Topic 9 - Intro to Cardiovascular system

Question 1

When does the heart begin to start beating and pump blood?

Answer 1

Around day 21-22/ 3 wks after fertilisation

Question 2

What are the roles of the cardiovascular system?

Answer 2

• provide nutrients e.g oxygen
• remove waste products e.g urea (product of protein degradation

Question 3

What is the resting heart rate?

Answer 3

40-90 beats per min

Question 4

What can be a max rate of the heart for a marathon runner?

Answer 4

~225bpm

Question 5

How long does it take for you to die after your heart stops?

Answer 5

5 minutes

Question 6

What are the parts of a pump and how many pumps does the heart have?

Answer 6

• The heart has 2 pumps: left and right

PUMPS:
- Atria = small chambers receiving blood from large veins & contract to squeeze blood into ventricles
- Ventricles = big chambers receiving blood from atria & contract to eject blood to arteries

Question 7

What are the roles of the right/left atriums/ventricles?

Answer 7

RIGHT:
They pump blood into pulmonary circulation to lungs, receiving O2

LEFT:
They pump blood into systemic circulation to rest of body, supplying O2 & nutrients

Question 8

Where is the heart located?

Answer 8

In the pericardium (fluid-filled sac)

Question 9

What does the heart consist of?

Answer 9

• Epicardium (outer lining = connective tissue & fat)
• Myocardium (cardiac muscle)
• Endocardium (inner lining = endothelial cells)

Question 10

What are the cell types in the heart?

Answer 10

• Cardiomyocytes = atria & ventricles & typical contracting heart muscle cells responsible for blood movement
• Fibroblasts = make collagen for structural support
• Fast conduction fibres = spread action potentials throughout heart
• Pacemaker cells = act as spark plug, generating action potential -> contraction. Located in sinoatrial node & atrioventricular node

*NOTE: Pacemaker cells don’t contract, they cause the action potential though.

Question 11

What are the valves in the heart?

Answer 11

• Atrioventricular valves = allow blood move from atria to ventricle
  NOTE: Right = tricuspid valve, Left = mitral/bicuspid valve
• Semilunar valves = allow blood move from ventricle to artery
  NOTE: Right = aortic valve, Left = pulmonary valve

*EXTRA NOTE: Valves open/close depends on pressure

Question 12

What is the flow of blood after it leaves the heart?

Answer 12

Ventricle -> artery -> arteriole -> capillary -> venule -> vein -> vena cava (big vein) -> atrium

*Note what they are:
- Arteries = carry blood under high pressure
- Arterioles = determine blood flow to organ by change diameter (resistance)
- Capillaries = site exchange b/w blood & tissue
- Venules & veins = low pressure, high capacity vessels.