B3.2.1 The blood system

Question 1

What does the circulatory system do?

Answer 1

The circulatory system transports substances around the body.

Question 2

What does the circulatory system consist of?

Answer 2

• The heart
• The blood
• Veins
• Arteries
• Capillaries

Question 3

What is a double circulatory system?

Answer 3

There is one circulation solely for the lungs (in order to oxygenate the blood) and one for the rest of the body.

Question 4

Why is a double circulatory system important?

Answer 4

It can create higher pressures to transport blood further, allowing mammals to be bigger.

e.g. humans

Question 5

What is the heart mainly made of?

Answer 5

Muscle tissue

Question 6

Which side of the heart pumps blood to the lungs?

Answer 6

The right side of the heart.

Question 7

Which side of the heart pumps blood the the rest of the body?

Answer 7

The left side of the heart.

Question 8

Name the 4 chambers that make up the heart.

Answer 8

Left atrium
Left ventricle
Right atrium
Right ventricle

Question 9

What direction do veins carry blood?

Answer 9

Towards the heart

Question 10

What direction do arteries carry blood?

Answer 10

Away from the heart

Question 11

What separates the atrium and ventricle and what does it do?

Answer 11

Valves - prevent the back flow of blood + make sure blood flows in the right direction.

Question 12

What is the vena cava?

Answer 12

The major vein that carries deoxygenated blood to the right atrium from the body tissues.

Question 13

What is the pulmonary artery?

Answer 13

The major blood vessel that carries deoxygenated blood to the lungs from the right ventricle.

Question 14

What is the pulmonary vein?

Answer 14

The major blood vessel that carries oxygenated blood from the lungs to the left atrium.

Question 15

What is the aorta?

Answer 15

The major artery that carries oxygenated blood from the left ventricle to the body tissues.

Question 16

Describe the flow of blood through the heart.

Start with deoxygenated blood entering.

Answer 16

Deoxygenated blood enters the RIGHT ATRIUM through the VENA CAVA.

The blood is pumped into the the RIGHT VENTRICLE through a VALVE.

The blood is pumped to the LUNGS through the PULMONARY ARTERY.

Oxygenated blood enters the LEFT ATRIUM through the PULMONARY VEIN.

The blood is pumped into the the LEFT VENTRICLE through a VALVE.

The blood is pumped to the body tissues through the AORTA.

Question 17

If someone has faulty heart valves, what are the two options of replacement?

Answer 17

Biological valves (donor)

Mechanical valves (man made)

Question 18

Give an advantage and a disadvantage of mechanical valves.

Answer 18

Pro - Very strong and durable - able to last a lifetime

Con - Damage red blood cells as they pass through the open valves

Question 19

When are artificial heart used and why?

Answer 19

Only used as a short-term measure to keep patients alive until a biological donor heart can be found.

They are not successful in the long term and are prone to blood clotting.

Question 20

Describe the properties of arteries.

Answer 20

• Thick walls - to resist the high pressure of the blood
• Thick layer of elastic fibres - to allow the artery to stretch and recoil when a surge of blood passes through it
• Muscular wall - to allow blood to be diverted to where it is needed in the body
• Narrow lumens

Question 21

Describe the properties of veins

Answer 21

• Thin walls as they have blood with a lower pressure flowing through them
• One-way valves in them to prevent blood flowing back in the opposite direction
• Wide lumens

Question 22

What is the lumen?

Answer 22

The central cavity in a vein / artery

Question 23

What are stents?

Answer 23

Metal grids which can be inserted into an artery to maintain blood flow by keeping the artery open.

Question 24

Why could someone develop narrow lumens and require a stent?

Answer 24

Patients who have heart disease - the build-up of fatty deposits within the wall of the artery.

Question 25

What is used to insert a stent?

Answer 25

A catheter with a balloon attached to it.

Question 26

What are capillaries?

Answer 26

The smallest type of blood vessel that are adapted to allow the effective exchange of substances between the blood and the tissues of the body.

Question 27

How are capillaries adapted to be a good exchange surface?

Answer 27

They are one cell thick which gives a short diffusion pathway.

Question 28

What is tissue fluid?

Answer 28

A fluid that leaves the blood through the capillaries containing glucose, oxygen and amino acids.

Question 29

How does a cell get what it needs from tissue fluid?

Answer 29

Diffusion - the substances are always being used up in the cell so a concentration gradient is maintained.

Question 30

What substances leave the cell to be absorbed into the blood?

Answer 30

Carbon dioxide and urea.