10. cardiovascular system

Question 1

the heart and its function

Answer 1

the heart is a muscular pump that has two functions. there is two sides to the heart;
1. the right hand side pumps blood to the lungs.
2. the left handside pumps blood to the rest of the body.
As the right hand side is only pumping blood to the lungs it is not as muscular as the left which pumps blood to the entire body.

Question 2

the valves and chambers of the heart

Answer 2

The heart contains valves which prevent the blood flow from back flowing in the wrong direction.

The heart has 4 chambers; 2 atrium, 2 ventricles.

Question 3

Direction of blood flow through the heart

Answer 3

• Blood returns to the heart via the main vein called the vena cava, it enters the right atrium, passes through the tricuspid valve, into the right ventricle.
• It then passes through the semi lunar valve and enters the pulmonary artery to the lungs for gas exchange (CO2 out and O2 in).
• The blood then enters the pulmonary vein and returns to the heart entering the left atrium, it then passes through a biscuslar valve into the left ventricle.
• It is then pumped through the other semi-lunar valve into the aorta (main artery).
• Then the oxygen is transported throughout the body.

Question 4

5 main blood vessels

Answer 4

arteries - all go away from the heart

arterioles - smaller branches

capillaries - smallest blood vessels, they are only one cell thick, exchange of gases/nutrients happen here.

venules - smaller branches of vien

vein - all return to the heart.

Question 5

arteries

Answer 5

a very thick muscular wall, elastic to withstand pressure of blood being pumped from the heart. The lumen is narrow.

Question 6

veins

Answer 6

a very thin muscle layer, larger lumen.
contains valves to prevent backflow of blood.

Question 7

capillaries

Answer 7

smallest blood vessels, they are only one cell thick, exchange of gases/nutrients happen here.

Question 8

major arteries and veins

Answer 8

lungs - pulmonary artery - pulmonary vein

kidney - renal artery - renal vein

heart - coronary artery - coronary vein

liver - hepatic artery - Hepatic vein.
(is weak as
it has 3 blood
vessels )

Question 9

lungs

Answer 9

• are the mammalian organs for gas exchange.
• they have million of alveoli (air sacs)

Question 10

alveoli

Answer 10

alveoli increase surface area and allow efficient gas exchange.
When breathe in air passes down the trachea, bronche, bronchioles before reaching the alveoli.
The trachea is held down by incomplete rings of cartilage.

Question 11

what is gas exchange

Answer 11

gas exchange is the process by which oxygen from the lungs enters the bloodstream and carbon dioxide in the bloodstream is lost to the lungs.