Unit 2.5 - Arteries, Capilaries + Veins

Question 1

How does blood circulate?

Answer 1

From the heart through the arteries to the capillaries then to the veins and back to the heart.

Question 2

What happens to blood pressure as blood moves away from the heart?

Answer 2

It decreases

Question 3

Describe the function of arteries

Answer 3

• carries blood away from the heart
• carries oxygenated blood (except for the pulmonary artery
• carries blood under high pressure

Question 4

Describe the structure of arteries

Answer 4

• Outside where is a type of supporting tissue called connective tissue containing elastic fibres which provide support
• Middle layer contains smooth-muscle with more elastic fibres the elastic rolls stretch and recoil to accommodate the surge of blood after each contraction of the heart
• The inner lining is endothelium
• The channel of the vessel ( lumen) is narrow

Question 5

Describe the structure and function of capillaries

Answer 5

Capillaries a low exchange of substances with tissue through their thin walls

Question 6

Explain the role of vasoconstriction and vasodilation

Answer 6

The smooth-muscle in the walls of the arteries contract or relax causing vasoconstriction or vasodilation to control blood flow

Question 7

Describe the function of veins

Answer 7

• Carries blood to the heart
• Carries deoxygenated blood (except pulmonary vein)
• Carries blood under low or negative pressure
• Contains valves which prevent the back flow of blood

Question 8

Describe the structure of veins

Answer 8

• Have less connective tissue than arteries (containing elastic fibres)
• Have thin walls (have less muscular tissue than arteries)
• Have wide lumen

Question 9

Describe the exchange of materials between tissue fluid and cells through pressure filtration

Answer 9

Pressure filtration causes plasma to pass through capillary walls into the tissue fluid surrounding the cells. Tissue fluid supplies cells with glucose, oxygen and other substances. Carbon dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be extracted much of the tissue fluid returns to the blood

Question 10

What do you lymphatic vessels do?

Answer 10

Absorb excess tissue fluid and return it as lymph to the circulatory system

Question 11

Talk about the different between tissue fluid and blood plasma

Answer 11

Tissue fluid and blood plasma or similar and composition with the exception of plasma proteins which are too large to be filtered through the capillary walls