Mass transport (HEART + CIRCULATION)

Question 1

Define double circulatory system and what does it provide

Answer 1

Blood flows twice through the heart for each circulation of the bod–> this means:
Blood pressure increases, therefore rate of blood flow to the tissues is great
Delivery of oxygen to the cells is quicker, this is important in mammals as they have a high metabolism.

Question 2

What is meant by an closed circulatory system is humans

Answer 2

Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness.

Question 3

Which side of the heart pumps oxygenated blood

Answer 3

Left (actually right on paper) pumps oxygenated blood
Right (actually left on paper) carried deoxygenated blood

Question 4

Why is the right ventricle thinner than the left ventricle

Answer 4

Right ventricle only has to pump blood to the lungs whereas left ventricle pumps blood around the body

Question 5

Give the list of all of the blood vessels in the heart starting with aorta

Answer 5

Aorta
Pulmonary vein
Semi lunar valve
Left atrium
Bicuspid valve
Left ventricle
Right ventricle
Tricuspid valve
Right atrium
Vena Cava
Pulmonary artery

Question 6

Give the equation for cardiac output

Answer 6

Stroke volume x heart rate

Question 7

Give the three stages of the cardiac cycle

Answer 7

Atrial systole
Ventricular systole
Diastole

Question 8

Describe atrial systole

Answer 8

Atriums contract
Volume of atriums decrease so pressure increases
This pushes blood from atriums into ventricles so atrioventricular valves are open

Question 9

Describe ventricular systole

Answer 9

(atriums are now relaxed) Ventricles contract from the apex of the heart
Volume of ventricles decreases so pressure increases so AV valves close
Semi lunar valves open as pressure is greater in ventricles than aortas so blood is forced into the aortas

Question 10

Describe diastole

Answer 10

Both atrium and ventricles relax
Blood is brought by vena cava and pulmonary vein which increases the volume of atriums as blood flows into them, increasing pressure which forces AV valves open
Some blood flows passively down into ventricles

Question 11

When do the valves open and close in the cardiac cycle

Answer 11

Open - when pressure behind them is greater:
AV valves open when pressure in atriums is greater than pressure in ventricles
Semi lunar valves open when pressure in ventricles is greater than pressure in aortas

Close - when pressure in front them is greater:
AV valves close when pressure in ventricles is greater than pressure in atriums
Semi lunar valves close when pressure in atriums is greater than pressure in aortas

Question 12

When drawing a graph of the cardiac cycle, which comes first, the AV valves opening or closing?

Answer 12

AV valves closing comes first