Blood Vessels Flashcards
(32 cards)
What are the three layers of veins and arteries?
The tunica intima, tunica media, and tunica externa
The diameter of the lumen is wider in veins or arteries?
Veins
What is in the tunica intima?
Endothelium, subendothelial layer, internal elastic membrane (in arteries)
What is in the tunica media?
smooth muscles and elastic fibers as well as more external elastic membrane (in arteries)
What is in the tunica externa?
It is rich in collagen fibers and has vasa vasorum which are tiny blood vessels that serve the heart wall.
What do veins have that arteries don’t?
Valves
What is the makeup of a capillary?
A basement membrane outside of endothelial cells
What are the three types of arterial vessels? What are their characteristics?
Elastic Arteries are thick walled, large diameter, and are close to the heart
Muscular arteries distribute blood to organs and have more smooth muscle than elastin due to a more even pressure
Arterioles generally have a tunica media of entirely smooth muscle and determine which capillary beds are flushed
What substance is found a lot in elastic arteries?
Elastin
What are the three types of capillaries? Where are they found?
Continuous capillaries (least leaky), skin, brain, muscles
Fenestrated Capillaries, small intestine, kidneys, endocrine
Sinusoidal capillaries (most leaky), liver, bone marrow
What is microcirculation?
It is the flow of blood from an arteriole to a venule through a capillary bed
What is a true capillary
An actual exchange vessel
What are some factors aiding venous return?
- Venous valves plus the muscular pump
- The respiratory pump (decrease pressure in thoracic cavity)
- Sympathetic vasoconstriction
What is the formula for pulse pressure?
Systolic P - Diastolic P
What is the formula for MP?
Diastolic + 1/3 pulse pressure
How is resistance measured?
Proportional to = Length*viscosity / radius ^ 4
Where is most blood found?
The venous system
Why are pressure points called that?
They are areas where when pressure is applied it closes down the artery.
How would one treat short term and long term blood pressure issues?
Short term would deal with resistance (blood vessel diameter), and long term help would be needed at the kidney level
What is the vasomotor tone?
It is a constant output of NE to arterioles
Where is the vasomotor center located?
The medulla
Where does vasomotor input come from?
Baroreceptors, chemoreceptors, and higher brain centers
Where are baroreceptors found?
The carotid sinuses and aortic arch
What does increased MAP lead to?
dilation of arterioles, venodilation, and inhibition of the symp ns
