Lesson 6 - Cardiovascular Dynamics and Physiolgy Flashcards
blood flows through the body in what kind of system?
a closed circulation system
what can impact the rate of blood flow? (2)
the physical properties of blood and of blood vessels
what other factors can influence blood flow? (2)
- blood pressure
- peripheral resistance
blood flow equation
deltaQ: amount of blood flowing through the area
P: blood pressure; force of blood against vessels
n: ‘thickness’ of blood
r: radius of vessel
l: length of vessel blood travels through
the heart can only pump blood that is held…
within its ventricles
diastole (2)
relaxation, heart chamber is able to fill with blood
end diastolic volume (EDV)
blood volume in ventricles before contraction
systole (2)
contraction, chamber pushes blood out
end systolic volume (ESV)
blood volume remaining after ventricular
stroke volume (SV)
amount of blood pumped per contraction
stroke volume equation
EDV-ESV
end-diastolic - end-systolic
cardiac output
amount of blood pumped by each ventricle
cardiac output equation
SV x heart rate (in bpm)
as you increase the radius of blood vessels, the peripheral resistance of blood flow _____
decreases
radius of blood flow is _____ proportional to peripheral resistance
exponentially
how does the body regulate blood vessel radius?
through contraction or relaxation of the smooth muscles in those vessels, controlled by the ANS
what is an advantage of slowing blood flow at capillaries?
to increase the time for nutrient/waste exchange
as blood viscosity increases, blood flow _____
decreases
the relationship between viscosity and blow flow is…
negative exponential
ways in which blood viscosity increases (2)
- number of blood cells increases like polycythemia
- amount of plasma decreases like through dehydration
as vessel length increases, blood flow _____
decreases
vessel length is _____ proportional to blood flow
inversely/negative exponential (?)
why does resistance increase with vessel length?
blood flowing through a long vessel with interact with the walls for a greater period of time, producing more friction
it is much easier for the body to control blood flow through what? Over what?
radius of blood vessels vs. trying to destroy and shorten blood vessels
as pressure increases, flow _____
increases
pressure is _____ proportional to blood flow
directly (linear relationship)
how can the cardiovascular system increase blood flow?
causing an increase in blood pressure through increasing the force of cardiac muscle contraction
what can high blood pressure to do vessels?
can damage them if they are not used to higher pressures, possibly bursting
as the right radius increases, peripheral resistance _____ and blood flow _____
decreases, increases- right radius is the aorta (?)
how does pressure remain the same even as the radius changes?
the increase in blood pressure by the heart when vessels dilate balances out the decrease in resistance
as stroke volume increases, pump rate _____
decreases
why does pump rate decrease with increased stroke volume?
the preload (amount of blood filling the ventricles) increases, it takes more time to push out that volume
increases in stroke volume are balanced by…
decreases in heart rate to keep cardiac output the same
why might an athlete’s heart rate be lower than normal?
their heart has a higher stroke volume and does not require as high of a heart rate to push the same amount of blood, they also have a lower afterload
what does an aortic valve stenosis do to the heart?
increases afterload, aka the resistance to blood flow out of the heart
what does the heart have to do to overcome a higher afterload?
the heart has to contract harder to create more pressure to force blood out
someone with an aortic valve stenosis will have thicker _____
myocardium, the heart has to pump harder
what is the mechanism the heart uses to compensate for an aortic valve stenosis?(2)
increase contractility by sympathetic stimulation, or norepinephrine/epinephrine release
the heart has _____ and _____
automaticity and rhythmicity
what does it mean for the heart to have automaticity and rhythmicity?
it can spontaneously depolarize in a regular and continuous manner to cause heart contractions
contractions of the heart can be influenced by what two things?
parasympathetic or vagal stimulation, and sympathetic stimulation
what can over stimulation of the parasympathetic system cause? how can it rescue itself?
- the heart can stop beating !!
- but it can ‘restart’ by means of vagal escape
vagal escape
caused by sympathetic reflexed or rhythm initiation by Purkinje fibers
since the heart can be influenced by both the sympathetic and parasympathetic systems…(3)…can affect heart rate/contractions.
- direct stimulation of the systems can change heart rate
- chemicals that affect the systems also affect the heart
- ions can also affect heart contractions
what ions can impact heart contraction? (3)
Ca2+, K+, and Na+
What data is being shown by this graph?
vessel radius on pump activity
- right radius represents the aorta
What is being displayed in this data?
blood vessel radius on pump activity (?)
what does this graph show?
flow rate dependent on pressure
what does this data show?
flow rate dependent on pressure
what does this graph show?
flow rate vs. length of vessels
what does this data show?
blood vessel length on blood flow rate
what does this graph show?
flow rate vs. blood viscosity
what does this data show?
blood flow vs. blood viscosity
what does this graph show?
flow rate vs. vessels radius
what does this graph show?
blood vessel radius vs. blood flow
