3.2 Transport in animals

Question 1

What are the 3 features circulatory systems have in common?

Answer 1

• they have a liquid transport medium that circulates around the body
• they have vessels that carry the transport medium
• they have a pumping mechanism to move the fluid around the system

Question 2

What are the 4 types of circulatory system?

Answer 2

1. Open circulatory system
2. Closed circulatory system
3. Single closed circulatory system
4. Double closed circulatory system

Question 3

What is an open circulatory system?

Answer 3

there are very few vessels to contain the transport medium and it is pumped straight from the heart into the haemocoel. found mainly in invertebrates

Question 4

What is insect blood called?

Answer 4

Haemolymph

Question 5

What is a closed circulatory system?

Answer 5

The blood is enclosed in blood vessels and does not come directly into contact with the cells of the body

Question 6

What is a single closed circulatory system and where are they found?

Answer 6

• the blood flows through the heart and is pumped out to travel all around the body before returning to the heart. The blood only travels once through the heart for each complete circulation of the body
• found in fish and annelid worms

Question 7

What is a double closed circulatory system?

Answer 7

involves two separate circulations. Blood is pumped to the lungs to pick up O and unload CO2 and then returns to the heart where it is then transported all over the body. The blood travels twice through the heart for each circuit of the body

Question 8

What do arteries do?

Answer 8

Carry blood away from the heart

Question 9

What do arterioles do?

Answer 9

link the arteries and the capillaries

Question 10

What are capillaries?

Answer 10

microscopic blood vessels that link the arterioles with the venules

Question 11

How are capillaries adapted for their role?

Answer 11

• provide a large surface area
• the total cross-sectional area of the capillaries is always greater than the arteriole supplying them so the rate of blood flow falls giving more time for gas exchange
• the walls are a single endothelial cell thick

Question 12

What do veins do?

Answer 12

carry blood towards the heart

Question 13

What does the pulmonary vein do?

Answer 13

carry oxygenated blood from the lungs to the heart

Question 14

What does the inferior vena cava do?

Answer 14

carry deoxygenated blood from the lower parts of the body back to the heart

Question 15

What does the superior vena cava do?

Answer 15

carry deoxygenated blood from the head and upper parts of the body back to the heart

Question 16

Do veins have a pulse?

Answer 16

no

Question 17

What do venules do?

Answer 17

link the capillaries with the veins

Question 18

What does blood consist of?

Answer 18

• plasma
• red blood cells
• white blood cells
• platelets

Question 19

What are the functions of the blood?

Answer 19

• transport of O2 and CO2
• transport of digested food
• transport of nitrogenous waste products
• transport of hormones
• transport of platelets to damaged areas
• transport of cells and antibodies involved in the immune response
• maintenance of body temperature and pH

Question 20

What is tissue fluid?

Answer 20

the solution surrounding the cells of most tissues, arriving via blood capillaries and being removed by the lymphatic vessels

Question 21

How is filtration pressure calculated?

Answer 21

filtration pressure = hydrostatic pressure - oncotic pressure

Question 22

Define oncotic pressure

Answer 22

The tendency of water to move into the blood by osmosis

Question 23

Define hydrostatic pressure

Answer 23

As the blood flows through the arterioles into the capillaries, it is still under pressure from the surge of blood that occurs every time the heart contracts. this is hydrostatic pressure

Question 24

Does tissue fluid have the same composition as plasma?

Answer 24

no it has almost the same but without red blood cells and plasma proteins

Question 25

What is lymph?

Answer 25

Tissue fluid that drains into the lymphatic system

Question 26

Does lymph have the same composition as tissue fluid and plasma?

Answer 26

No, similar but with less oxygen and fewer nutrients. It also contains fatty acids

Question 27

What is a major role of the lymphatic system?

Answer 27

defence mechanisms of the body

Question 28

How is oxygen transported around the body?

Answer 28

In haemoglobin in erythrocytes

Question 29

What is formed when oxygen binds to haemoglobin?

Answer 29

oxyhaemoglobin

Question 30

What is positive cooperativity?

Answer 30

the arrangement of the haemoglobin molecule means that as soon as one oxygen binds to a haem group, the molecule changes shape, making it easier for the next oxygen molecules to bind

Question 31

What is plotted in an oxygen dissociation curve?

Answer 31

percentage saturation haemoglobin is plotted against the partial pressure of oxygen

Question 32

What happens at low pO2?

Answer 32

few haem groups are bound to oxygen so haemoglobin does not carry much oxygen

Question 33

What happens at higher pO2?

Answer 33

more haem groups are bound to oxygen, making it easier for more oxygen to be picked up

Question 34

What happens at very high pO2?

Answer 34

haemoglobin becomes saturated so all the haem groups become bound