Unit 2-KA5 Flashcards
Give the name of the central space or cavity in a blood vessel
Central lumen
Name the layer of cells that forms the inner lining of a blood vessel
Endothelium
Define an artery
A blood vessel that carries blood away from the heart
Define a vein
A blood vessel that carries blood back to the heart
Explain why veins require valves
Valves prevent the backflow of blood back to the heart at low pressure
Give two structural differences between an artery and vein
Artery-
doesnt have valves
relatively narrow lumen
thicker muscular wall than vein
Vein-
has valves
relatively wide lumen
thinner muscular wall than artery
Describe the structure and function of a capillary
Capillary-
wall one cell thick
Allows the exchange of substances with tissues
Explain the process of pressure filtration in the capillary beds
Blood in the arteries is at a higher pressure than in capillary bed, pressure filtration causes the formation of tissue fluid
Describe how tissue fluid differs from blood plasma
Tissue fluid is similar to blood plasma but doesn’t contain plasma proteins
Describe the role of tissue fluid
Tissue fluid constrains glucose/oxygen/dissolved substances that supply the tissues with all their requirements
Contain carbon dioxide/metabolic waste to be excreted
Describe how tissue fluid renters the capillaries at the venue end of the capillary bed
re-enters capillaries by osmosis
Describe the role of lymph vessels
Excess tissue fluid enters the lymph vessels and is returned to the circulatory system
Explain the importance of vasoconstriction and vasodilation
Vasoconstriction/Vasodilation allows the changing demands of the body’s tissues to be met.
During exercise -
Muscle arterioles vasodilate-increase blood flow
Arterioles supplying the abdominal organs vasoconstrict-reduce blood flow
