The Circulatory System

Question 1

Multicellular organisms have a ——- surface are to volume ratio

Answer 1

Low

Question 2

Define a circulatory system

Answer 2

a specialised transport system that carries raw materials from specialised exchange organs to their body cells

Question 3

What is the circulatory system made from

Answer 3

The heart and blood vessels

Question 4

What does blood transport around the body?

Answer 4

• respiratory gases
• products of digestion
• metabolic wastes
• hormones

Question 5

There are two circulatory systems, describe what each one does

Answer 5

1. Heart transports deoxygenated blood the heart to lungs, where it associates oxygen, and then takes it back to the heart
2. Blood vessels go to the rest of the body (oxygenated vessels)

Question 6

Name the different blood vessels

Answer 6

1. Arteries
2. Arterioles
3. Veins
4. Capillaries

Question 7

What is the role of arteries?

Answer 7

To carry oxygenated blood (minus the pulmonary artery) to the rest of your body

Question 8

List the feature of the arteries

Answer 8

• thick and muscular walls
• have elastic tissues to help maintain a high pressure
• endothelium is folded to allow artery to stretch
• arteries divide into arterioles which create a branch network throughout your body

Question 9

How is the pulmonary artery different to other arteries?

Answer 9

It carries deoxygenated blood to the lungs, whereas other arteries take oxygenated blood to the rest of your body cells

Question 10

What is the role of veins?

Answer 10

To take deoxygenated blood back to the heart under low pressure

Question 11

List the features of the veins

Answer 11

• have a wide lumen
• little elastic or muscle tissue
• contain valves

Question 12

How is the pulmonary vein different to other veins?

Answer 12

As the pulmonary vein carries oxygenated blood to the heart from the lungs. Whereas other veins carry deoxygenated blood back to the heart from the body

Question 13

What is the role of the capillaries?

Answer 13

It is to transport oxygenated blood to cells near exchange tissues, they are where substances are exchanged between blood and body tissues at the capillaries

Question 14

What do arterioles branch into?

Answer 14

They branch into capillaries

Question 15

List the features of capillaries

Answer 15

• one cell thick, and are found near cells located at exchange tissues, creating a short pathway
• there are large number of capillaries to increase gas exchange, creating capillary beds

Question 16

What is tissue fluid formed from?

Answer 16

It is formed from blood

Question 17

Define tissue fluid

Answer 17

A watery liquid that contains glucose, amino acids, fatty acids, ions in solution and oxygen,it is made from blood plasma

Question 18

Cells take in —— and —— from tissue fluids and release ——— ——— into it

Answer 18

• oxygen
  -nutrients
• metabolic waste

Question 19

What is pressure filtration?

Answer 19

It is where in the capillary bed, substances move out of the capillaries to the tissue fluid

Question 20

What happens to excess tissue fluid?

Answer 20

Excess tissue fluid is drained into the lymphatic system, which transports excess fluid from the tissues and dumps it back into the circulatory system

Question 21

Describe pressure filtration

Answer 21

1. At the start of the capillary bed, near the arteries, the hydrostatic pressure inside the capillaries is greater than hydrostatic pressure in the tissue fluid
2. This creates an outward pressure, forcing fluids out of the capillary cells
   This forms tissue fluid
3. As the fluid leaves hydrostatic pressure reduces in the capillaries meaning pressure is the lowest at the veins than in the tissue fluid
4. Makes water renter the capillaries from the tissue fluid at the Venice end via osmosis