Cardiac Cycle

Question 1

Arteries structure and function

Answer 1

Carries blood away from the heart and into arterioles.
Muscle layer thicker than veins meaning that smaller arteries can be constricted and dilated to control volume of blood passing through
Elastic layer thick compared with veins
Important blood pressure is kept high in arteries if blood is to reach extremities of the body.
Elastic wall stretched at each beat of the heart and springs back when relaxes diastole
Overall thickness stops vessel bursting under pressure
No valves because blood in constant high pressure so does not tend to flow backwards

Question 2

Veins structure and function

Answer 2

Muscle layer relatively thin because carry blood away from tissues so constriction and dilation cant control flow of blood
Elastic layer is thin low pressure will not cause them to burst
Overall thickness is small pressure is too low to create risk of bursting aids flow of blood by allowing them to be flattened easily.
Valves at intervals throughout to ensure blood does not flow backwards

Question 3

Capillary structure and function

Answer 3

Exchange of metabolic materials such as o2 co2 and glucose between blood and cells of the body
Walls consist mostly of the lining layer making them extremely thin so that diffusion path between blood and cells is short for exchange
Numerous and highly branched providing a large surface area for exchange
Narrow diameter so permeate tissues meaning short diffusion pathway
Narrow lumen red blood cells squashed against side of capillary bringing them close to cells in body for exchange short diffusion distance
Spaces between the endothelial cells allowing wbc to leave and deal with infections

Question 4

Blood vessels

Answer 4

Arteries carry blood away from heart
Arterioles smaller arteries controlling blood flow from arteries to capillaries
Veins carry blood from capillaries back top the heart