The Heart

Question 1

where and what type of blood does the right side of the heart pump

where and what type of blood does the left side of the heart pump

Answer 1

• Right side of the heart pumps DEoxygenated blood to the lungs
• The left side of the heart pumps OXygenated blood, to the rest of the body

Question 2

How do valves in the heart prevent blood from flowing the wrong way

Answer 2

• If there is high pressure behind a valve, it is FORCED OPEN
• If there is high pressure INFRONT of a valve, then it is forced shut
• valves help prevent blood from flowing in the wrong direction.

Question 3

why is the left ventricle wall thicker than the right ventricle wall

Answer 3

• this is because the left ventricle ( the left side of the heart, has to push blood ALL THE WAY ROUND THE BODY.
• ventricles have thicker walls than atria, because they have to push blood out of the heart

Question 4

What is the Cardiac cycle

Answer 4

The cardiac cycle is the atria and ventricles constantly contracting and relaxing, which keeps the blood continuously circulating round the body

• The volumes of the atria and ventricles change as they alter the pressure in each chamber

Question 5

Cardiac cycle process ( 3 Stages)

1) Atria contract, ventricles relax

Answer 5

atria contract, ventricles relax, which decreases their volume and increases their pressure
- THis pushes blood into the ventricles through the AV valve .

• There is a slight increase in ventricular pressure and volume as the ventricles receive the ejected blood from the contracting atria.

Question 6

Cardiac cycle process ( 3 stages)

2) Ventricles contract, atria relax

Answer 6

• Atria relax, ventricles contract increasing their pressure
• Pressure becomes higher in the ventricles than in the atria, forcing the AV valve shut to prevent back flow
• The high pressure in the ventricles, causes the semi lunar valve to open, causing blood to be forced out of the pulmonary artery and the aorta

Question 7

Cardiac cycle process

3) Ventricles relax AND atria relax too

Answer 7

• BOTH ventricles and atria relax
• High pressure in the pulmonary artery and the aorta, causes the semi lunar valve to shut to prevent back flow.
• Atria fill with blood due to high pressure in the vena cava and the pulmonary vein
• ventricular pressure is less than atrial pressure.
  causes the AV valve to open and blood flows passively into the ventricles
• atria contract and the entire cycle starts again

Question 8

what is cardiac output and how do you calculate it

Answer 8

cardiac output is the volume of blood pumped by the heart per minute ( cm ^3 min ^-1)

USE THIS FORMULA
Cardiac output= heart rate x stroke volume

heart rate is the number of beats per minute
and stroke volume is the volume of blood pumped during each heart beat