Lecture 8: The Heart as a Pump

Question 1

What circuit move blood to and from the lungs?

Answer 1

The Pulmonary circuit

Question 2

What circuit moves blood to and from the tissues of the body?

Answer 2

The Systemic circuit

Question 3

How many chambers of the heart are there?

Answer 3

Four

Question 4

How many directions does blood flow in?

Answer 4

One

Question 5

What direction does arterial blood flow in?

Answer 5

Away from the heart

Question 6

What direction does Venous fluid flow in?

Answer 6

Towards the heart

Question 7

How many pumps are in the heart and how can their location be described?

Answer 7

There are 2 pumps and they are in series

Question 8

When pumping blood which pumps work together in synchronisation?

Answer 8

The left/right

Question 9

When contracting what contracts first?

Answer 9

Atria

Question 10

When the heart contracts what contracts second?

Answer 10

Ventricles

Question 11

What controls the flow of blood between the Atria and ventricles?

Answer 11

Tricuspid and bicuspid (mitral) valves

atrioventricular valves

Question 12

What controls the flow of blood from the ventricles out to the circulatory vessels?

Answer 12

Aortic and pulmonary valves

Semilunar valves

Question 13

What are Thin filaments made of?

Answer 13

Actin

Question 14

What are Thick filaments made of?

Answer 14

Myosin

Question 15

What causes mysoin-actin cross bridges to form in cardiac muscle?

Answer 15

Calcium levels increasing

Question 16

Where are calcium ions released from into the cardiac muscle?

Answer 16

Sarcoplasmic reticulum

Question 17

How do myosin-actin interactions generate force?

Answer 17

Myosin pulls on actin to shorten the sarcomere

Question 18

What myocytes are activated during each heart beat?

Answer 18

All the Myocytes

Question 19

How can force be increased during the contractions of the heart?

Answer 19

Increasing the extent of of cross bridge formations

Question 20

How can the extent of cross bridge formations be increased?

3

Answer 20

• increase cytosolic calcium level
• increase number of cross-bridges formed
• increase force of contraction

Question 21

What causes cardiac relaxation?

Answer 21

Decrease in cytosolic calcium levels by pumping calcium back into the sarcoplasmic reticulum

Question 22

What happens to the heart during Diastole?

2

Answer 22

• Relaxes

- Falling pressure

Question 23

What happens to the heart during Systole?

2

Answer 23

• Contraction

- Rising pressure

Question 24

What happens during Atrial systole?

Answer 24

• Atria contract moving blood to the ventricles
• AV valves open
• Semilunar valves are closed

Question 25

What happens in the Isovolumetric ventricular contraction? | 5

Answer 25

- Atria relax - Ventricles contract - AV valves close - Semilunar valves close - Pressure increases

Question 26

What happens in the Ventricular ejection phase?

Answer 26

- Blood is pushed out of the ventricles - ventricles contract - Semilunar valves open

Question 27

What happens during Isovolumetric ventricular relaxation phase

Answer 27

- Semilunar valves close - AV valves close - Pressure decreases

Question 28

What has a higher pressure systemic or pulmonary circuit?

Answer 28

Systemic

Question 29

What is diastolic blood pressure?

Answer 29

Your lowest blood pressure

Question 30

What is systolic blood pressure?

Answer 30

Your highest blood pressure

Question 31

What is the pulse pressure?

Answer 31

The difference between the diastolic and systolic pressure

Question 32

What is mean pressure?

Answer 32

The average pressure over a cardiac cycle

Question 33

Why is the mean pressure lower than half way?

Answer 33

Because we spend more time at diastolic pressure

Question 34

What is hypertension?

Answer 34

A high blood pressure

Question 35

What is hypotension?

Answer 35

A low blood pressure

Question 36

What is the equation for flow?

Answer 36

Flow = Pressure difference / Resistance

Question 37

Which circuit has a higher resistance?

Answer 37

Systemic circuit