CVS physiology 4

Question 1

Where are baroreceptors located?

Answer 1

Carotid sinus and aortic arch

Question 2

Where does information from baroreceptors travel to?

Answer 2

Medullary cardiovascular centres

Question 3

What nerves carry information from baroreceptors in carotid sinus to the brain?

Answer 3

Glossopharyngeal nerve

Question 4

What is the valsalva manoeuvre?

Answer 4

Forced expiration against a closed glottis

Question 5

What are the 5 stages of the valsalva manoeuvre?

Answer 5

• Increased thoracic pressure is transmitted through to aorta
• Increased thoracic pressure reduces the filling from veins
• Reduced MAP is detected by baroreceptors
• At the end of the manoeuvre, decreased in thoracic pressure is transmitted through to aorta
• Venous return is restored which increases SV

Question 6

What effect does an increase in thoracic pressure have on mean arterial pressure, and why?

Answer 6

Increase in thoracic pressure causes decreased venous return, which decreases mean arterial pressure.

Question 7

How is blood pressure regulated long term?

Answer 7

Controlling plasma volume via the kidneys

Question 8

What 3 hormone systems are used to control plasma volume?

Answer 8

• Renin-angiotensin-aldosterone system
• Antidiuretic factor (ADH, vasopressin)
• Atrial natriuretic peptide and brain natriuretic peptide

Question 9

Where is renin produced?

Answer 9

Juxtaglomerular cells of the kidney

Question 10

What triggers renin production?

Answer 10

Activation of sympathetic nerves to the juxtaglomerular apparatus

Question 11

What is the role of renin?

Answer 11

Converts angiotensinogen to angiotensin I, which then is converted by angiotensin converting enzyme to form angiotensin II

Question 12

What is the role of angiotensin II?

Answer 12

• Stimulates release of aldosterone from the adrenal complex
• Increases release of ADH from pituitary
• Causes vasoconstriction

Question 13

Where is antidiuretic hormone produced?

Answer 13

Synthesised in the hypothalamus and released for the posterior pituitary gland

Question 14

Which triggers the release of antidiuretic hormone?

Answer 14

• Decrease in blood volume
• Increase in osmolarity of interstitial fluid
• Circulating angiotensin II

Question 15

What is the role of antidiuretic hormone?

Answer 15

Increases the permeability of the collecting duct to water, therefore reduces diuresis and increases plasma volume.

Also causes vasoconstriction

Question 16

What impact does antidiuretic hormone have on mean arterial pressure?

Answer 16

Causes increased MAP

Question 17

Where is atrial natriuretic peptide (ANP) produced?

Answer 17

Myocardial cells in the atria

Question 18

What is brain natriuretic peptide (BNP) produced?

Answer 18

Myocardial cells in the ventricle

Question 19

What triggers the release of ANP and BNP?

Answer 19

Increased distension of atria and ventricles

Question 20

What is the role of ANP and BNP?

Answer 20

• Increased Na+ excretion (natriuresis)
• Inhibits release of renin
• Acts on medullary CV centres to reduce MAP

Question 21

What effect do ANP and BNP have on mean arterial pressure?

Answer 21

Causes decrease MAP