Blood Pressure And The Kidneys

Question 1

What senses a change in the concentration of sodium in the ECF?

Answer 1

Atrial stretch receptors
Arterial baroreceptors
Afferent arteriole
NaCl delivery to DT

Question 2

What does decreases in stretch receptors, baroreceptors and sodium chloride delivery to the distal tubule lead to?

Answer 2

Decreases in blood volume and increased sodium absorption

Question 3

What is RAAS activated by?

Answer 3

Reduced renal perfusion or increased sympathetic activity

Question 4

What are the two stimuli for aldosterone secretion?

Answer 4

RAAS and increased plasma [K+]

Question 5

How does reduced renal perfusion lead to renin release?

Answer 5

Macula densa cells signal to the juxtaglomerular apparatus. Juxtaglomerular cells secrete renin

Question 6

What does renin do?

Answer 6

Angiotensinogen -> angiotensin I

Question 7

What catalyses angiotensin I-> angiotensin II?

Answer 7

ACE

Question 8

What are the effects of angiotensin II?

Answer 8

Increased thirst
Aldosterone secretion
Vasoconstriction

Question 9

Where is most sodium reabsorbed?

Answer 9

Proximal tubule

Question 10

What mediates sodium absorption?

Answer 10

Aldosterone

Question 11

What does sodium reabsorption do?

Answer 11

Increases plasma osmolarity

Question 12

What system controls plasma osmolarity?

Answer 12

ADH by pure water reabsorption

Question 13

What are the effects of aldosterone acting on the principal collecting duct tubules?

Answer 13

increasing sodium potassium ATPase and increased expression of ENaC channels

Question 14

What does aldosterone acting on the principal collecting duct cells result in?

Answer 14

Increased sodium reabsorption and increased potassium secretion

Question 15

What are the effects of aldosterone acting on intercalated cells of the collecting duct?

Answer 15

Increased hydrogen ATPase

Question 16

What does increased hydrogen ATPase result in?

Answer 16

Increased hydrogen secretion and increased HCO3- reabsorption

Question 17

What are the two defences against volume depletion?

Answer 17

RAAS and ADH

Question 18

What are the parameters for hypertension?

Answer 18

Systolic > 140mmHg

Diastolic > 90mmHg

Question 19

What is secondary hypertension?

Answer 19

When you know the cause

Question 20

What is essential hypertension?

Answer 20

When you dont know what’s causing it

Question 21

What is Liddles syndrome?

Answer 21

Rare, genetic gain of function mutation in epithelial sodium channels

Question 22

What are the symptoms of liddles syndrome?

Answer 22

Increase in:
Renal sodium retention
ECFV
BP

Low aldosterone and renin

Question 23

What is conns syndrome?

Answer 23

Primary hyperaldosteronism

Question 24

What is the cause of conns syndrome?

Answer 24

Adenoma of the adrenal cortex

Question 25

What are the symptoms of conns syndrome?

Answer 25

Increased:
Renal sodium retention
ECFV
BP

Decreased plasma [K+]

Low renin and aldosterone

Question 26

What is a renal artery stenosis?

Answer 26

Abnormal narrowing of the blood vessel

Question 27

What changes would you see in the non-stenotic kidney?

Answer 27

Reduced renin and RAAS but overall high renin and aldosterone

Question 28

What changes will you see in the stenotic kidney?

Answer 28

Increased renin -> increased aldosterone and vasoconstriction -> sodium retention and high blood pressure

Question 29

Why does renin increase in the stenotic kidney?

Answer 29

Drop in blood volume so more RAAS takes place

Question 30

What is Addison’s disease?

Answer 30

Progressive failure of the adrenal cortex

Question 31

What does Addison’s disease cause a lack of?

Answer 31

Cortisol and aldosterone

Question 32

What happens in an adrenal crisis?

Answer 32

Hypotension, hypovolaemia, hypokalaemia, hyponatraemia