Cardiac Physiology

Question 1

What is occurring during ventricular systole ? Which valves are open and closed?

Answer 1

Ventricles are beginning to contract after the atria are fully relaxed. The pressure in the ventricles builds forcing the pulmonary and aortic valves open .
The tricuspid and bicuspid valves are closed to prevent back flow.

Question 2

What in occurring during complete diastole?

Answer 2

During complete diastole the whole heart ( atria and ventricles) is relaxing and refilling with blood.

Question 3

Define cardiac output

Answer 3

The volume of blood pumped from the left ventricle into the aorta over a minute

Question 4

Define blood pressure

Answer 4

The force of blood against the atrial walls

It is essentially a measure of how hard the heart had to work to push blood around the body

Question 5

What is hemoglobin ?

Answer 5

Haemoglobin is found in red blood cells and helps carry oxygen around the body

Question 6

Name the 4 main vales in the heart

Answer 6

Tricuspid
Bicuspid/ Mitral
Aortic
Pulmonary

Question 7

Describe the valves system operating as blood flows through the heart

Answer 7

When pressure in the atrium is greater than that in the ventricles, the atrioventricular valves ( tricuspid and bicuspid) are forced open allowing blood to flow into the left and right ventricles. Here the pressure is higher in the ventricles than in the great veins and arteries forcing the semilunar valves ( aortic and pulmonary) open allowing blood to flow to the lungs and around the body .

Question 8

Describe what is occurring during atrial systole? Which valves are open and which are closed?

Answer 8

The atria are contracting whilst the ventricles are relaxed and ready to receive blood from the contracting atria.
The pulmonary valve and the aortic valves are closed during atrial systole

Question 9

Give a detailed description of the pulmonary circuit

Answer 9

Superior/inferior vena cava –> Tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary artery –> lungs

Question 10

Give a detailed explanation of systemic circulation

Answer 10

Pulmonary vein –> left atrium –> bicuspid valve –> left ventricle –> aortic valve –> body

Question 11

What is the role of coronary arteries ?

Answer 11

There are two coronary arteries , left and right, which supple the myocardium with oxygen rich blood.

Question 12

What is the role of cardiac veins ?

Answer 12

Return deoxygenated blood from myocardium back to the heart to be oxygenated in pulmonary circuit.