17 Blood Vessels Flashcards
What is anastomosis?
The union of two blood vessels e.g. vertebral arteries fusing into basilar
What is the inner space of a blood vessel called?
the lumen
What are the three layers that made up the walls of blood vessels?
Tunica Intima
Tunica Media
Tunica Externa
What type of cells line form the tunica intima?
simple squamous endothelium
Where does vasoconstriction and vasodilation occur?
tunica media
What is the tunica media made of?
circularly arranged smooth muscle fibers
What type of fibers make up the tunica externa?
collagen and elastic fibers
What is the thickest layer in arteries?
tunica media
What is the thickest layer in veins?
tunica externa
What internal structures distinguish the lumen of vein from arteries?
intralumenal valves
What layers make up capillaries?
only tunica intima
What is the order of vessels blood flows through from heart?
heart > elastic artery > muscular artery > arteriole> capillary > venule > medium vein > large vein > heart
Which arteries are elastic arteries?
Aorta, brachiocephalic artery, common carotid, subclavian artery, common illiac arteries
What is special about the external fibrous layers of elastic arteries?
High elastin content dampens pressure changes from cardiac output
What characteristic behavior is observed in muscular arteries?
Thick tunica media actively contracting and relaxing to control lumen size and blood flow to tissues.
What factors control arteriole diameter?
local tissue factors
sympathetic nervous system.
What is the functional unit of caridovascular system? Why?
Capillaries. That is where nutrient, waste, and gas exchange occurs
What are the three types of capillaries?
Continuous (most common)
Fenestrated
Sinusoid
Where are fedestrated capillaries found?
Small intestine, most endocrine glands, kidneys
Where are sinusoid capillaries found?
Bone Marrow, spleen, liver
What controls the flow rate in capillaries?
precapillary sphincter
what is the direct connection between arterioles and venules called?
thoroughfare channel.
What is the primary location for diapedesis?
Venules
What pumps the blood in veins back to the heart?
Skeletal muscle contractions
What adult structure does the ductus arteriosus become?
ductus arteriosum
What is it called when the ductus arteriosus stays open after birth?
Patent Ductus Arteriosis
What is average blood pressure?
120/80
What is the blood pressure threshold for hypertension?
140/90
What percentage of deaths in the US can be partially attributed to atherosclerosis?
50%
Which arteries are most affected by atherosclerosis?
aorta and coronary arteries
What is atheroma?
Fatty plaque narrowing arterial lumen and thickening tunica intima
What is an abdominal aortic aneurysm and what are the risk factors?
Localized dilation of blood vessels, most often arteries. Often caused by athererosclerosis.
What is a thrombus?
a blood clot that forms in brain blood vessel
What is an embolus?
a blood clot formed in another blood vessel
What is a cerebrovascular accident?
A stroke.