Blood Vessels Flashcards
Arteries Definiton
take blood AWAY from the heart TO other tissues
Arteries
- transport blood high in oxygen (exception: pulmonary arteries)
- they have a relatively thick, springy wall
- blood pressure higher in arteries than in veins
Veins Definition
take blood back TO the heart
Veins
- transport blood low in oxygen and highin carbon dioxide (exception: pulmonary veins)
- compared to arteries, their walls are much thinner and collapsible
- lumen generally much larger than arteries
- blood pressure is lower in veins
Capillaries Definition
connecting arteries and veins are tiny vessels
Pathway of Blood
heart -> elastic arteries -> muscular arteries -> arterioles -> capillaries -> venules -> veins -> heart
Blood Vesscle Structure Components
Tunica Externa
Tunica Media
Tunica Intima
Tunica Externa
outermost layer
- areolar connective tissue
- largest layer in veins
Tunica Media
middle layer
- circularly arranged smooth muscle fibers
- largest layer in arteries
- sympathetic innervation typically causes vasoconstriction
Tunica Intima
Innermost Layer
Endothelium (simple squamous epithelium) and areolar connective tissue
Arteries Components
Elastic Arteries
Muscular Arteries
Arterioles
Elastic Arteries
vessel wall contains large amounts of elastic protein fibers
Muscular Arteries
less elastic than elastic arteries, and
more smooth muscle in the tunica media
Arterioles
tunica media consists of 6 or fewer layers of smooth muscle
Capillaries
vessel diameter is only slightly larger than the diameter of an erythrocyte! *have JUST a Tunica Intima
*gas/nutrient exchange occurs here!!!