exam 4- circulatory 1 Flashcards
describe the fluid compartment breakdown for a typical 70 kg adult male
total body water volume = 60% body weight
fluid compartments divided b/w:
. intracellular fluid (25 L total)- intracellular divided into somatic cell volume (23 L) & RBC volume (2 L)
. and extracellular fluid (15 L total) - extracellular divided into interstitial fluid (12 l) & fluid that’s in circulatory system (plasma- 3 L)
blood made up of both plasma and RBC volume - so 5 L (so blood made of both extracellular & intracellular fluid –> b/c of that, blood is a non-utonian fluid- meaning it doesn’t act like water)
blood is made of both ___ and ___ fluid, so it is called a ___ fluid
extracellular (plasma)
intracellular (RBC)
non-utonian
fluid compartment breakdown of 55 kg adult woman
proportions are roughly the same, actual volumes differ
- 55% of body weight
intracellular (22 L)
extracellular (11 L)
examples for circulatory system almost always ___ circulation - starts in the ___
systemic
left ventricle- goes to all tissues of body and then goes back to heart
describe circulatory system path starting in left ventricle
start with left ventricle –> pumps all blood to aorta (2.5 cm diameter, 5 cm long) –> aorta gives off main systemic arteries (each of these have small diameters, but there are more of them) –> each major artery gives off web of smaller arteries called arterioles (very numerous, microscopic diameters) –> each arteriole gives off capillary bed (individual capillary diameter ~ 5 microns) –> delivers blood to tissues and picks it up when it leaves –> capillaries come together to give venules –> form the major veins –> forms superior and inferior vena cava
total cross-sectional area of capillaries is ___ and blood flow velocity to the capillaries is ___
huge
slow
describe relationship b/w cross-sectional area and fluid flow
individual arteries total cross-sectional area is small b/c there are only a couple of them (each one is huge though) –> as you get closer to capillaries, number of vessels is so much larger (each one is small though), so total area is large
fluid flow through a pipe is inversely proportional to total cross-sectional area (as get closer to capillaries, blood flow through those vessels slows down and reaches slowest velocity through capillaries)
capillaries themselves are very ___, so residence time of blood in capillaries is very ___ (___), but this is enough for all the ____ to go to completion
short
small (less than a second)
exchange processes (like diffusion)
describe fluid dynamics in terms of fluid flow vs. resistance
fluid flow through a pipe is inversely proportional to the resistance through the pipe (less resistance –> fluid flows faster)
- resistance depends on radius of the pipe (inversely proportional to the radius of the 4th power)
–> fluid flows out of larger pipe 16 times faster than smaller pipe (flows out of vein faster than capillary)
circulatory system is a closed system, so it is basically one closed circuit (volume that goes thru certain component has to go thru it in same amt of time that it goes thru other components) –> what goes into aorta has to come out of aorta, what goes into capillaries has to come out of capillaries at the same time (flow is constant, but velocity changes in certain components of circulatory system)
flow = area x velocity
artery –> capillary bed (small cross-sectional area thru small pipe and large cross-sectional area thru larger pipe)
. volume is same, so flow has to be same (always constant)- velocity in smaller pipe has to compensate in order for flow to be the same
is velocity of blood flow faster in arteries or capillaries?
arteries
which component of the circulatory system has the slowest velocity of blood flow?
capillaries
what is blood pressure a function of?
describe diff BPs in relation to this
(the heart generates pressure to pump blood thru circulatory system)
blood pressure is a function of proximity to the pump (closer blood is to the heart, higher the blood pressure will be)
100 mmHg near heart and large arteries –> in arterioles and capillaries, huge decrease in BP as blood moves farther from heart (drop in BP across capillaries has a functional significance in delivering nutrients and oxygen to tissues and picking up waste)
–> when blood gets to venules and veins, at about 10 mmHg
what is Pcap?
what is the other one called
Pcap (hydrostatic pressure, just another term for BP) = pressure of blood pushing outward on the capillary wall as its pushed thru the capillary
Plasma colloid osmotic pressure- tends to pull (inward) substances, especially water, back into the capillary thru the capillary wall
describe differences in Pcap and plasma colloid osmotic pressure in arterial vs. venous ends
at arterial end, pcap (outward pressure) is 32 mmHg & plasma colloid (inward pressure) is 25 mmHg
—> net pressure is 7 mmHg - so pushes water outward through capillary wall into interstitial space
(as blood travels thru capillary, gets farther from heart, so BP gets lower)
at venous end, Pcap is 15 mmHg pushing out (but b/c you lose water as you go, osmotic pressure increases- 25 mmHg)
—> net pressure is 10 mmHg inward, pulls water back into capillary before it leaves – rudimentary circulation of fluid thru the interstitial fluid, not static (helps exchange of substances)
WATER PUSHED OUT AT ARTERIAL END & PULLED BACK IN AT VENOUS END
protein concentrations in capillary vs. interstitial fluid
in capillary, high conc of protein
in interstitial fluid- low conc of protein
–> unequal distribution of a large, impermeable negatively charged substance across membrane
- protein attracts NaCl across membrane, so higher conc of salt in plasma than interstitial fluid (this pulls water back in)
- more water is filtered than is reabsorbed at venous end of capillary (excess of water accumulates in interstitial space) –> water gets collected in lymphatic system
