Mass Transport In Animals

Question 1

What are the main blood vessels and what do they do?

Answer 1

Pulmonary artery - carries deoxygenated blood from the right ventricle to the lungs
Pulmonary vein - carries oxygenated blood away from the lungs to the left atrium
Vena cava - allows deoxygenated blood from the body to enter the heart at the right atrium
Aorta - carries oxygenated blood out of the heart from the left atrium and to the rest of the body
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Question 2

How does the structure of arteries relate to its function?

Answer 2

Arteries carry oxygenated blood away from the heart
Thick muscular walls - withstand high pressure
Thick elastic layers - allows walls to stretch and recoil to keep in line with the pulsating flow of the blood
Smooth muscle - reduces friction and creates less restriction for the blood
Wall is very thick - prevents it from bursting under pressure

Question 3

How does the structure of the arterioles relate to its function?

Answer 3

Arterioles filter off from arteries and carry blood from them to the capillaries
Muscle layer is thicker - movement of blood into the capillaries can be controlled
Elastic layer is thinner - blood pressure is lower

Question 4

How does the structure of veins relate to its function?

Answer 4

Transport deoxygenated blood from the body back to the heart.
Thin muscle layer and elastic layer - as constriction is not needed and blood is under low pressure
Veins have valves - prevents the back flow of blood
Wide lumen - Maximises the volume of blood that is carried to the heart

Question 5

How does the structure of the capillaries relate to its function?

Answer 5

Exchange substances between the blood and body tissues - site of metabolic exchange
One cell thick - allows for rapid diffusion of substances
Many capillaries and they are highly branched - large surface area for the exchange of substances
Extremely narrow - increases rate of diffusion

Question 6

Describe the function of tissue fluid

Answer 6

Tissue fluid formed at the arterial end of the capillaries and forced into tissue cells due to hydrostatic pressure (ultrafiltration) tissue fluid is transferred back into the blood at the venous end due to oncotic pressure. Transfers molecules such as oxygen and glucose to the tissue cells. Waste molecules from the tissue cells such as CO2 pass into the tissue fluid.