Control Arterial pressure - long term

Question 1

Why can’t baroreceptors provide information about absolute blood pressure?

Answer 1

Relationship between pressure and baroreceptor action potential firing frequency is not fixed

Question 2

What does resetting the baroreflex allow?

Answer 2

High cardiac output to be maintained without a fall in heart rate due to systolic pressure

Question 3

What does hypertensive cause?

Answer 3

Sensitivity of baroreceptors is reduced

Question 4

What is the major role of the baroreflex?

Answer 4

Buffer short-term fluctuations

Question 5

How is blood pressure regulated in the long term?

Answer 5

Maintenance of a normal extracellular fluid volume

Question 6

How is ECF volume regulated?

Answer 6

Renal excretion of salt and water

Question 7

What happens if blood volume decreases?

Answer 7

MAP decreases

Question 8

What do cardiovascular mechanoreceptors control?

Answer 8

Angiotensin II
Aldosterone
Vasopressin
Natriuretic peptides

Question 9

What does the JGA comprise of?

Answer 9

Juxtaglomerular cells, mesangial cells and macula densa

Question 10

What is the role of the macula densa cells?

Answer 10

Detect sodium levels
secrete vasoactive agents that affect afferent arterioles

Question 11

What is the role of the juxtaglomerular cells?

Answer 11

Sense renal pressure changes - stretch receptors
Increases renin secretion
Depend on paracrine signalling from macula densa

Question 12

What receptors act on the juxtaglomerular cells of afferent arterioles?

Answer 12

beta 1 adrenoreceptors

Question 13

What factors stimulate renin release?

Answer 13

Low blood pressure
Increased sympathetic activity

Question 14

What is the enzyme that converts angiotensin 1 to angiotensin 2?

Answer 14

ACE - angiotensin converting enzyme

Question 15

What is the role of angiotensin II?

Answer 15

Increase blood pressure (MAP)
Stimulates sympathetic vasoconstriction
Increases thirst - increases secretion of vasopressin

Question 16

When is renal sympathetic nerve activity (RSNA) increased?

Answer 16

Arterial baroreceptors detect a fall in arterial pressure
Veno-arterial mechanoreceptors detect a fall in central blood volume

Question 17

What does increased RSNA cause?

Answer 17

Increases renin secretion
Salt and water retention by kidneys

Question 18

What does increased RSNA stimulate?

Answer 18

Afferent arteriole constriction
Reduced GFR
Adrenaline release from adrenal medulla - renin release

Question 19

What does renin release cause?

Answer 19

Noradrenaline release
Granular cells secretion
Vasoconstriction of afferent arterioles
Lower GFR
Macula densa cell secretion

Question 20

What does aldosterone stimulate?

Answer 20

Increases Na+ reabsorption in collecting ducts and distal tubule

Question 21

What does ADH stimulate?

Answer 21

Water retention by the kidneys

Question 22

What is ADH secretion enhanced by?

Answer 22

Angiotensin II
Reduced central blood volume and arterial pressure

Question 23

What are natriuretic peptides produced by?

Answer 23

Some atrial and ventricular myocytes in response to increased blood volume

Question 24

What do natriuretic peptides stimulate?

Answer 24

Na+ excretion
Vasodilation

Question 25

What are two types of natriuretic peptides?

Answer 25

Atrial natriuretic peptide (ANP)
Brain natriuretic peptide (BNP)

Question 26

How do natriuretic peptides enhance renal salt and water excretion?

Answer 26

Afferent arteriole dilation
inhibition of Na+ reabsorption
inhibition of renin and aldosterone secretion

Question 27

What happens in renal artery stenosis?

Answer 27

Blood supply decreased
Blood flow is decreased
less oxygen due to atherosclerosis

Question 28

What does renal artery stenosis cause?

Answer 28

Renin secretion -> hypotension