THE MAMMALIAN HEART;CARDIAC CYCLE;

Question 1

The 1st step of the movement of blood in the heart

Answer 1

Blood enters the atria it cannot yet pass into the ventricles because the bicuspid (LA) and the tricuspid valve (RA) are closed

Question 2

The 2nd step of the movement of blood in the heart

Answer 2

The walls of the atria contract, raising the blood pressure of the blood, which forces the bicuspid(LA) and tricuspid (RA) valves open, blood passes through to the ventricles

Question 3

The 3rd step of the movement of blood in the heart

Answer 3

When the ventricles are full, they contract, increasing the pressure of the blood in the ventricles, which CLOSES the bicuspid (LA) and tricuspid valves again. Blood CANNOT return to the atria

Question 4

The 4TH step of the movement of blood in the heart

Answer 4

The ventricles continue to contract and the pressure continues to increase, forcing the semi lunar valves (at the base of the aorta and pulmonary artery) open Blood is ejected into the 2 arteries.

Question 5

What does the pulmonary artery do?

Answer 5

Takes deoxygenated blood to the lungs

Question 6

What does the aorta do?

Answer 6

Takes oxygenated blood to all parts of the body

Question 7

The 4TH step of the movement of blood in the heart

Answer 7

As the ventricles empty, higher pressure in the pulmonary artery and aorta closes the semi lunar valves

Question 8

The 5TH step of the movement of blood in the heart

Answer 8

The cycle then begins again as the atria start to fill with oxygenated blood

Question 9

What are the bicuspid and tricuspid valves sometimes referred to as?

Answer 9

Atrioventricular valves

Question 10

Why are the bicuspid and tricuspid valves sometimes referred to in another way?

Answer 10

They both control the passage of blood from an atrium to a ventricle