Blood Vessels and their Functions

Question 1

What is the structure of the following:
-Artery?
-Capillary?
-Vein?

Answer 1

=Artery
-Tough fibrous outer layer
-Muscle layer
-Elastic layer
-Thin inner lining
-Lumen

=Capillary
-Walls made mostly of lining layer
-Numerous and highly branched
-Narrow diameter
-Narrow lumen (One red blood cell at a time)
-Spaces between lining cells (Endothelial cells)

=Vein
-Thin muscle layer
-Thin elastic layer
-Valves

Question 2

What is the function of the following:
-Artery?
-Capillary?
-Vein?

Answer 2

=Artery
-Carry high pressure blood away from the heart and into arterioles

=Capillaries
-Branch off of arterioles which branch off of arteries
-Carry blood close to every cell in the body

=Veins
-Carry deoxygenated lower pressure blood from capillaries back to the heart

Question 3

How is tissue fluid formed?

Answer 3

-Hydrostatic pressure is created by the pumping of blood at the arterial end of the capillaries
-This causes tissue fluid to move out of the blood plasma
-This movement is however opposed by (1) Hydrostatic pressure outside the capillaries (2) Lower water potential of the blood cause water to move back into the blood within the capillaries
-The overall movement is still moving tissue fluid out of the capillaries
-Ultrafiltration occurs (Only enough force for small molecules to leave capillaries occurs)
-Tissue fluid is eventually forced back into the circulatory system by external hydrostatic pressure