Mammalian heart

Question 2

The structure

Question 4

The structure of heart: tendons

Answer 4

They keep the tricuspid & bicupid valves from flipping over into the atria during ventricular systole

Question 5

function: Right atrium

Answer 5

Recieves deoxygenated from the organs of the body except lungs via the venacava and pumps it into the right ventricle

Question 6

function: left atrium

Answer 6

Recieves oygenated blood from lungs via pulmonary vein

Question 7

function: tricuspid & biscupid valves (atrioventricular)

Answer 7

Prevents backflow of blood into the atria during ventricular systole. The closing of these valves also help build high pressure in the ventricles during ventricular systole which helps to push blood into the arteries

Question 8

function: Right ventricle

Answer 8

Recieves deoxygenated blood from right atrium and pumps deoxygenated blood into lungs via pulmonary arteries

Question 9

function: left ventricle

Answer 9

It recieves oxygenated blood left atrium and pumps oxygenated blood to all parts of the body except the lungs via aorta

Question 10

function: pulmonary artery

Answer 10

Carries deoxygenated blood from right ventricles to lungs

Question 11

function: pulmonary vein

Answer 11

Carries oxygenated from lungs to the left atrium of the heart

Question 12

function: aorta

Answer 12

Carries oxygenated blood from left ventricle to the body except for the lungs

Question 13

function: superior venacava

Answer 13

Carries deoxygenated blood from head to the right atrium

Question 14

function: inferior venacava

Answer 14

Carries deoxygenated blood from body to the right atrium

Question 15

function: semilunar valves

Answer 15

Valves present in the pulmonary artery & aorta preventing backflow of blood to ventricles when it relax

Question 16

function: tendons

Answer 16

They keep the tricuspid & bicupid valves from flipping over into the atria during ventricular systole

Question 17

Function: coronary artery

Answer 17

Supplies oxygenated blood to the cardiac muscles

Question 18

Coronary circulation

Answer 18

The coronary circulation supplies blood to the cardiac muscles
It splits into capillaries & exchange of materials takes place between the blood & tissues. The capillaries reunite to form veins which pour blood back into the right atrium through the coronary sinus
Blockage of the coronary vessels leads to heart attacks or coronary heart disease (CHD)

Question 19

Why the wall of left ventricle thicker than right ventricle: left ventricle

Answer 19

The walls of the left ventricle are much thicker as they have to exert greater pressure to pump blood to all parts of the body even to the head against the force of gravity

Question 20

Why the wall of left ventricle thicker than right ventricle: right ventricle

Answer 20

The right ventricles exert a much lower pressure as the lungs are close to the heart & pulmonary tissues are very delicate

Answer 21

High Bp in the pulmonary circulation will lead of pulmonary oedema causing the lungs to fill with tissue fluid.
This will cause the person to drown in their own fluids

Question 22

Cardiac cycle

Answer 22

The cardiac cycle is the rhythmic contract & relaxation of the atria & ventricles

Question 23

Systole

Answer 23

Contraction

Question 24

Diastole

Answer 24

Relaxation

Question 25

Atrial systole

Answer 25

Both ventricles relax simultaneously Both atria contracts simultaneously Lower pressure in each ventricle compared to each atrium above slightly opening atrioventricular valves The atria contract which forces blood to the ventricles

Question 26

Ventricular systole

Answer 26

Both atria relax simultaneously Both ventricle contract simultaneously Higher pressure in the ventricles compared to aorta & PA opens the semilunar valves AV valve close due to high press in the ventricles compared to the atria Blood pumped out via PA & aorta Atria are being refilled during this time

Question 27

Cardiac diastole

Answer 27

Ventricles & atria relax for a short time Higher pressure in the aorta & PA than the ventricles semilunar valve close Higher pressure in the venacava & PV than the atria resulting in the refilling of the atria Blood slowly oozes into ventricles from atria The cycle is now complete

Question 29

Cardiac cycle: elastic recoil of aorta

Answer 29

During ventricular systole the aorta is stretched due to the high pressure During complete diastole the aortic semilunar valve closes & the aorta walls recoil to maintain a high pressure This pressure helps to propel the blood forward in the arteries The elastic recoil of arteries can be felt as the pulse

Question 30

Cardiac cycle: elastic recoil of aorta ventricular contraction

Answer 30

1. Ventricle contracts 2. Semilunar valve opens 3. Aorta & arteries expand & store pressure in elastic walls

Question 31

Cardiac cycle: elastic recoil of aorta ventricular relaxation

Answer 31

1. Ventricle relaxes 2. Semilunar valve shuts preventing flow back into ventricle 3. Elastic recoil of arteries sends blood forward into rest of circulatory system