Lecture 10: Controlling the Heart and Blood Pressure

Question 1

What generates pressure for systemic circulation?

Answer 1

The left ventricle

Question 2

What is linked to the high pressure in the large systemic arteries?

Answer 2

Ventricular contraction and ejection of blood

Question 3

What is pulsatility in major arteries due to?

Answer 3

Non-continuous pumping of blood (systole/diastole)

Question 4

What is Mean Arteriole blood Pressure a critically important determinant of?

Answer 4

Blood flow

Question 5

Is blood pressure high or low in major arteries?

Answer 5

High

Question 6

Where does blood pressure fall steeply?

Answer 6

Across the Arterioles, Capillaries and Venules

Question 7

What is reduced due to the steep fall of blood pressure across Arterioles, Capillaries and Venules?

Answer 7

The oscillatory nature of blood pressure

Question 8

Is blood pressure high or low in veins?

Answer 8

Low

Question 9

What does the large pressure difference between the arterial and venous sides of the circulatory system do?

Answer 9

Creates a driving force for blood flow

Question 10

What does ejection of blood into the arterial system maintain?

Answer 10

Arteriole blood volume and blood pressure

Question 11

What is arteriole blood volume and pressure determined by?

Answer 11

Balance between blood flow “in” and “out”

Question 12

What are effects of blood flow into the arteries?

3

Answer 12

• Fills arteries
• Increases arterial blood volume
• Raises arteriole pressure

Question 13

What are effects of blood flow out of the arteries?

3

Answer 13

• Drains arteries
• Decreases arterial blood volume
• Lowers arterial pressure

Question 14

What are causes of blood flow in to the arteries?

3

Answer 14

• Ventricular contraction
• Ejection of blood
• Cardiac output

Question 15

What are contributing factors to blood flow out of the arteries?
(2)

Answer 15

• Capillary flow

- Controlled by resistance of the arteries

Question 16

A balance of blood flow in and blood flow out determines what?

Answer 16

Blood pressure

Question 17

What does an increase of cardiac output do to blood flow?

Answer 17

Increases inflow

Question 18

What does an increase in resistance do to blood flow?

Answer 18

Decreases outflow

Question 19

What does an increase in cardiac output and resistance do?

Answer 19

Increases arterial volume and pressure

Question 20

What is the equation for Mean arteriole pressure?

Answer 20

Arterial pressure = Cardiac output x Total peripheral resistance

Question 21

What is cardiac output determined by?

Answer 21

Stroke volume and heart rate

Question 22

What is stroke volume determined by?

Answer 22

Contraction strength

Question 23

What is heart rate determined by?

Answer 23

Contraction speed

Question 24

What is the approach of small animals to meeting cardiac output needs?

Answer 24

High heart rates with a small stroke volume

Question 25

What is the approach of large animals to meeting cardiac output needs?

Answer 25

High stroke volume with a small heart rate

Question 26

How does a failing heart meet the needs of cardiac output?

Answer 26

Increased heart rate to make up for a small stroke volume

Question 27

What happens to the heart during exercise?

Answer 27

Heart rate/stroke volume increase leading to a larger cardiac output

Question 28

What 2 systems are used by the brain to control and respond to changes in blood pressure?

Answer 28

- Afferent input | - Effect output

Question 29

What are baroreceptors?

Answer 29

Blood pressure sensors

Question 30

What kind of receptors are baroreceptors?

Answer 30

Stretch receptors

Question 31

Where are baroreceptors located?

Answer 31

In the walls of arteries

Question 32

How does the brain sense pressure changes in the arteries?

Answer 32

Through baroreceptors

Question 33

What does the carotid artery supply blood too?

Answer 33

The brain

Question 34

What do baroreceptors do when the blood pressure is optimal in arteries?

Answer 34

It send a signal to the brain at a constant optimal pace

Question 35

What do baroreceptors do when the blood pressure rises in arteries?

Answer 35

It sends a signal to the brain at an increased pace above what is seen as optimal

Question 36

What do baroreceptors do when the blood pressure falls in arteries?

Answer 36

It sends a signal to the brain at an decreased pace below what is seen as optimal

Question 37

What 2 signalling systems does the brain use to control heart rate?

Answer 37

Parasympathetic/sympathetic systems

Question 38

What system used by the brain slows down heart rate?

Answer 38

The parasympathetic system

Question 39

What system used by the brain speed up heart rate?

Answer 39

The sympathetic system

Question 40

What pathway does the parasympathetic system follow to innervate the sinoatrial and atrioventricular nodes?

Answer 40

The vagus nerve

Question 41

What pathway does the sympathetic system follow to innervate the sinoatrial, atrioventricular nodes and the ventricle walls?

Answer 41

Down to the sympathetic trunk ganglion then out through the sympathetic cardiac nerves

Question 42

What parts of the heart are innervated by the parasympathetic nervous system?

Answer 42

SA and AV nodes

Question 43

What parts of the heart are innervated by the sympathetic nervous system?

Answer 43

SA/AV nodes and the ventricle walls

Question 44

How does the parasympathetic nervous system act on the SA/AV nodes?

Answer 44

It slows the amount of the signals sent by the sinoatrial node and increases the length of the delay on signals induced by the AV node

Question 45

How does the sympathetic nervous system act on the SA/AV nodes?

Answer 45

It increases the amount of the signals sent by the sinoatrial node and decreases the length of the delay on signals induced by the AV node

Question 46

What happens to stroke volume as the body is positioned upright during the tilt test?

Answer 46

It decreases slightly

Question 47

What happens to cardiac output as the body is positioned upright during the tilt test?

Answer 47

It decreases

Question 48

What happens to heart rate as the body is positioned upright during the tilt test?

Answer 48

It increases

Question 49

How is MAP maintained whilst cardiac output decreases during the tilt test?

Answer 49

Total peripheral resistance increases

Question 50

What is Cardiac output calculated by?

Answer 50

Cardiac output = stroke volume x heart rate