Cardiovascular System (Blood Vessels) Flashcards
is the only part of a vessel that is in contact with blood
Tunica intima
Tunica intima is made of ________ called ______ which is continuous with the endocardium of the heart
simple squamous epithelium called endothelium
controls the diameter of the vessel’s lumen
tunica media
involved in the maintenance of normal blood pressure
tunica media
Tunica media is made of ______ and ____
smooth muscle and elastic connective tissue
When the tunica media relaxes, its lumen diameter is high which causes?
vasodilation and decreases the blood pressure
is important to prevent the rupture or bursting of the larger arteries that carry blood under high pressure
Tunica externa
carry blood from the heart to the capillaries
arteries
where the exchange of materials between the blood & tissues take place
capillaries
have higher pressures since they directly arise from the heart
arteries
the pressure generated by the pumping action of the heart
hydrostatic pressure
TRUE OR FALSE: the hydrostatic pressure increases as it gets farther from the heart
FALSE
arteries, as they branch out usually ____ or connect with one another to provide alternate routes for the flow of blood
anastomose
Flow of blood
collateral circulation
the artery which has the highest hydrostatic pressure
aorta
where all the large, medium & small arteries of the systemic circulation arise from
aorta
smallest, almost microscopic, arteries that branch off the small arteries into capillaries
arterioles
its smooth muscles control the amount of blood reaching the capillaries
arterioles
are thin-walled, microscopic vessels (5-10 μm wide) which connect the arterioles & venules (smallest veins)
capillaries
they surround almost every cell in the body, and are highly metabolic
capillaries are more numerous in _____
muscles, liver, kidneys, and nervous system
capillaries are fewer in the _____
tendons and ligaments
capillaries are absent in
covering and lining epithelia, cornea, and cartilage
capillaries are made up of
endothelium
their thin walls permit exchange of substances between blood & interstitial fluid
capillaries
TRUE OR FALSE: the rate of blood flow in
capillaries is fast to permit sufficient time for the exchange of substances
False
refers to the movement of substances between blood & interstitial fluid w/c occurs mostly via diffusion & filtration
capillary exchange
since the O2 level of blood is high, it diffuses from blood to tissue; since CO2 concentration in tissues is high, it moves from tissues to blood
diffusion
occurs in the arterial end of a capillary; the high hydrostatic pressure pushes plasma & dissolved nutrients (glucose, amino acids & vitamins) out of the capillaries & into interstitial fluid
filtration
follows filtration; occurs in the venous end of a capillary; since there is low hydrostatic pressure in this area, the high colloid osmotic pressure exerted by albumin in the blood pulls back most of the pushed fluid from the tissues into the capillaries
reabsorption
What capillary end has higher hydrostatic pressure?
arterial end
the rest of the excess interstitial fluid is absorbed by the
lymphatic system
What do the arterial end of the capillary pushes out to the interstitial fluid?
plasma and dissolved nutrients (glucose, amino acids, and vitamins)
What do the venous end of capillary pushes in?
interstitial fluid or tissue fluid
is swelling caused by too much fluid trapped in the body’s tissues.
edema
carry blood from capillaries back to the heart
veins
TRUE OR FALSE: Veins have thicker tunica media and externa than arteries.
FALSE
What do the tunica intima of veins contain?
valves
when the blood moves toward the heart, their valves will?
open
caused by increased blood pressure in the veins
varicose veins
they are blood reservoirs
veins
when the need for blood arises (e.g. hemorrhage, exercise), the tunica media of the veins ____ to increase venous return to the heart
constrict
small, almost microscopic, veins that carry blood away from the capillaries toward the heart
venules
the largest of all the veins w/c return blood back to the heart
venae cavae
smooth muscles in the tunica media constricts to promote
venous return
the veins _____prevents backflow of blood and promote venous return against gravity
valves
What are the three Mechanisms that promote venous return?
- Vasoconstriction and Venous Valves
- Skeletal muscle pump
- Respiratory Pump
contraction of the skeletal muscles surrounding the veins causes “milking” of the veins between these muscles which squeeze blood towards the heart
skeletal muscle pump