blood vessel structure and function lab quiz

arteries carry blood away from heart and divide into smaller vessels called

arterioles

what do arterioles branch into

capillaries

what happens at the capillary level

there is an exchange of nutrients, wastes, and gasses between blood and interstitial fluid

capillaries join together to form what?

venules

what do venules merge into?

veins that carry blood back to the heart

what happens in systemic circulation?

arteries carry oxygen rich blood to the body tissues and veins return oxygen poor blood back to the heart for pulmonary circulation

what happens in pulmonary circulation?

arteries carry oxygen poor blood from the right ventricle to the lungs where gas exchange occurs and veins return oxygen rich blood to the left atrium

how many layers do arterial walls have?

tunica intima, tunica media, and tunica externa (3)

what is the tunica externa made of and its function?

elastic and collagen fibers that provide support and protection

what is the tunica media made of and its function?

middle thickest layer and contains elastic fibers and smooth muscle fibers that encircle the diameter of the vessel and allows the vessel to be stretched and return to original shape

how is the tunica media controlled?

by the sympathetic nervous system regulating the diameter of the vessel by vasoconstriction or vasodilation through smooth muscle fibers

what is the tunica intima made of and its function?

contains endothelium (simple squamous) lines the lumen of blood vessels to form a barrier promoting blood flow, a basement membrane, and elastic tissue

what happens if there is damage to the endothelium?

causes platelets to stick to blood vessel walls and form plaques that narrow the linen and impede blood flow

what are elastic arteries?

large diameter arteries that have more elastic fibers in the tunica media than other arteries and they stretch under great pressure when blood is pumped into them during systole

what happens to elastic arteries during diastole?

elastic fibers recoil to continue blood flow

what are muscular arteries?

small than elastic arteries and contains more smooth muscle in their tunica media to distribute blood to different areas of the body through vasoconstriction and dilation

what do muscular arteries branch into?

arterioles and then capillaries branch from there

what are the characteristics of an arterioles?

tunica media containing mainly smooth muscles and few elastic fiber

what do arterioles control?

control blood flow into capillaries and play a large role in controlling blood pressure

blood flows from capillaries into venules that drain where?

into the veins

what 3 layers do the veins contain? and what is the thickest layer?

tunica intima, tunica media, and tunica externa (tunica externa being the thickest)

what does the arteries contain that the veins do not in their structure?

external elastic lamina and internal elastic lamina

muscular activity squeezes the veins and pushes blood toward the heart while venous valves do what?

prevents the backflow of blood in limbs

folds of the tunica intima with cusp like structures create what in the venous structure?

venous valves

what does a faulty or incompetent venous valve do?

allows back flow of blood which results in pooling of blood in the veins (varicose veins)

what vessel has the smallest diameter and thinnest walls?

capillaries

what is the structure of capillary walls?

endothelium and supported by a basement membrane and a very small lumen

fusion of plasma membranes is adjacent cells

tight junction

spaces between cells

intercellular clefts

pores in plasma membrane covered by diaphragm

fenestrations

which 2 substances are allowed to cross capillary walls with tight junctions between cells?

lipid soluble or membrane carriers (also intercellular clefts, fenestrations, and vesicles)

molecules can be transported across capillary walls by vesicles called

transcytosis

what is another word for blood pressure?

hydrostatic pressure

hydrostatic pressure at the arterial end of the capillaries causes what to happen?

plasma to be filtered across the capillary wall into the interstitial fluid

what does a filtered plasma contain and what is it then become?

nutrients, hormones, and other substances becomes interstitial fluid once it leaves the capillaries and enters the space around tissue cells

blood osmotic pressure draws what substance into the venous end of capillaries?

interstitial fluid

after interstitial fluid is brought into the venous ends of capillaries what does it bring into the blood?

fluid, metabolic waste, hormone, and other substances

what is blood pressure?

the pressure exerted by blood against blood vessel walls

where is blood pressure highest?

in the aorta and large elastic arteries until arteries branch and blood travels away from the heart which causes decrease in pressure

what vessel does blood pressure drop significantly in?

the arterioles and steadily decreases through capillaries, venules, and veins and then drops to 0 in the right atrium

what is the blood pressure gradient?

difference in blood pressure between 2 areas of circulatory system

blood pressure gradient between the aorta and right atrium causes blood to flow through…

systemic circulation

blood pressure gradient between pulmonary trunk and left atrium causes to flow through…

pulmonary circulation

within the arterioles, little to no fluctuations in blood pressure between what and what are observed in capillaries or venous vessels?

systole and diastole

blood pressure gradient between veins and right atrium is which makes it difficult for what to happen?

for venous blood flow to overcome the force of gravity causing blood to pool in large veins of the limbs

why is the bp cuff inflated to a pressure greater than the systolic pressure?

it puts pressure on the arteries, flattens it, and stops the blood flow in the artery

what happens after you inflate the bp cuff beyond normal systolic pressure?

pressure in the cuff is slowly released by opening a valve (where blood pressure is greater than the pressure in the cuff, the artery opens and blood flow returns)

where is the stethoscope placed to hear blood flow into bp?

over brachial artery

what does the examiner listen for?

turbulent flow of blood until returning to normal

what is the korotkoff sound?

noise heard during measurement of bp

why is blood pressure important?

ensures adequate blood flow to the body tissue

what happens if blood pressure is too low?

tissue perfusion may not be sufficient enough to provide cells with oxygen and nutrients (especially brain neurons and metabolic wastes)

what happens if blood pressure is too high?

can cause damage to capillaries and endothelial lining of blood vessels

what can eye exams detect?

early hypertension through damaged retinal vessels

during exercise what increases to provide adequate tissue perfusion (blood flow to tissue)

cardiac output

increase in stroke volume during exercise put more pressure on blood vessel walls which causes

arterial systolic blood pressure to increase

what is peripheral resistance?

resistance or friction blood experiences as it flows through vessels

what happens to blood pressure during aerobic exercise and why?

diastolic blood pressure stays the same or decreases slightly due to vasodilation bc widened blood vessels allow blood to flow easier

what happens to blood pressure during resistance training (weight lifting) and why?

diastolic pressure increases due to vasoconstriction (skeletal muscles contract strongly causing squeezing or compression on the arteries)

what does map stand for? and what does it tell us?

mean arterial blood pressure (in one heartbeat) tells us the average force pushing blood through arteries

why is map important

it tells us if there is enough tissue perfusion

when does MAP increase?

when cardiac output increases and when resistance to blood flow increases

how does vasodilation affect map

decreases resistance and lowers bp

how does vasoconstriction affect map

it increases resistance and increases bp