Cardiovascular system; Lecture 6 - the cardiac cycle

Question 1

Label this diagram of the heart

Answer 1

Question 2

What is diastole?

Answer 2

Fillng of the heart

Question 3

What is systole?

Answer 3

Contraction of myocardium and ejection of blood

Question 4

How long does one cardiac cycle last?

Answer 4

0.8 seconds

Question 5

What vein drains into the superior vena cava?

Answer 5

Azygous vein drains the posterior intercostal veins and empties into the superior vena cava

Question 6

What is the function of valves?

Answer 6

Valves keep blood moving in the right direction and prevents it flowing backwards

Question 7

Explain the 8 steps of blood flow through the right side of the heart

Answer 7

1. Deoxygenated blood travels from the superior and inferior vena cava into the right atrium
2. Tricuspid valve opens
3. Deoxygenated blood flows into right ventricle
4. Pulmonary valve opens
5. Deoxygenated blood leaves the right ventricle
6. Deoxygenated blood enters the pulmonary trunk
7. Deoxygenated blood travels from the pulmonary artery into the right and left pulmonary arteries
8. Deoxygenated blood travels from the right and left pulmonary arteries to the right and left lung respectively

Question 8

Explain the 5 steps of blood flow through the left side of the heart

Answer 8

1. Oxygenated blood flows from the pulmonary veins into the left atria
2. Mitrial/ bicuspid valve opens
3. Oxygenated blood flows into right ventricle
4. Aortic semi lunar valve opens
5. Oxygenated blood flows from left ventricle into the aorta

Question 9

Draw a diagram of the left ventricular valves

Answer 9

Mitral valve

Question 10

What do papillary muscles do?

Answer 10

They are attactched to the veins of the mitral valve

They pull the valves inwards towards the ventricles to prevent them bulging towards the atria whent the ventricles contract

Question 11

What are the 4 phases of diastole?

Answer 11

1. Isovolumetric ventricular relaxation
2. Rapid ventricular filling
3. Slow ventricular filling
4. Atrial contraction

Question 12

What are the 2 stages of systole?

Answer 12

1. Isovolumetric ventricular contraction
2. Ejection

Question 13

Where can the heartbeat be found?

Answer 13

In all areas of auscultation

Question 14

What causes the first heart sound? (lub)

Answer 14

closing of the atrialventrcular valves - closure of the mitrial / tricuspid valve

Question 15

what causes the second sound? (dub)

Answer 15

closing of the semi lunar valves (aortic and pulonary valves)

Question 16

What is the difference between systole and diastole?

Answer 16

Systole is contraction

Diastole is relaxation

Question 17

Give the 5 mechanical events of the cardiac cycle (in detail)

Answer 17

Question 18

Explain the changes in volume and pressure of the heart durng the different stages of the cardiac cycle (Wiggers diagram)

Answer 18

Question 19

Explain the electricular activity during the cardiac cycle

Answer 19

Question 20

What is stroke volume?

Answer 20

Volume of blood ejection from the left ventricle with each cardiac cycle

Question 21

What is cardiac output?

Answer 21

Volume of blood ejected from the left ventricle each minute

Question 22

How do we calculate cardiac output?

Answer 22

Cardic output = heart rate (HR) x stroke volume (SV)