KA5 - Pathway Of Blood

Question 1

Explain the pathway of blood

Answer 1

Blood circulates from the heart through the arteries to the capillaries then to the veins and back to the heart.

Question 2

What happens to blood pressure as the blood moves away from the heart?

Answer 2

It decreases

Question 3

What are the 3 main types of blood vessels in the circulatory system?

Answer 3

Arteries
Veins
Capillaries

Question 4

What is the name given to the central channel through which blood flows in a blood vessel?

Answer 4

The central lumen

Question 5

What surrounds the central lumen?

Answer 5

The endothelium lining

Question 6

What is the function of arteries?

Answer 6

To carry blood away from the heart at high pressure

Question 7

Describe the structure of an artery(4)

Answer 7

1. Narrow central lumen
2. The endothelium lining surrounding the central lumen
3. Middle layer connecting smooth muscle to elastic fibres
4. Thick outer layer of connective tissues containing more elastic fibres

Question 8

Why must arteries have elastic walls?

Answer 8

To accommodate the surge of blood after each contraction of the heart

Question 9

What is vasodilation

Answer 9

During exercises, arteries leading to working muscles undergo vasodilation. The central lumen becomes wider allowing for an increased blood flow to the muscles involved.

Question 10

What is vasoconstriction?

Answer 10

At the same time, arteries leading to abdominal muscles undergo vasoconstriction. The central lumen becomes narrower, reducing blood flow to these muscles for a short time.

Question 11

What is the function of capillaries

Answer 11

To allow the exchange of substances with tissues

Question 12

How does the structure of capillaries enable them to carry out its function?

Answer 12

Their walls are only one cell thick allowing substances to diffuse with ease

Question 13

What is the function of veins?

Answer 13

To carry blood towards the heart at low pressure

Question 14

Describe the structure of a vein(5)

Answer 14

1. Wide central lumen
2. The endothelium lining surrounding the central lumen
3. A thinner muscular wall than arteries
4. A thin outer layer of connective tissue containing elastic fibres
5. Valves to prevent the back flow of blood

Question 15

What are the 3 components of blood?

Answer 15

Red blood cells
White blood cells
Plasma

Question 16

What does plasma transport as well as red and white blood cells?

Answer 16

Glucose 
Oxygen
Carbon dioxide 
Fat 
Protiens

Question 17

What is pressure filtration?

Answer 17

Pressure filtration is the process by which plasma passes through the capillary walls into the tissues fluid surrounding the cells

Question 18

What happens during pressure filtration?

Answer 18

Tissue fluid provides cells with useful substances which as glucose and oxygen. Carbon dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be removed by the body.

Much of the fluid returns to the blood at the venous end of the capillary by osmosis.

Question 19

What is the name given to excess tidier fluid?

Answer 19

Lymph

Question 20

What happens to the lymph?

Answer 20

It is absorbed by lymphatic vessels which return it to the circulatory system