Circulatory systems

Question 0

What is the advantage of a closed circulatory system?

Answer 0

-the blood travels faster; therefore the blood system is more efficient at delivering substances around the body.

Question 1

What is a closed circulatory system? (2)

Answer 1

• blood is enclosed within tubes

- this generates higher blood pressures as is the blood is forced along narrow channels

Question 2

What kind of animals have a closed circulatory system? (2)

Answer 2

• Generally larger in size

- Vertebrates

Question 3

NOTE: a closed circulatory system is NOT a single circulatory system. What 2 types of closed circulatory systems are there?

Answer 3

• Single

- Double

Question 4

Example of where a single circulatory system is found.

Answer 4

In fish

Question 5

Describe the single circulation system in fish. (3) What are the two diffusion processes that take place?

Answer 5

• heart pumps deoxygenated blood to gills
• gaseous exchange takes place here; *diffusion of CO2 from blood into the water that surrounds the gills *diffusion of O2 from this water into the blood
• blood leaving the gills then flows round the rest of the body before returning to the heart

Question 6

Examples of where a double circulatory is found.

Answer 6

• Birds

- Mammals

Question 7

Describe the double circulatory system.

Answer 7

• Right ventricle pumps deoxygenated blood to the lungs where it receives oxygen
• Oxygenated blood then returns to the heart to be pumped to the rest of the body (by the left ventricle)

Question 8

NOTE: single circulatory system

Answer 8

Blood flows through the heart once for each complete circuit of the body.

Question 9

NOTE: double circulatory system
why?
allowing what?

Answer 9

Blood flow through the heart twice for each complete circuit of the body.
Because the heart gives the blood returning from the lungs an extra pump to reduce the time taken for the blood to circulate round the whole body. Allowing birds and mammals to have a high metabolic rate.

Question 10

Open circulatory system

• blood circulates in…?
• simple heart pumps…?
• when the heart relaxes…?

Answer 10

• blood circulates in large open spaces
• a simple heart pumps blood out into cavities surrounding the animal’s organs.
• when the heart relaxes- blood is drawn from the cavity back into the heart thorough small valved openings.

Question 11

The heart maintains a high pressure of oxygenated blood in the arteries to the body. Explain how a double circulation is important in bringing this about. (3)

Answer 11

Double circulatory system provides 2 types of pressures; high and low.

• low pressure for the blood that travels to the lungs. (In order to protect capillaries).
• when the blood returns from the lungs under low pressure, it is not enough for the blood to travel around the body.
• a second pump increases the blood pressure in the arteries.

Question 12

Why does a small insect not need blood vessels to transport its blood around the body. (3)

Answer 12

• low metabolic rate
• diffusion rate (of glucose and oxygen) is sufficient for the insect.
• large surface area to volume ratio.