CVS Part 1 & 2

Question 1

Overview of why we need a cardiovascular system (5 functions)

Answer 1

1. for transport of o2 and substrates (glucose, AA and FA) to cells.
2. to transport co2 and metabolites from cells for excretion.
3. distribution of hormones around the body (eg. adrenaline and insulin)
4. transport of defence mechanisms (eg. involving immune system)
5. thermoregulation

Question 2

Describe the conduction pathway of electrical activity through the heart

Answer 2

(1) Electrical activity generated in SA node (non-contractile tissue)
spreads out into atria to produce (2) contraction
(3) Electrical activity enters AV node (non-contractile tissue)
(4) Delays conduction before stimulating ventricles - allows ventricles to fill correctly -
(5) Excitation conducts rapidly through bundle of His into ventricles
(6) Excitation through purkinje fibres is conducted throughout the ventricles producing contraction and ejection

Question 3

What does “stroke volume” mean

Answer 3

volume of blood ejected from the heart per beat

Question 4

What does “heart rate” mean

Answer 4

number of heart beats per min

Question 5

What does “stroke volume” mean

Answer 5

volume of blood ejected from the heart per beat

Question 6

What does “cardiac output” mean

Answer 6

Volume of blood ejected from the heart per min (ml/min)

Question 7

What does “blood flow” mean

Answer 7

Volume of blood circulating per min

Question 8

What does “blood pressure” mean

Answer 8

Pressure of circulating BF on blood vessel walls

Question 9

What does “total peripheral resistance” mean

Answer 9

Resistance of blood vessels to blood flow

Question 10

How do you calculate “cardiac output”

Answer 10

heart rate x stroke volume

Question 11

What leads to heart failure?

Answer 11

A drop in stroke volume leads to poor cardiac output

Question 12

how do you calculate arterial blood pressure

Answer 12

cardiac output x total peripheral resistance

Question 13

What causes hypertension

Answer 13

high total peripheral resistance leads to high blood pressure - hypertension

Question 14

Blood helps regulate body temperature. What happens when it is cold?

Answer 14

the blood vessels lying close to the skin constrict to reduce blood flow, saving the heat within the body.

Question 15

What does pulmonary circulation involve?

Answer 15

oxygen-depleted blood from body tissues runs from the right atrium to the right ventricle of the heart into the right and left pulmonary arteries, which carry the blood into the right and left lungs.

Question 16

What does pulmonary circulation involve?

Answer 16

oxygen-depleted blood from body tissues runs from the right atrium to the right ventricle of the heart into the right and left pulmonary arteries, which carry the blood into the right and left lungs.
(Screenshot 2022-09-21 at 16.21.10)

Question 17

What does pulmonary circulation involve?

Answer 17

oxygen-depleted blood from body tissues runs from the right atrium to the right ventricle of the heart into the right and left pulmonary arteries, which carry the blood into the right and left lungs.
(Screenshot 2022-09-21 at 16.21.10)
Summary: The pulmonary circulation is between the heart and the lungs

Question 18

What does systemic circulation involve?

Answer 18

pumping oxygen-rich blood into the aorta. The aorta gives off smaller arteries that gradually branch into smaller vessels called arterioles.

Near the body tissues, these arterioles further divide into smaller vessels called capillaries. These capillaries form small networks called capillary beds, in which blood flow is reduced. This reduction in blood flow allows the exchange of gases, nutrients and waste products between the blood and tissues.

Then the capillaries regroup to form venules, which eventually drain into veins, and eventually into the two largest veins called the superior vena cava and the inferior vena cava, which collect blood from the entire body and empty into the right atrium. And once more, the pulmonary circulation cycle restarts.

Summary: the systemic circulation is between the heart and the rest of the body

Question 19

connections between two arteries are called

Answer 19

an arterioarterial anastomosis

Question 20

connections between two veins are called

Answer 20

a venovenous anastomosis.

Question 21

What is the hepatic portal venous system responsible for?

Answer 21

it directs the nutrient rich blood from the capillary beds of the digestive tract to the capillary beds of the liver.

Question 22

What are Anastomoses?

Answer 22

they are connections between blood vessels that serve as backup in case of an occlusion of an artery or vein.

Question 23

Where is the heart located?

Answer 23

It sits slightly shifted over to the left side in the mediastinum. It sits on top of the diaphragm.

Question 24

What is the serous pericardium?

Answer 24

It is a sac of fluid that the heart sits in

Question 25

What is the innermost layer of the heart called?

Answer 25

endocardium

Question 26

What is the endocardium made of?

Answer 26

a thin layer of endothelium

Question 27

Where does deoxygenated blood enter through?

Answer 27

through a blood vessel called the superior vena cava or through another vessel called the inferior vena cava in the right atrium

Question 28

name the veins of the heart?

Answer 28

superior and and inferior vena cava

Question 29

What is the coronary sinus?

Answer 29

this is a third opening of the right atrium which collects blood from coronary vessels returining from the myocardium

Question 30

What separates atria from the ventricles?

Answer 30

atrioventricular valves

Question 31

What is the name of the valve that allows blood into the right ventricle?

Answer 31

tricuspid valve

Question 32

what is pulmonary circulation?

Answer 32

deoxygenated blood leaving the right ventricle through the pulmonary artery to the lungs and oxygenated blood entering the left atrium via the pulmonary vein.

Question 33

what is pulmonary circulation?

Answer 33

deoxygenated blood leaving the right ventricle through the pulmonary artery to the lungs and oxygenated blood entering the left atrium via the pulmonary vein.

Question 34

what is the largest artery in the body?

Answer 34

aorta

Question 35

what is systemic circulation?

Answer 35

oxygenated blood leaving the left ventricle of the heart to be pumped around the body. Deoxygenated blood enters through the right atrium.

Question 36

Why is the left ventricle the strongest chamber of the heart?

Answer 36

Its because its part of the systemic circulation so it needs to pump blood around the body.

Question 37

What is systolic blood pressure?

Answer 37

This is the pressure in the arteries when the ventricles are squeezing out blood under high pressure.

Question 38

What is diastolic blood pressure?

Answer 38

This is when the ventricles are filling up more with blood, so its going to be slightly lower pressure.

Question 39

What is cardiac output?

Answer 39

This is the amount of blood that is pumped out by either ventricle over a period of time.

Question 40

What is venous return?

Answer 40

This is the rate at which the veins return blood back to the atria.

Question 41

Where is the sino-atrial node?

Answer 41

In the right atrium

Question 42

How do you decrease heart rate?

Answer 42

By inhibiting calcium channels using calcium channel blockers (CCBs) like verapamil and If channels using lvabradine

Question 43

Cardiac cycle:

Answer 43

1. ventricular filling followed by atria contraction
2. isovolumetric contraction
3. isovolumetric relaxation
4. ejection

Question 44

Cardiac cycle X@

Answer 44

1. Atrial contraction
2. Isovolumetric ventricular contraction
3. Rapid ventricular ejection
4. Reduced ventricular ejection
5. Isovolumetric ventricular relaxation
6. Rapid ventricular filling
7. Reduced ventricular filling

Question 45

What does Starling’s law state?

Answer 45

‘Increase in filling pressure and subsequent ventricular end-diastolic pressure produces an increase in contractile energy of cardiac myocytes’