Arteries, Veins and Capillaries Flashcards
What is central cavity of a blood vessel called
Lumen
What is the lumen lined by
Endothelium
What is the endothelium surrounded by
Layers of tissue, the outer layer is connective tissues and the inner layer is smooth muscle
What do both the smooth muscle and connective tissues contain
Elastic fibres
What do elastic fibres enable
The artery wall to stretch and recoil, accommodating the surges in blood pressure
What aspect of the arteries controls blood flow
Vasodilation and vasoconstriction
What is vaso(constriction/dilation) controlled by
The autonomic nervous system
Differences in thickness of arteries and veins
Veins have thinner smooth muscle and wider lumen
How is blood transported between tissue fluid
From artérioles to venules, passing through a dense network of capillaries
How are capillarie structured
One cell thick, a layer of endothelium
How much of blood is made up of plasma
55%
What is plasma
A watery yellow fluid containing dissolved substances such as glucose, amino acids, blood cellsX platelets and plasma proteins
What is pressure filtration
When blood enters the capillaries from the artérioles it is at very high pressure. This causes much of the plasma to be squeezed out of the thin walls into the tissue fluid surrounding the capillaries.
What is the only difference between tissue fluid and plasma
Plasma proteins
Do plasma proteins get squeezed out
No, they are too big to be filtered through capillary walls
