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Name the blood path sequence from arteries to vena cava.
ateries, arterioles, metarterioles, capillaries, venules, veins, vena cava
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What are arterioles? structure and function
small arterial branches, made of endothelium and 1 layer of smooth muscle fiber, that deliver blood to capillaries. FYI as arterioles approach capillaries their walls become thinner
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What are metarterioles?
Microscopic branches of arterioles that connect to capillaries
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What are the smallest blood vessels?
Capillaries
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What type of cells make up capillaries?
simple squamos epithelium
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How many capillaries can arise from one arteriole?
Dozens
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What blood vessels is an extension of the endothelium of the larger vessels?
Capillaries
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Where is the only place the exchange of gases can occur in the cardiovascular system?
Capillaries
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Where are small capillary openings found?
Skin and all muscle types
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Where are the slightly larger openings of the capillary found?
kidneys, small intestine, and those associated with the endocrine glands
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Where are the largest openings of the capillaries found?
Liver, spleen, and red bone marrow
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Which capillary opening has sinusoids and incomplete or absent basement membranes?
the largest
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What regulates capillary blood flow?
precapillary sphincters
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What is exchanged between capillary blood and tissue fluid?
Gases, nutrients, and metabloic by products
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What is the most important means of transport?
Diffusion
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What is diffusion?
Molecules moving from high to low concentration
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What generally reamins in the blood and why?
plasma proteins, they are to big to pass through the pores
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Where will diffusion occur along the capillary?
Along the entire length
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What are lipid soluble substances?
oxygen, carbom dioxide, and fatty acids
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What are lipid insoluble substances?
Water, sodium, and chloride ions
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What type of transport involves hydrostatic pressure?
filtration
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Where does filtration occur ?
at the arteriole end where the B/P is highest( B/P decreases as it moves from arteriole to venule)
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What transport mechanism is used for the plasma proteins?
osmosis
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Where does osmosis take place?
throughout the capillary, but mostly at the venule end of a capillary where reabsorption predominates
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What are venules?
small veins that collect blood from capillaries and deliver it to larger veins
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What are veins?
thin walled blood vessels that carry blood to the heart with low pressure
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Which vein is the only vein to carry oxygenated blood?
pulmonary veins
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Where can lumens with a greater diameter be found?
in venous walls
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What is the difference between the tunica media of arteries and veins?
tunica media of veins is thinner and has less ealstic fibers
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What is the difference between the tunica externa of arteries and veins?
tunica externa is more prominent in veins
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Where else besides the heart can valves be found?
veins
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Define B/P.
the force exerted by blood against the inside of blood vessels
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What causes arterial pressure?
the action of the heart venrricles contracting and putting pressure on the arteries
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What is systolic pressures?
highest point of BP in the arteries as the ventricles contract
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What is diastolic pressure?
lower pressure on the arterial walls as the heart relaxes
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What are normal adult BP values?
Systolic= 110-140 mm Hg
Diastolic=60-90 mm Hg
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What is the definition of pulse?
the rhytmic expansion and recoil of an arterial wall due to ventricular contraction
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What does pulse rate correspond to?
heart rate, vibrations per min.
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What are normal pulse rates?
60-100 BPM
70-80 BPM = average
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Who would normally have a faster pulse?
A baby girl.(females are faster, younger age=faster pulse)
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What is bradycardia?
heartbeat below 60 BPM
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What is tachycardia?
Heartbeat above 100 BPM
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Where are the principle sites for taking a pulse?
- radial-thumb side inner wrist
- brachial- antecubital little finger side
- temporal
- carotid
- femoral-middle of groin
- popliteal
- dorsalis pedis
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What is peripheral resistance?
resisteance the vessels offer to the flow of blood. BP must be greater than this force
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How is peripheral resistance maintained?
By vasoconstriction(Arterioles contract) and vasodilation(arterioles dilate) controlled by the vasomotor center of the medulla
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What effect does vasoconstriction have on BP?
Increases
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What effect does vasodilation have on BP?
Decreases
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What is stroke volume?
the volume of blood discharged from each ventricular contraction
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What influences arterial BP?
- Cardiac output
- Blood Volume
- Peripheral resistance
- Viscosity
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BP=
Cardiac output(CO)*PR(peripheral resistance)
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What does venous blood flow depend on?
Skeletal muscle contraction, respiratory movements, venoconstriction
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Blood entering the hepatic portal is
oxygen poor but nutrient rich
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What ions influence heart action?
potassium and calcium
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What is hyperkalemia and what effect does it have on the heart?
Alteration of the polarized state of ions and causes a decrease in the heart rate, may result in cardiac arrest
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