The Heart & Blood Vessels Flashcards
What are the three coats (layers) of the blood vessels?
1) Tunica Intima
2) Tunica media
3) tunica externa/adventitia
what is the tunica intima made of?
- endothelium= simple squamous
- loose CT
- Lamina- internal elastic membrane (sheet of protein elastin)
what is a unique feature of veins, but more specifically the Tunica Intima?
it has one way valves (move blood towards the heart)
what is the Tunica Media composed of?
- smooth muscle
- CT
- elastic fibers
what is the Tunica Externa/adventitia composed of?
- external lamina
- CT
- Vasa Vasorum= small blood vessels that supply the walls of very large arteries
What 3 types of arteries do we need to know for the exam?
1) Elastic arteries- largest arteries (thin walls), come from heart
2) Muscular arteries- medium sized arteries in tissue, drain from elastic artieries
3) Arterioles- smallest arteries, drain from muscular arteries
what are the smallest blood vessels we need to know about?
Capillaries
Which blood vessels return the blood to the heart?
Veins (small, medium, large)
give an example of a low permeability capillary
Blood-Brain-Barrier (BBB)
what are 3 distinct features of the BBB
1) capillaries have complete tight junctions
2) no intercellular clefts are present
3) vital molecules pass through
what 3 substances are able to permeate the BBB?
1) oxygen
2) carbon dioxide
3) anesthetics (and other drugs)
what is a sinusoid?
a small blood vessel that is a type of capillary. Sinusoids are actually classified as a type of open pore capillary or “discontinuous”
what is meant by “discontinuous” when describing sinusoids?
-Intercellular clefts are WIDE or LEAKY (they also have a wide diameter and a twisted course)
where are Sinusoids found?
in bone marrow or in the Spleen
what is the function of valves found in veins?
-prevent back flow (blood propelled back towards the heart by a muscle pump)
