Exam 3- CV dynamics Flashcards
Flow rate of a liquid through a pipe is
directly proportional to the pressure gradient
indirectly proportional to the pipe’s resistance
select the three best choices that would DECREASE RESISTANCE to blood flow
increase radius
decrease length and blood viscosity
which has the greatest effect on blood flow
radius
blood flows in the opening of the blood vessel referred to as the _____
lumen
the driving force for blood flow is
pressure gradient
the body increases blood vessel radius through
smooth muscle rlaxation
after eating a heavy meal, while inactive one would expect
blood vessels to skeletal muscles to be constricted
blood vessels to digestive organs to be dilated
what is the source of the pressure gradient that drives fluid/blood flow in the body?
CO/ the heart pump
when you increased the flow tube radius the fluid flow rate
increased exponentially by a factor of 4
which do NOT contribute to viscosity of blood
CO2, O2, Na+ [ ]
the thickness or “stickiness” of a fluid is the ____
viscosity
increasing the viscosity
decreases flow rate
hypoalbuminemia is a reduction in serum albumin. The effect on blood viscosity would be to
decrease blood viscosity thus decrease resistance
with dehydration one would predict
increased viscosity and decreased flow rate
describe the components of blood that affect viscosity, and how changing the components change viscosity
The components of blood that affect viscosity are plasma proteins and formed elements. These include WBCs, RBCs, and platelets. Increasing any of these components will cause them to slide past one another more, increasing resistance and viscosity (decreasing flow rate). Decreasing any of these components will cause them to slide past eachother less, decreasing viscosity (increasing flow rate).
decrease blood flow
polycythemia vera
IV transfusion of RBCs
dehydration
increases blood flow
iron deficient anemia
liver disease
chronic gloeruloephritis
IV hydration with normal saline
What happens to vessel length then you lose weight?
decreases
increased flow tube length this lead to a
decreased flow rate
Which change occurs on a daily basis
diameter
The body might decrease vessel radius
decrease delivery of nutrients to an area that is less metabolically active
which correctly describes the relationship between blood vessel length, resistance and blood flow
blood vessel length is directly proportional to resistance and inversely proportional to blood flow
why does a 10% change in blood vessel radius affect blood flow more than a 10% change in blood vessel length?
When changing blood vessel radius by 10%, blood flow is affected by more than 10% because blood flow increases to the fourth power of the vessel radius.
why does weight change affect blood pressure
Weight directly affects the length of the vessels. The longer the vessel (heavier person) the more resistance/friction in the vessel, slowing th flow and increasing the pressure. The opposite will happen for a lighter person. Shorter vessel, less resistance, faster flow, decreased pressure
the driving force for blood flow is
pressure gradient, which increases with an increase in cardiac output
increased pressure or cardiac output from the heart will, in absence of other changes
increased blood flow
arteries closest to the heart are described as elastic arteries because they stretch in response to
pressure from ejection of blood during systole
What is laminar flow, and what effect does a smaller vessel radius have on laminar flow
Laminar flow is blood that flows freely in the middle of the vessel. In a smaller, vasoconstricted vessel there is more contact between the blood and the lumen decreasing laminar flow. This prevents or delays the rate of blood flow in the vasoconstricted vessel when compared to vasodilated vessels.
isolated increase in force of contraction in the heart would likely
increase BP
isolated increase in arterial radius would likely
increase BF to the area
Was the plot for change in pressure different than that for changes in radius/viscosity or tube length? If so what was different
he pressure plot had a linear trend in the positive direction demonstrating a directly proportional relationship. The radius/viscosity and tube length, the trend was in an exponential manner representing the indirect relationship
There is a more effective method for controlling blood flow throughout the body than changing the strength of contraction of the heart. What is it and why is it more effective?
The more effective method of controlling blood flow would be vasoconstriction and vasodilation. Changing the vessel diameter controls the flow of blood more effectively because it is a factor that is more easily changed from minute to minute.
hen the piston pushed blood out of the chamber the volume remaining in the chamber would be closest to the
ESV
layer of a blood vessel most affected by the ANS is
smooth muscle
ncreased contractility of the heart results in all but which of the following
increase ESV
the effect of increasing the R flow tube radius
increased flow rate
decreased resistance
increased pump rate
In a normal individual [a] percent of the blood contained within the heart is ejected during ventricular systole leaving [b] percent in the ventricle
60, 40
at rest the overlap length for maximum tension production in cardiac muscle is
less than optimum
factors that can decrease preload are
severe blood loss
tachycardia
dehydration
The cardiovascular system can adjust blood flow from either the heart or the peripheral vascular system.
What two changes can the heart make to adjust blood flow?
would this have a systemic effect (affect the whole body) or a local effect (just affect one part of the body)
change SV and HR
effect on systemic- BP and blood flow
the degree to which the ventricles are stretched by the end diastolic volume is the _____
preload
the pump rate was analogous to the heart rate, what happened to the rate when you increased the stroke volume?
the pump rate decreased to maintain cardiac output
why might an athlete’s resting Heart rate be lower than an untrained individual
the athlete’s heart has stronger contractions thus stronger stroke volume
compare optimal muscle length in cardiac muscle compared to that in skeletal muscle. What does this mean for cardiac function?
Optimal length for cardiac muscles is in a stretched length compared to skeletal muscle which has an optimal length at rest. The stretching of the myocardium allows for the sarcomeres to have optimal overlap of actin and myosin to produce the most efficient contraction. For cardiac function, this means that the more preload (prestretch) of the cardiac muscle, the stronger the contraction
Which had the greatest compensatory effect?
increasing pump pressure
Aortic valve stenosis would cause an
increased L ventricular afterload
in vivo the heart would compensate for a decrease in flow tube radius by
adjusting the force of contraction of the heart
In arteriosclerosis arteries lose their elasticity. One would expect
an increase in systolic BP, a decrease in diastolic BP thus a widening of the pulse pressure
in aortic valve regurgitation during diastole blood flows back into the L ventricle. This effect would
increase preload in the next cycle thus increasing pulse pressure
