Endocrinology: Renin-angiotensin System

Question 1

What is the juxtaglomerular apparatus in the kidney composed of?

Answer 1

1. Juxtaglomerula cells of afferent arterioles
2. Macula densa (cells on ascending loop of Henle)

Question 2

What is the role of JGA?

Answer 2

Regulares renin secretion

Question 3

What determines the release of renin by the JGA ?

Answer 3

1. Decreased arterial blood pressure
2. Decreased Na+ levels in plasma

Question 4

What is the role of renin?

Answer 4

Renin cleaves angiotensinogen to form angiotensin 1

Question 5

Describes the pathway of renin synthesis

Answer 5

Preprorenin –> prorenin –> renin

Question 6

Where is angiotensinogen secreted from?

Answer 6

Angiotensinogen is secreted by the liver

Question 7

What increases angiotensinogen secretion?

Answer 7

1. Oestrogen
2. Glucocorticoids

Question 8

Describe the synthesis of angiotensin 2

Answer 8

Angiotensinogen –> angiotensin 1 (via Renin)
Angiotensin 1 –> Angiotensin 2 (via ACE)

Question 9

What is the function of angiotensin?

Answer 9

1. Vasoconstriction
2. Aldosterone secretion stimulation

Question 10

Where is ACE found?

Answer 10

1. Endothelial cells of the pulmonary capillaries
2. Brain
3. Glomeruli