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bios 255 Exam 2 Questions and Answers 100% Pass
How many layers do blood vessels have? - ANSWER ✔✔-three
what are the three layers of blood vessels? - ANSWER ✔✔-tunica intima, tunica media, tunica externa
What is the tunica media? - ANSWER ✔✔-Smooth muscle and elastic fiber layer, regulated by
sympathetic nervous system. usually the largest layer
what is the tunica interna - ANSWER ✔✔-the inner lining of a blood vessel's wall composed of simple
squamous epithelium
what is the tunica externa - ANSWER ✔✔-Outermost, collagen and elastic fibers.
what are the elastic arteries - ANSWER ✔✔-Contain more elastic fiber than smooth muscle fibers; absorb
energy and stretch. largest arteries by diameter
what are muscular arteries - ANSWER ✔✔-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 - ANSWER ✔✔-smallest arteries
attached to capillary beds
used to control blood flow through the system capillary
chemoreceptor for o2
what are capillaries - ANSWER ✔✔-Capillaries are the exchange vessels. They are microscopic and have
only one wall—tunica intima—allowing substances to pass through quickly.
Created by Grace Amelia © 2025, All Rights Reserved.
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found in system capillaries
what are the three types of capillaries - ANSWER ✔✔-continuous, fenestrated, sinusoidal
What are fenestrated capillaries? - ANSWER ✔✔-Endothelium that contain "large"-diameter pores found
in places like the kidneys
What are sinusoidal capillaries? - ANSWER ✔✔-Highly modified, leaky, fenestrated capillaries with a
large diameter to allow large molecules (protiens and blood cells) to pass tissues. found in the liver
What are continuous capillaries? - ANSWER ✔✔-only small molecules can fit
overlapping endothelial
diffusion/bulk flow endocytosis
found in systemic capillaries
what are veins - ANSWER ✔✔-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 - ANSWER ✔✔-
vasoconstriction
valves
skeletal muscle pump
respiratory pump
cardiac suction
what are venules - ANSWER ✔✔-smallest veins attached to the capillary bed
an example of a medium vein - ANSWER ✔✔-jugular vein
Created by Grace Amelia © 2025, All Rights Reserved.
bios 255 Exam 2 Questions and Answers 100% Pass
How many layers do blood vessels have? - ANSWER ✔✔-three
what are the three layers of blood vessels? - ANSWER ✔✔-tunica intima, tunica media, tunica externa
What is the tunica media? - ANSWER ✔✔-Smooth muscle and elastic fiber layer, regulated by
sympathetic nervous system. usually the largest layer
what is the tunica interna - ANSWER ✔✔-the inner lining of a blood vessel's wall composed of simple
squamous epithelium
what is the tunica externa - ANSWER ✔✔-Outermost, collagen and elastic fibers.
what are the elastic arteries - ANSWER ✔✔-Contain more elastic fiber than smooth muscle fibers; absorb
energy and stretch. largest arteries by diameter
what are muscular arteries - ANSWER ✔✔-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 - ANSWER ✔✔-smallest arteries
attached to capillary beds
used to control blood flow through the system capillary
chemoreceptor for o2
what are capillaries - ANSWER ✔✔-Capillaries are the exchange vessels. They are microscopic and have
only one wall—tunica intima—allowing substances to pass through quickly.
Created by Grace Amelia © 2025, All Rights Reserved.
, 2|Page
found in system capillaries
what are the three types of capillaries - ANSWER ✔✔-continuous, fenestrated, sinusoidal
What are fenestrated capillaries? - ANSWER ✔✔-Endothelium that contain "large"-diameter pores found
in places like the kidneys
What are sinusoidal capillaries? - ANSWER ✔✔-Highly modified, leaky, fenestrated capillaries with a
large diameter to allow large molecules (protiens and blood cells) to pass tissues. found in the liver
What are continuous capillaries? - ANSWER ✔✔-only small molecules can fit
overlapping endothelial
diffusion/bulk flow endocytosis
found in systemic capillaries
what are veins - ANSWER ✔✔-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 - ANSWER ✔✔-
vasoconstriction
valves
skeletal muscle pump
respiratory pump
cardiac suction
what are venules - ANSWER ✔✔-smallest veins attached to the capillary bed
an example of a medium vein - ANSWER ✔✔-jugular vein
Created by Grace Amelia © 2025, All Rights Reserved.
