test 3: lecture 4 Flashcards
Tony’s heart rate is 90 BPM, his left ventricular end diastolic volume is 135 mL, and his end systolic volume is 35. What is his cardiac output? (Remember to show units of measurement!)
CO= SV x HR
SV= EDV-ESV
135-35= 100x90
9000ml/min
9 L/min
C. decreased capacity for passive stretch
heart A is less compliant- less stretchy
Based on your understanding of the cardiac cycle, can you postulate what a phonogram from a patient with an aortic stenosis might sound like?
AS would be aortic valve not closing all the way
AS can be heard during systole
lub swish dub
Based on your understanding of the cardiac cycle, can you postulate what a phonogram from a patient with an PDA might sound like?
continuous swish
happens all the time, systole and diastolic
pda= patent ductus arterious
what kind of stenosis occurs during systole
pulmonic and aortic and PDA
what kind of stenosis occurs during diastole
tricuspid and mitral and PDA
Which of the following could increase cardiac output (in healthy heart)?
A.Increasing afterload
B.Decreasing end-diastolic volume
C.Increasing preload
D.Decreasing stroke volume
c increasing preload
(more ventricle stretching= more blood in ventricles= more tension in the wall produced by the end-diastolic pressure)
____ the pressure in the static circulation ( 7 mmHg)
mean circulatory filling pressures
___ represents a potential energy that propels blood through the circulation
blood pressure
why the 2nd increase?
blood going through right side of the heart
change in pressure/ resistance
flow
what is at each dot
MAP
mean arterial pressure
pressure gradient across the systemic circuit
ΔP ≈ MAP
•pressure in aorta minus pressure in the venae cavae just before emptying into right the atrium
PAP
pulomonary arterial pressure (15mmHg)
ΔP ≈ PAP
•Pressure gradient across pulmonary circuit
pressure in pulmonary arteries minus pressure in pulmonary veins
knowing flow between the pulmonary and systemic circuit is equal, and pressure in systemic is greater than pulmonary. What can you conclude about the resistance in each circuit?
systemic has more resistance
•The pressure gradient in the ___circuit is much greater than the pressure gradient in the ___circuit. Even so flow is equal
systemic
pulmonary
poiseuille’s equation
flow is basically
Resistance = 1 / (44)
flow= ΔP/R
____ = combined resistance of all blood vessels within the systemic circuit
Total peripheral resistance (TPR)
flow= ΔP /R
cardiac output (flow)= MAP/TRP
- Flow = cardiac output (CO)
- ΔP = mean arterial pressure (MAP)
- R = total peripheral resistance (TPR)
MAP/TPR
Cardiac output (flow) = mean arterial pressure/ total peripheral resistance
Flow= ΔP/R
- Flow = cardiac output (CO)
- ΔP = mean arterial pressure (MAP)
- R = total peripheral resistance (TPR)
Large arteries have high elastin, leading them to:
- Expand as blood enters during systole
- Recoil during diastole
(dicrotic notch= increase in aortic pressure after the valve closes after systole)
what is the consequence of having elastin in large arteries?
elastin allows for expansion and recoil during diastole
this leads to more steady flow of blood through the arteries through diastole and systole
mean arterial pressure
MAP = (SP + (2 x DP))/3
spend more time in diastole then systole
pulse pressure
systolic - diastolic
waveforms change based where in the body you are
why do pulse pressure waves in different areas look different
each bump is where blood spilts at a fork, small amount of blood will go backwards at the fork- causes turbulence
explain why pulse pressure looks different for same area
top from younger person with elastic walls
bottom from older person with stiff walls, the pressure created from hitting a stiff wall and then moving backward is bigger then the pressure from hitting a elastic wall,
therefore the backwards pressure of the stiff wall merges with the pressure of the earlier wall, creating one big pressure wave backwards
what happens to pulse pressure when you increase stroke volume
increase pulse pressure and increase mean pressure
increase the pressure during systolic
what happens to pulse pressure if you decrease the HR?
diastolic pressure decreases, MAP decreases
what happens to pulse pressure if you increase stroke volume and decrease HR?
mean pulse pressure stays the same
increase the systolic pressure and decrease the diastolic pressure
3 ways to change pulse pressure
increased SV, decreased HR, decreased arterial compliance
if you decrease arterial compliance what happens to pulse pressure?
mean stays the same but the systolic increases and the diastolic decreases
what happens to pulse pressure if you increased the total peripheral resistance
mean would go up
systolic and diastolic pressures would increase
what happens to pulse pressure if you decrease arterial compliance, increased total peripheral resistance
MAP would increase and both the diastolic and the systolic pressures would increase
what happens to pulse pressure during a PDA or aortic regurgitation?
