Control of Systemic Blood Pressure

Question 1

Which of the following do you think are effects of the baroreceptor reflex in response to a fall in blood pressure?

A. Adrenaline secretion
B. Arterial vasoconstriction
C. Increased secretion of vasopressin
D. Sodium retention
E. Splanchnic venoconstriction
F. Tachycardia and increased myocardial contractility

Answer 1

All of them.

A. Adrenaline secretion by the adrenal glands is stimulated by increased sympathetic activity.

B. Vasoconstriction of peripheral vessels is a result of sympathetic vasomotor activity.

C. Increased secretion of vasopressin occurs when the brain responds to a fall in the blood pressure.

D. Sodium retention occurs when increased sympathetic activity leads to renin secretion.

E. Increased sympathetic vasomotor activity also causes splanchnic venoconstriction.

F. Reduced vagal activity mediates tachycardia, together with adrenaline secretion this increases myocardial contractility.

Question 2

Regarding the sympathetic control of BP (true or false):

The single most important physiological regulator of vascular tone is sympathetic vasoconstriction

Answer 2

True

Question 3

Regarding the sympathetic control of BP (true or false):

The sympathetic fibres release adrenaline

Answer 3

False. The sympathetic fibres release noradrenaline.

Question 4

Regarding the sympathetic control of BP (true or false):

The transmitter release is quantal

Answer 4

True

Question 5

Regarding the sympathetic control of BP (true or false):

Arterioles are the most densely sympathetically innervated blood vessels

Answer 5

True

Question 6

Regarding hormonal control of blood pressure (true or false):

Adrenaline has both metabolic and cardiovascular effects

Answer 6

True

Question 7

Regarding hormonal control of blood pressure (true or false):

Vasopressin is synthesized in the kidney

Answer 7

False. Vasopressin is synthesized in the magnocellular neurons of supraoptic and paraventricular nuclei.

Question 8

Regarding hormonal control of blood pressure (true or false):

Angiotensin II production is mediated by renin and endothelial ACE

Answer 8

True

Question 9

Regarding hormonal control of blood pressure (true or false):

Angiotensin II is a direct vasoconstrictor

Answer 9

True

Question 10

Regarding hormonal control of blood pressure (true or false):

Natriuretic peptides increase the plasma volume

Answer 10

False. Natriuretic peptides reduce the plasma volume.

Question 11

Regarding baroreceptors (true or false):

Baroreceptors respond to hypoxic stimuli

Answer 11

False. Baroreceptors are stretch receptors.

Question 12

Regarding baroreceptors (true or false):

Baroreceptors have only dynamic sensitivity

Answer 12

False. Baroreceptors have static and dynamic sensitivity.

Question 13

Regarding baroreceptors (true or false):

The baroreceptor reflex provides short-term homeostasis of blood pressure

Answer 13

True

Question 14

Regarding baroreceptors (true or false):

The baroreceptor reflex does not affect cardiac output

Answer 14

False. The baroreceptor reflex does affect cardiac output.

Question 15

Regarding baroreceptors (true or false):

Peripheral chemoreceptors are excited by hypoxia and acidosis and elicit hypotension through peripheral vasodilatation

Answer 15

False. Peripheral chemoreceptors are excited by hypoxia and acidosis and elicit hypertension through vasoconstriction.

Question 16

Regarding the Valsalva manoeuvre (true or false):

Valsalva manoeuvre is forced inspiration against a closed glottis

Answer 16

False. The Valsalva manoeuvre is forced expiration against a closed glottis.

Question 17

Regarding the Valsalva manoeuvre (true or false):

In Phase I arterial blood pressure decreases as the thoracic aorta is compressed by the high intrathoracic pressure

Answer 17

False. In Phase I arterial blood pressure increases as the thoracic aorta is compressed by high intrathoracic pressure.

Question 18

Regarding the Valsalva manoeuvre (true or false):

In Phase IV there is a transient bradycardia

Answer 18

True

Question 19

Regarding the Valsalva manoeuvre (true or false):

In patients with autonomic neuropathy the blood pressure continues to fall in Phase II and does not overshoot in Phase IV

Answer 19

True

Question 20

Regarding the Valsalva manoeuvre (true or false):

On terminating the Valsalva manoeuvre, intrathoracic pressure falls to normal and the thoracic aorta is decompressed, so arterial blood pressure falls abruptly

Answer 20

True

Question 21

Regarding substances secreted by the endothelium (true or false):

Adenosine, bradykinin and histamine are vasodilators

Answer 21

True

Question 22

Regarding substances secreted by the endothelium (true or false):

Thromboxane A2 inhibits platelet aggregation

Answer 22

False. Thromboxane A2 encourages platelet aggregation.

Question 23

Regarding substances secreted by the endothelium (true or false):

Prostacyclin inhibits platelet aggregation and produces vasodilatation

Answer 23

True

Question 24

Regarding substances secreted by the endothelium (true or false):

Endothelins are the most potent naturally occurring vasoconstrictors in the body

Answer 24

True

Question 25

Regarding substances secreted by the endothelium (true or false):

Nitric oxide is synthesized by the endothelium from L-Arginine and is a potent vasodilator

Answer 25

True