Lecture 28. Pulmonary Circulation and Autonomic Control of the Cardiovascular System

Question 1

What innervates the heart?

Answer 1

Both arms of the automatic nervous system (parasympathetic and sympathetic)

Question 2

What innervates blood vessels?

Answer 2

Only the sympathetic

Question 3

What innervate pacemakers and atrial muscle?

Answer 3

Parasympathetic/sympathetic nerves

Question 4

How are chronotropic effects exerted?

Answer 4

By altering the pacemaker potential

Question 5

What does the sympathetic arm drive the heart through?

Answer 5

Noradrenaline
Increased rate: a positive chronotropic effect
Increased conduction: a positive dromotropic effect

Question 6

What does the parasympathetic arm slow the heart through?

Answer 6

Acetylcholine
Decreased rate: a negative chronotropic effect
Decreased conduction: a negative dromotropic effect

Question 7

What nervous system alters contractility of the heart?

Answer 7

Sympathetic increases contractility through NA enhancing Ca²⁺ release in myocytes
A positive inotropic effect

Question 8

What do sympathetic nerves cause?

Answer 8

Vasoconstriction

Question 9

What do sympathetic nerves release onto smooth muscle?

Answer 9

Noradrenaline

Question 10

How does vasoconstriction occur?

Answer 10

Increasing noradrenaline release
1) Control resistance of systemic circulation
2) Regulate flow to organs or tissues

Question 11

How does vasodilation occur?

Answer 11

Decreasing noradrenaline release
1) Control resistance of systemic circulation
2) Regulate flow to organs or tissues

Question 12

What is the formula for calculating mean arterial blood pressure (MAP)?

Answer 12

Mean arterial blood pressure (MAP) = CO x TPR

Question 13

What do peripheral nerves from carotid body do?

Answer 13

Sense blood pressure and alter autonomic drive

Question 14

What does the baroreceptor reflex alter?

Answer 14

Cardiac output and peripheral

Question 15

What is secreted by the kidney that is an important factor in regulating blood volume?

Answer 15

Renin

Question 16

What are the two things Angiotensin II does that affect the circulation

Answer 16

Rapid: Powerful vasoconstricter - increase peripheral resistance and venous tone
Slow: Secretion of aldosterone increases retention of Na⁺, thirst, ECF and plasma volume and filling pressure

Question 17

What do atrial stretch receptors do?

Answer 17

Help regulate extracellular fluid volume

Question 18

What do atria secrete?

Answer 18

Secrete atrial natriuretic peptide/factor (ANP)

Question 19

What does the release of ANP cause?

Answer 19

Renal excretion of Na⁺, and reduction of ECF volume

Question 20

What can adjust blood flow to a particular tissue?

Answer 20

Adjusting vasomotor tone

Question 21

What counters increased vasomotor tone?

Answer 21

Potassium and Adenosine

Question 22

What governs vessel dilation in the pulmonary circulation?

Answer 22

Oxygen levels and adenosine
Low oxygen levels result in vasoconstriction

Question 23

What does hypoxia induce?

Answer 23

Adenosine release causes vasoconstriction in the pulmonary circulation