Bios 255 Exam 2
How many layers do blood vessels have? - ANS three
What are the three layers of blood vessels? - ANS tunica intima, tunica media, tunica externa
What is the tunica media? - ANS Smooth muscle and elastic fiber layer, regulated by
sympathetic nervous system. usually the largest layer
what is the tunica interna - ANS the inner lining of a blood vessel's wall composed of simple
squamous epithelium
what is the tunica externa - ANS Outermost, collagen and elastic fibers.
what are the elastic arteries - ANS Contain more elastic fiber than smooth muscle fibers;
absorb energy and stretch. largest arteries by diameter
what are muscular arteries - ANS Contain fewer elastic fibers and more muscle fibers; can
contract (vasoconstriction) and relax (vasodilation). aka distributing arteries (most named
arteries are in this category)
what are arterioles - ANS smallest arteries
attached to capillary beds
used to control blood flow through the system capillary
chemoreceptor for o2
what are capillaries - ANS Capillaries are the exchange vessels. They are microscopic and
have only one wall—tunica intima—allowing substances to pass through quickly.
found in system capillaries
what are the three types of capillaries - ANS continuous, fenestrated, sinusoidal
What are fenestrated capillaries? - ANS Endothelium that contain "large"-diameter pores found
in places like the kidneys
What are sinusoidal capillaries? - ANS Highly modified, leaky, fenestrated capillaries with a
large diameter to allow large molecules (proteins and blood cells) to pass tissues. found in the
liver
What are continuous capillaries? - ANS only small molecules can fit
, overlapping endothelial
diffusion/bulk flow endocytosis
found in systemic capillaries
what are veins - ANS carries blood from the capillaries back to the heart (02 poor)
contain valves
what do veins rely on to create pressure to assist in returning blood to the heart - ANS
vasoconstriction
valves
skeletal muscle pump
respiratory pump
cardiac suction
what are venules - ANS smallest veins attached to the capillary bed
an example of a medium vein - ANS jugular vein
what are large veins - ANS superior and inferior vena cava
Blood in the axillary artery goes to what vessel next? - ANS brachial artery
what is the equation for blood flow - ANS change in pressure/resistance
what is the equation for MAP - ANS (systolic pressure - diastolic pressure)/3 + diastolic
pressure
what three factors determine systemic vascular resistance - ANS blood vessel diameter
blood vessel length
blood viscosity
what happens when there is an increase in blood viscosity - ANS thicker blood which is harder
to move and requires an increase in blood pressure to maintain the original flow
what happens when there is an increase in blood vessel length - ANS increases resistance
increase in blood pressure to maintain original flow
what happens when the blood vessel diameter increases - ANS increases resistance
increase in pressure
what is cardiac output - ANS amount of blood pumped out of the left ventricle per minute
how to calculate cardiac output - ANS heart rate x stroke volume
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