CV 2 anatomy set two. handout page 7-15 Flashcards
______are similar to precapillary sphincters but are mostly found in the mesentery.
metarterioles
______can serve as a bypass channel between arterioles and venules by altering perfusion of the tissues such as closing precapillary sphincters and stopping perfusion to the mesentery while exercising.
metarterioles
in this type of vessel the tunica media is normally absent but may have 1-2 layers of smooth muscle cells.
venules
in this type of vessel the tunica media is normally absent but may have 1-2 layers of smooth muscle cells.
venules
venules are usually found along side_____
arterioles
the function of these vessels are to collect blood flow from the capillaries and they merge to form small veins
venules
short, thick walled vessels that directly connect arterioles and venules
arteriovenous anastomoses
arteriovenous anastomoses open and close in response to _______ stimulation not _________.
arteriovenous anastomoses open and close in response to sympathetic nervous stimulation not metabolic regulation.
arteriovenous anastomoses directly connect what?
arterioles and venules
found in areas where the amount of blood flow varies due to ambient temperature such as ears, hands, feet, face, nose, lips, shoulers, upper chest, nail beds, just beneath dermal capillaries
arteriovenous anastomoses
found in skin that is exposed but poorly insulated by subcutaneous fat
arteriovenous anastomoses
form small units called glomus bodies
arteriovenous anastomoses
the primary function of _____ is thermoregulation
arteriovenous anastomoses
what would happen to arteriovenous anastomoses related to SNS activity in response to cold
- cold
- increased SNS activity
- constrict
- less blood flow through arteriovenous anastomoses
- less heat loss through skin
opposite for hot
_____formed from the merging of venules
small veins
the tunica media of this vessel is thin 2-4 layers of smooth muscle
small veins
the function of ___is to drain blood out of organs into medium sized veins
small veins
the named veins of the arm elbow and below are considered ______viens.
cephalic, basilic, lesser saphenous
medium veins
the tunica media of medium veins is _____with ___layers of smooth muscle.
thin
2-4 layers
at intervals along only the ______sized vein/vessels the tunica media extends into the lumen as paired semilunar folds.
medium
valves do not appear in what veins
thorax or abdomen
the vein’s valves serve what function
prevent backflow and assist with propulsion of blood towards the heart
internal jugular, brachiocephalic, pulmonary, renal, hepatic portal, vena cava are all examples of what type of vein
large veins
the thickest section of the large veins would be the ______.
(superior and inferior vena cava)
tunica adventitia
describe the tunica media of the large veins
thin with a few layers of longitudinal smooth muscle that helps control distention of the vessel
the function of the large veins is?
collectively the veins(venules to large veins) contain most of the blood volume (⅔) when the body is at rest
the veins constrict to increase venous return to the heart
some arteries found in the GI tract and joints of the limbs join together with other arteries and form______.
arterial anastomoses
(serve as collateral circulation)
provide collateral circulation/more than one route for blood flow into a region of the body or organ when an artery is disrupted by accident, disease, or ligation
arterial anastomoses
venous anastomoses are often found where?
distal body regions
with the exception of erectile tissue there is almost no ______nerve supply to the blood vessels
parasympathetic
