Cardiovascular System

Question 1

What is coronary circulation?

Answer 1

Supply of oxygen rich blood to the heart tissue

Question 2

Which arteries supply the heart with blood?

Answer 2

• right coronary artery

- left coronary artery

Question 3

Where do the coronary arteries branch from?

Answer 3

Aorta

Question 4

What is the heart?

Answer 4

Muscular pump that keeps blood flowing through the vessels

Question 5

What do vessels do?

Answer 5

Deliver blood to the body and then return it back to the heart

Question 6

What is the pulmonary circuit?

Answer 6

• right side of the heart

- carries O2 poor blood to the lungs for gas exchange and then returns it to the heart

Question 7

What is the systemic circuit?

Answer 7

• left side of the heart

- carries O2 rich blood to the body and returns O2 poor blood back to the heart

Question 8

What is coronary circulation?

Answer 8

Hearts blood supply - O2

Question 9

What are the three layers of the heart wall?

Answer 9

• endocardium
• myocardium
• epicardium

Question 10

Endocardium

Answer 10

• innermost lining
• simple squamous epithelium overlying a thin layer of loose Ct
• continuous with the inner lining of blood vessels

Question 11

Myocardium

Answer 11

• cardiac muscle

- thickest layer

Question 12

Epicardium

Answer 12

• simple squamous epithelium overlying a thin layer of loose CT

Question 13

What is systole?

Answer 13

Contraction

Question 14

What is diastole?

Answer 14

Relaxation

Question 15

What are the major branches off the aorta?

Answer 15

• brachioceohalic artery: right subclavian artery and right common carotid artery
• left common carotid artery
• left subclavian artery

Question 16

Embryological development of the heart

Answer 16

• derived from mesoderm

- Heart bulge forms the heart: original near head but undergoes lateral folding to end up in correct position

Question 17

When does the heart start beating?

Answer 17

Beginning of week 4

Question 18

What are the three layers of blood vessels?

Answer 18

• tunica intima
• tunica media
• tunica adventitia

Question 19

Characteristics of the tunica intima

Answer 19

• endothelium
• basement membrane
• loose CT

Question 20

Characteristics of the tunica media

Answer 20

• smooth muscle
• collagen
• elastin (sometimes)

Question 21

Characteristics of the tunica adventitia

Answer 21

• loose CT

- often interweaves itself with tissue of neighbouring structures/organs

Question 22

What are the 4 valves of the heart?

Answer 22

• right atrioventricular valve (3 cusps)
• left atrioventricular valve (2 cusps)
• pulmonary valve (3 cusps)
• aortic valve (3 cusps)

Question 23

What are the different circuits of the heart?

Answer 23

• pulmonary

- systemic

Question 24

The walls of which ventricle is thicker?

Answer 24

Left

Question 25

Action potential of the heart

Answer 25

- resting membrane potential of -90mV - Na+ floods in - depolarisation - Ca2+ prolongs depolarisation - K+ channels open at end of plateau

Question 26

Conduction in the heart

Answer 26

Sinoatrial node - atrioventricular node - atrioventricular bribers - branching fibres - purkinje fibres

Question 27

What is systole?

Answer 27

Contraction

Question 28

What is diastole?

Answer 28

Relaxation

Question 29

What are the phases of the cardiac cycle?

Answer 29

1. Ventricular filling 2. Ventricular filling 3. Isovolumetric contraction 4. Ventricular ejection 5. Isovolumetric relaxation 6. Ventricular filling

Question 30

What is the cardiac output formula?

Answer 30

CO= SV x HR

Question 31

What is the average stroke volume at rest?

Answer 31

70mL

Question 32

How is heart rate changed?

Answer 32

Change heart rate | Change stroke volume

Question 33

1. Ventricular filling (2/3)

Answer 33

- all chambers relaxed - AV valves are open - blood flows from atria to ventricles

Question 34

2. Ventricular filling (1/3)

Answer 34

- atrial systole - completes the process of ventricular filling - each ventricle contains and end diastolic volume

Question 35

3. Isovolumetric contraction

Answer 35

- ventricular contraction begins - AV valves close as some blood is forced back - pressure in ventricles increases but not enough to open semilunar valves

Question 36

4. Ventricular ejection

Answer 36

- ventricular systole continues - when pressure of yeh ventricles exceeds the arteries the semilunar valves open - ventricles eject blood

Question 37

5. Isovolumetric relaxation

Answer 37

- ventricular systole ends - ventricular pressure drops - semilunar valves close (AV valves are still closed)

Question 38

6. Ventricular filling

Answer 38

- all chambers relaxed again - ventricular pressure drops below atrial pressure - AV valves open - blood accumulated in atria rushes into ventricles

Question 39

Why does standing for a long time make someone faint?

Answer 39

- standing means that the muscles around the deep veins in the leg are not contracting - therefore blood is not being forced back towards the heart and venous return is compromised - this reduces cardiac output and results in insufficient blood supply reaching the brain, and hence fainting occurs