The Heart

Question 1

Function of heart

Answer 1

to pump blood around the body. It is made of a special type of muscle called cardiac muscle.

Question 2

Cardiac muscle

Answer 2

The walls of the heart are composed of cardiac muscle which has its own inherent rhythm and does not get tired. it contracts and relaxes regularly, throughout life.

Question 3

divisions

Answer 3

The heart is divided into four chambers. The two on the right contain deoxygenated blood and are completely separated from the two on the left which contain oxygenated blood, by the septum.

Question 4

atria

Answer 4

top two chambers, have thin walls and they collect blood entering the heart.

Question 5

ventricles

Answer 5

The bottom two chambers, have thick walls and they pump blood out of the heart.

Question 6

valves

Answer 6

present between each atrium and ventricle and in the pulmonary artery and aorta as they leave the ventricles to ensure that blood flows through the heart in one direction.

Question 7

pulmonary artery

Answer 7

carries deoxygenated blood to the lungs

Question 8

aorta

Answer 8

carries oxygenated blood to the body

Question 9

left atrium

Answer 9

collects oxygenated blood from the lungs

Question 10

pulmonary veins

Answer 10

carry oxygenated blood from the lungs

Question 11

semi-lunar valves

Answer 11

prevent the backflow of blood into the ventricles when they relax

Question 12

bicuspid valve

Answer 12

prevents the blood flowing
back into the atrium when
the ventricle contracts..has two parts

Question 13

tendons

Answer 13

prevent the valve turning inside out

Question 14

left ventricle

Answer 14

thicker walled than the right ventricle to pump oxygenated blood longer distances around the body

Question 15

septum

Answer 15

thick, muscular, separates the left and right ventricles

Question 16

cardiac muscle

Answer 16

thick, own inherent muscle

Question 17

right ventricle

Answer 17

pumps deoxygenated blood to
the lungs

Question 18

tricuspid valve

Answer 18

prevents the blood flowing
back into the atrium when
the ventricle contracts…has three parts

Question 19

posterior vena cava

Answer 19

carries deoxygenated
blood from the body

Question 20

right atrium

Answer 20

collects
deoxygenated blood from
the head and body

Question 21

anterior vena cava

Answer 21

carries deoxygenated
blood from the head

Question 22

name of diagram

Answer 22

Longitudinal section through the human heart showing the function of the parts

Question 23

Atrioventricular valves

Answer 23

the valve between the left atrium and the left ventricle, and the other between the right atrium and the right ventricle

Question 24

systole

Answer 24

the heart beats as the cardiac muscles in its walls contract and relax. When they contract, the heart becomes smaller, squeezing blood out. This is called systole.

Question 25

diastole

Answer 25

when they relax, the heart becomes larger, allowing the blood to flow into the atria and ventricles. This is called diastole.

Question 26

pacemaker/sinoatrial node

Answer 26

the heart beat begins in the wall of the right atrium, then spreads throughout the heart. The heart beats on average 75 times per minute. This rate is maintained by a group of specialised cardiac muscle cells in the right atrium called the pacemaker and can be modified by nerve impulses,e.g. the rate increases with exercise.

Question 27

Diastole; all muscles are relaxed blood flows into the heart

Answer 27

The atria and ventricles relax together (diastole), the semi-lunar valves close, the atria fill up with blood from the anterior and posterior vena cavae and pulmonary vein, and the blood flows into the ventricles. This takes 0.4 seconds.

Question 28

atrial systole

Answer 28

The muscles of the atria contract together (atrial systole) forcing any remaining blood into the ventricles. the semi-lunar valves remain shut. The valves in the vein are shut by the pressure of blood, stopping the backflow of blood. This takes 0.1 seconds.

Question 29

ventricular systole

Answer 29

The semilunar valves are forced open by the pressure of the blood.The ventricles contract together, the tricuspid and bicuspid valves close and blood is forced into the pulmonary artery and aorta. This takes 0.3 seconds.

Question 30

In the pulmonary circulation

Answer 30

,blood travels from the right ventricle through the pulmonary artery to the lungs to pick up oxygen and lose carbon dioxide, i.e. it becomes oxygenated. It then travels back via the pulmonary vein to the left atrium

Question 31

In the systemic (body) circulation

Answer 31

the blood travels from the left ventricle through the aorta to the body where it gives up oxygen to the body cells and picks up carbon dioxide, i.e. it becomes deoxygenated. It then travels back via the anterior or posterior vena cava to the right atrium.

Question 32

double circulatory system

Answer 32

because blood passes through the heart twice per circuit.

Question 33

Why is a double circulatory system necessary

Answer 33

because blood loses pressure when it passes through the lungs, so it goes back to the heart to be given enough pressure to reach body organs to supply them with oxygen. As it loses pressure passing through organs, the blood goes back to the heart again to be given enough pressure to reach the lungs to get rid of waste carbon dioxide and pick up more oxygen.