is the importance of the Zona reticularis in animals? Compare with humans

Answer 5

Very important in producing sex hormones for animals, not so much humans as we have sex organs for that.

Question 6

What layer encapsulates the whole adrenal gland

Answer 6

Capsule

Question 7

Describe how hormones are secreted in adrenal glands

Answer 7

Hormones produced is transported into the many arteries which all empties into the adrenal vein

Question 8

What is precursor molecules for all corticosteroids and how many carbon molecules

Answer 8

Cholesterol- 27 carbon

Question 9

Describe the pathway for the formation of aldosterone from cholesterol

Answer 9

Cholesterol

Pregnenlone

Progesterone

11- Deoxycorticosterone

Corticosterone

Aldosterone

Question 10

What enzymes are involved in the reaction from pregnenlone to Aldosterone. List in ORDER

Answer 10

3 beta hydroxy steroid dehydrogenase

21 hydroxylase

11 hydroxylase

18 hydroxylase

Question 11

Describe the pathways for the formation of cortisol from cholesterol

Answer 11

Cholesterol

Pregnenlone

Progesterone

17-Hydroxy-progesterone

11-deoxycortisol

Cortisol

Question 12

List the enzymes involved in formation of cortisol from progesterone in ORDER

Answer 12

17 hydroxylase 21 hydroxylase 11 hydroxylase

Question 13

Where is the significance of this tightly controlled reaction requiring different enzymes.

Answer 13

Any small change in enzyme structure will have a massive impact on the pathway and hence on the body.

Question 14

What is the function of aldosterone?

Answer 14

Control Blood pressure by reabsorbing sodium ions in DCT and renal collecting duct

Secret potassium and hydrogen ion in DCT and collecting duct

Question 15

What other organs does aldosterone affect in reabsorption of sodium ions

Answer 15

Sweat glands, colon, gastric glands

Question 16

Describe what happens when aldosterone reaches DCT

Answer 16

Enters renal cells and act as a transcription factor

Cell release sodium ion transporter to membrane

Sodium ions reabsorbed back into kidney and enters blood through sodium potassium pump; water follows sodium to increase BP.

K+ and H+ secreted

Question 17

What enzyme is released when BP falls, what cells releases this?

Answer 17

Renin; by Juxtaglomerular apparatus

Question 18

Explain the process of what causes renin release

Answer 18

Decreased renal perfusion pressure due to low BP Increased renal sympathetic activity (direct to JGA cell) Decreased Na+ load to top of loop of Henle

Question 19

Explain the process of how renin causes aldosterone release?

Answer 19

Renin from kidney binds to Angiotensinogen from liver Angiotensin 1 is made Angiotensin 1 reacts with ACE to make angiotensin 2 Angiotensin 2 reaches Zona glomerulosa Activate the enzymes responsible for synthesis of aldosterone

Question 20

How is cortisol regulated

Answer 20

Mainly ACTH

Some AVP

Question 21

What are the physiological effects of cortisol

Answer 21

• Hepatic gluconeogenesis
• Fat metabolism
• Increased vascular permeability
• Immune suppression
• Peripheral protein catabolism
• Increased blood glucose concentration
• Excretion of water load

Question 22

What’s the effect of ACTH on the adrenal cortex Zona fasiculata

Answer 22

Activate the following enzymes Side chain cleavage 3 hydroxysteroid dehydrogenase 17 hydroxylase 21 hydroxylase 11 hydroxylase

Question 23

Describe how cortisol is released during the day

Answer 23

Diurnal rhythm by following the circadian rhythm Once at 8am and 4pm

Question 24

What is addison’s disease

Answer 24

Primary adrenal failure; Hence aldosterone and cortisol deficiency

Question 25

What are the potential causes of Addison’s disease

Answer 25

TB- forming GRANULOMA in adrenal cortex Autoimmune diseases- destroy cortex

Question 26

What are the signs and symptoms of Addison’s disease?

Answer 26

Increased pigmentation * Low BP; * weakness and weight loss * Constipation, * diarrhoea vomiting * Hyponatraemia * Fever * Syncope * Autoimmune vitiligo may coexist

Question 27

Explain why patient with Addison’s disease present with increased pigmentation ?

Answer 27

Pituitary still makes and secrete ACTH; A precursor of ACTH is POM-C. Another product of POM-C is MSH(melanin stimulating hormone) Too much MSH and melanin produced

Question 28

What are the urgent treatments of Addisonian crises

Answer 28

Dextrose- to prevent hypoglycaemia Hydrocortisone- a glucorcoticoid

Question 29

What is Cushing’s Syndrome?

Answer 29

Too much cortisol

Question 30

What are the potential causes of Cushing’s syndrome?

Answer 30

Tumour in pituitary- excess ACTH Tumour in adrenal- too much cortisol Taking steroid by mouth Ectopic ACTH due to lung cancer, heterotopia?

Question 31

What are the signs and symptoms of Cushing’s syndrome?

Answer 31

Easy bruising, * stretch marks- less protein made * Weight gain * Moon cheeks * Hyperglycaemia- Diabetes, high BP * Poor wound healing * Moon face * Osteoporosis * Proximal myopathy

Question 32

Name the catecholamines and they’re percentage in blood?

Answer 32

Adrenaline - 80% Noradrenaline- 20%

Question 33

What is the adrenal medulla derived from?

Answer 33

Ectodermal neural crest

Question 34

Where are catecholamines stored in adrenal medulla and to what stimulus are they released

Answer 34

Stored in cytoplasmic granules Released in response to ACh from preganglionic sympathetic neurones

Question 35

What is the precursor for adrenaline and NA

Answer 35

Tyrosine

Question 36

Outline the pathway for the formation of adrenaline from tyrosine?

Answer 36

Tyrosine- DOPA- Dopamine- Noradenaline- adrenaline

Question 37

What’s the effect of catecholamines in the body

Answer 37

1. Tachycardia, 2. sweating 3. increased blood glucose, 4. alertness, 5. vasoconstriction 6. Fight/flight response

Question 38

What two enzymes degrade the catecholamines?

Answer 38

Monoamine oxidase (MOA-O) Catechol-O-methyl transferase (COM-T)

Question 39

How does catecholamines travel through the blood?

Answer 39

Bind to albumin

Question 40

What investigations are used in diagnosis of Addison’s disease?

Answer 40

* HIgh K+, Low Na+ levels * High ACTH, MSH levels * Cortisol directly measured early in morning * Short synACTHen given and cortisol checked 30 min later to see if there’s a rise. If there is none then it’s Addison.

Question 41

Compare the speed and power of cortisol and adrenaline in increasing glucose levels.

Answer 41

Adrenaline - acts extremely quicker (very fast) than cortisol. Hence used when blood glucose levels falls dangerously low acutely Cortisol- slower acting but much more powerful in its effects. Can be used to gradually increase glucose levels for chronic conditions