| What are the different walls of arteries and veins | Tunica intima → next to the lumen
Tunica media → intermediate
Tunica adventitia → outer layer |
| What are the 3 types of arteries | Elastic conducting arteries → widest
Muscular distributing arteries → intermediate diameter
Arterioles → narrowest |
| What happens when blood flow is cut off to the limb and when it returns | When there is no blood flow, metabolites accumulate, so arterioles dilate maximally
When flow is returned, resistance is very low so flow is very high but high flow washes away the metabolites and so smooth muscle constricts again |
| What are the 3 types of capillaries | Continous Capallaries --> most common type, nervous, muscle etc. locations
Fenestrated capillaries --> gut, endocrine glands and renal glomerulus
Discontinous --> In liver, spleen and bone marrow, generally wider and slower blood flow |
| What are some examples of vasodilator molecules and their mode of action | H+
K+
Adenosine
These act as relax vascular smooth muscle --> vasodilation |
| An increase in metabolism leads to what in the bloodstream | If metabolism increases more metabolites are produced
So concentration increases, vasodilation occurs
Vasodilation leads to an increase in flow
Increased flow washes away the metabolites and more metabolism leads to more blood flow |
| What Vasomotor tone | Tonic contraction of smooth muscle known as vasomotor tone
Increases known as vasoconstriction |
| Factors affecting contraction of vascular smooth muscle : | Vasomotor tone mostly produced by the sympathetic branch of the autonomic nervous system
This tone is antagonised by vasodilator factors
The actual resistance determined by balance between the two |
