SCT II - Renal Humoral Regulation

Question 1

What is RAAS

Answer 1

Renin-Angiotensin-Aldosterone-System

Question 2

How is Angiotensin-II activated?

Answer 2

Angiotensinogen released in Liver

Renin (via kidneys) converts Angiotensinogen to Angiotensin-I

ACE (Angiotensin-converting-enzyme via lungs) converts Angiotensin-I to Angiotensin-II

Question 3

What stimulates Renin production in the kidney?

Answer 3

1. Low kidney perfusion
2. Low tubular [Na+]

Question 4

What is the function of Angiotensin-II?

Answer 4

Stimulates VASOCONSTRICTION
- Increasing TPR
- Increasing MAP

Stimulates Aldosterone release
Increasing [Na+] + [H2O] reabsorption
- Increases Plasma Volume
- Increases MAP

Question 5

What is the function of ADH/Vasopressin?

Answer 5

V1 Receptors
- Vasoconstriction
- TPR INC
- MAP INC

V2 RECEPTORS
- Water reabsorption
- Blood Volume INC
- MAP INC

Question 6

How is ANF (ANP) produced?

Answer 6

Atrial Natriuretic Factor (Peptide) is produced by the atria if there’s too much blood volume, causing it to stretch

Question 7

What is the function of ANF (ANP)?

Answer 7

Opposite of ADH (Vasopressin)

Increasing diuretics (urinating)
Stimulates VASODILATION
- TPR DEC
- MAP DEC
- Blood Volume DEC

Inhibits Aldosterone
- [Na+] & [H2O] reabsorption inhibited
- Urine amount increased

Question 8

Name all vasoconstrictor agents

Answer 8

1. Norepi
2. Epi (Large conc.)
3. Angiotensin II
4. ADH (Vasopressin)
5. Endothelin-1
6. Neuropeptide Y
7. TXA 2

Question 9

Name all vasodilator agents

Answer 9

1. Epi (Small conc.)
2. Adenosine
3. VIP
4. Badykinin
5. Prostanoids
6. Histamine
7. Serotonin (intact endothelium)
8. Acetylcholine (intact endothelium)
9. ANF
10. Substance P
11. Adrenomedullin

Question 10

What are the effects of norepi?

Answer 10

β-1 Receptors
Positive tropic effects

α-1 Receptors
Arterial Vasoconstriction

α-1 + α-2 Receptors
Venous Vasoconstriction

• All increase MAP through TPR & CO
• Reflex Bradycardia intervenes

Question 11

What is reflex bradycardia?

Answer 11

When the MAP increases due to Norepi, the HR decreases to combat too much BP. This happens via the Baroreceptor reflex.

Question 12

What is the relationship between SP and SV?

Answer 12

SP ~ SV

Question 13

What is the relationship between DP and TPR?

Answer 13

DP ~ TPR

Question 14

What are the effects of Epi at physiologic concentration (low)?

Answer 14

β-1 Receptors
Positive tropic effects

β-2 Receptors
Certain vascular vasodilation

Question 15

what are the effects of Epi at high concentration?

Answer 15

Saturate the β receptors and therefore bind to α receptors which overwrite β receptors.

Causing vasoconstriction?

Question 16

Where is VIP found? What is its function?

Answer 16

Vasodilator

Induces smooth muscle relaxation via Gs proteins

Found in:
- Salivary glands
- Pancreas
- GI tract

Question 17

Where is Bradykinin found? What is its function?

Answer 17

Vasodilator

• Increases blood vessel permeability
• Increases contraction of non-vascular smooth muscle AKA Bronchoconstriction

Brady = slow
Kinin = contraction

Question 18

How do vasoconstricting agents actually vasoconstrict?

Answer 18

1. Agent binds to endothelium
2. Endothelium cells release Endothelin
3. Endothelin contracts smooth muscle

Question 19

How do vasodilating agents actually vasodilate?

Answer 19

1. Agent binds to endothelium
2. Endothelium cells release NO & PGI2 (Prostacyclin)
3. Two products cause relaxation of smooth muscle

Question 20

What breaks down Bradykinin? And what’s so special about that enzyme?

Answer 20

ACE (Angiotensin-Converting-Enzyme)

Converts Angiotensin-I to Angiotensin-II (Active form)