The events of the cardiac cycle

Question 1

How does blood enter the right atrium

Answer 1

Superior and inferior vena cava

Question 2

Why does blood flow straight through from the vena cava to the right atrium

Answer 2

Nothing separating them ie no valves

Question 3

What valve separates the right atrium and right ventricle

Answer 3

Tricuspid valves (AV valves)

Question 4

What valve separates the right ventricle from the lungs

Answer 4

Pulmonary valve

Question 5

What valve separates the left atrium from the left ventricle

Answer 5

AV valves (bicuspid/mitral)

Question 6

What valve separates the left ventricle from the aorta

Answer 6

Aortic valve

Question 7

What is the significance of the volume of blood pumped from the RHS and LHS of heart

-What is the exact volume

Answer 7

Same

-5 Litres/ minute

or

70ml/beat

Question 8

What is the pressure generated from LHS like compared to the RHS and why

Answer 8

Pressure generated is 4x greater in LHS because the LHS needs to overcome the pre-existing pressure in the system

Question 9

What are systole and diastole

Answer 9

Systole- contraction

Diastole-relaxation of ventricle

Question 10

What are the relative pressures like in atrial systole

Answer 10

Rise in atrial pressure and same relative rise in ventricular pressure however atrial pressure is just a bit above.

Aortic pressure falls because blood is not being flowed into it

Question 11

Relative pressures as the wave of excitation goes to the ventricles

Answer 11

Aortic pressure still falls because blood still not flowing to it

Question 12

Relative pressures and what happens during isovolumetric ventricular contraction

Answer 12

• Increase in ventricular pressure closes AV valves

- VEntricular pressure is less than aortic pressure so the aortic valve is still closed

Question 13

Relative pressures and actions in ventricular ejection

Answer 13

-Ventricular pressure exceeds aortic pressure and therefore the aprtic valve opens and blood is ejected

Question 14

What happens in isovolumetric ventricular relaxation

Answer 14

• VEntricular pressure less than aortic pressure so aortic valves close
• Ventricular pressure is still greater than atrial pressure therefore the AV valves are still shut
• Pressure falls but there is no filling

Question 15

What happens in ventricular filling

Answer 15

Ventricular pressure is less than atrial pressure so AV valves open and blood enters the ventricles

Question 16

What is Ejection Fraction

Answer 16

The volume of blood emptied by the heart (because heart does not empty all of its content as it would require a lot of energy to refill the whole heart from scratch)

Question 17

What do pulsations in the internal jugular vein reflect

Answer 17

Right atrial pressure changes as there is no valve separating the vena cava and the right atrium

Question 18

What are the two sounds you can hear with a stethoscope

Answer 18

First- Closure of the AV valves as the left ventricular pressure exceeds atrial pressure

Second- Closure of the aortic valve/pulmonary valve

Question 19

What is a raised jugular venous pulse an indication of

Answer 19

Right hand side heart failure because the right hand side can’t pump effectively which is reflected in the venous side

Question 20

When does the aortic valve open

Answer 20

During systole

Question 21

When does the aortic valve close

Answer 21

Start of diastole

Question 22

When does the mitral valve open

Answer 22

During diastole

Question 23

When does the mitral valve close

Answer 23

Start of systole