3.2 - Transport in Animals

Question 1

What are OPEN closed circulatory systems?

Answer 1

The blood is not always held in vessels.
The tissue fluid is bathed within the blood.
The flow of blood comes from body movement or a pumping organ.

Question 2

What are CLOSED circulatory systems?

Answer 2

Blood is always held in vessels

Question 3

What are SINGLE circulatory systems?

Give an example of an organism that has this circulatory system.

Answer 3

Blood flows the heart once per circuit

Fish have single circulatory systems

Question 4

State the pathway that the blood takes in a single circulatory system.

Answer 4

Heart → Gills → Body → Heart

Question 5

What are DOUBLE circulatory systems?

Give an example of an organism that has this circulatory system.

Answer 5

Blood flows through the heart twice per circuit

Mammals/amphibians have double circulatory systems

Question 6

What is the difference between PULMONARY and SYSTEMIC circulation?

Answer 6

Pulmonary circulation is the circulation that carries blood to the lungs to pick up oxygen.
Systemic circulation is the circulation that carries blood which carries the oxygen and nutrients around the body to the tissues.

Question 7

State the pathway that the blood takes in the double circulatory system.

Answer 7

Heart → Body → Heart → Lungs → Heart

Question 8

Give 4 reasons why double circulatory systems are more effective than single circulatory systems.

Answer 8

1. Blood pressure can be raised after passing through the lungs
2. Blood flows more quickly to the tissues
3. Provides required nutrients for respiration
4. Systemic circulation can have a higher pressure than pulmonary

Question 9

What is the order of the blood vessel network?

Answer 9

(Heart) → Arteries → Arterioles → Capillaries → Venules → Veins → (Heart)

Question 10

Which direction do arteries carry the blood?

Answer 10

AWAY from the heart

Question 11

What level of pressure is the blood being carried by the arteries in?

Answer 11

HIGH pressure, because it needs to transport blood from the heart to all the way around the body

Question 12

State 5 features of arteries that make them suitable for the high pressure of blood it delivers.

Answer 12

1. SMALL LUMEN: Maintains the high pressure
2. SMALL ENDOTHELIUM (wall): Helps keep the blood flow going, also folded to allow changes of blood flow
3. TUNICA INTIMA: thin layer of elastic fibres, allows for stretching and recoiling
4. TUNICA MEDIA: contains smooth muscle
5. TUNICA ADVENTITIA: thick layer of collagen and elastic tissue (helps with strength/recoil)

Question 13

What are arterioles? (4)

Answer 13

• Slightly smaller vessels connected to arteries
• Still has a high pressure, but not as high as arteries
• They’re just layers of smooth muscle
• Can contract to constrict the lumen diameter, increasing resistance to flow - this can target active tissues

Question 14

What are capillaries? (3)

Answer 14

• 1 squamous cell thick (endothelium)
• small lumen
• leaky, enables the formation of tissue fluid

Question 15

What are venules? (3)

Answer 15

• consists of collagen
• consists of muscle + elastic tissue
• endothelium

Question 16

What direction do veins carry the blood?

Answer 16

TOWARDS the heart

Question 17

What are veins? (3)

Answer 17

• walls do not need to be thick
• still contain collagen, smooth muscle, elastic tissue, e endothelium
• contain VALVES which prevent backflow