MAP goes down, diastolic down, systolic up
pulse pressure
different between the systolic and diastolic pressures in a vessel
basically the amplitude= systolic- diastolic
laminar blood flow
blood in the center of the tube flows faster then blood closest to the edges because the edges have higher resistance
predicts flow patterns in different flow conditions
reynold’s number
korotkoff sounds
hear the turbulence of blood through the cuff
when taking blood pressure, increase pressure to no sound, the slowly decrease pressure until you hear a sound (these are korotkoff sounds- 5 types)
1) Crisp, snapping (systolic pressure)
2) Quieter swooshing (auscultatory gap)
3) Louder, crisp tapping
4) Muted thumping (first diastolic sound)
5) Silence (second diastolic sound)
2 ways to measure CO
CO= HR x SV
or
CO= MAP/TPR
____ provide resistance to blood flow
arterioles
- More than 60% of Total Peripheral Resistance (TPR) is from arterioles
- Resistance is regulated through action on smooth muscle
branching in capillaries does what to the speed of blood
decreases the flow
allows time for gas exchange
movement of material across capillary walls has two purposes
1.Exchange materials between blood and cells
- Diffusion
- Transcytosis
- Mediated transport (brain)
2.Maintain normal distribution of extracellular fluid
- Filtration = movement out of capillary into interstitial space
- Absorption = movement into capillary from interstitial space
Exchange materials between blood and cells in the capillaries occur through
- Diffusion
- Transcytosis
- Mediated transport (brain)
maintenance of normal distribution of ECF in the capillaries occurs by __
- Filtration = movement out of capillary into interstitial space
- Absorption = movement into capillary from interstitial space
is there more filtration or absorption closer to arterioles in capillaries?
more filtration toward the arterioles
what direction if the net hydrostatic pressure in capillaries?
net pushing filtrate out
hydrostatic pressure gradient: force due to blood pressure (Pcap)
___: osmotic force of proteins
•Oncotic pressure ∏CAP
net oncotic pressure is into the capillaries (trying to balance the amount of proteins on either side
what direction is net oncotic pressure?
into the capillaries
pressure from protein gradient
which is stronger hydrostatic forces vs osmotic pressure in capillaries
hydrostatic is stronger
there is a net filtration out of the capillaries
force of hydrostatic pressure out of capillary is greater then force of osmotic pressure from oncotic pressure(protein pressure in)
starling forces
measure flow across a membrane
(filtration vs absorption)
Q = K[(Pc-Pi) - σ (πc-πi)]
Q = flow
K= filtration coefficient
Pc= capillary hydrostatic pressure
Pi = interstitial hydrostatic pressure
σ = reflection coefficient
πc= capillary oncotic pressure
πi= interstitial oncotic pressure
Positive Q = Filtration Negative Q = Absorption
positive Q with the starling formula results in ___
filtration (movement out of the capillary)
Q = K[(Pc-Pi) - σ (πc-πi)]
negative Q for the starling forces results in ___
absorption
(net movement into the capillary)
Q = K[(Pc-Pi) - σ (πc-πi)]
Filtration coefficient
used in starling forces to determine direction of flow
K= filtration coefficient
Q = K[(Pc- Pi) - σ(πc- πi)]
- hydraulic permeability of capillary wall
- Net volume filtered in 1 min by 100gm of tissue for a 1mm Hg change
- Varies from tissue to tissue (depending on capillary density in each tissue type)
Reflection coefficient
σ= reflection coefficient
Starling Forces: determine flow= Q = K[(Pc- Pi) - σ(πc- πi)]
- the relative impediment to the passage of a substance through the capillary membrane
- Between 0 (water) and 1 (albumin)
if reflection coefficient is 0 what does that mean
very easy for substance to move through capillary membrane
water has a σ (reflection coefficient) of 0
while albumin has a σ (reflection coefficient) of 1
used in the starling force equation: Q = K[(Pc- Pi) - σ(πc- πi)]
if reflection coefficient is 1 what does that mean
very hard for substance to move through capillary membrane
water has a σ (reflection coefficient) of 0
while albumin has a σ (reflection coefficient) of 1
used in the starling force equation: Q = K[(Pc- Pi) - σ(πc- πi)]
decrease in intracapillary hydrostatic pressure would cause ___
net flow back into capillary instead of out of capillaries
can be caused during circulatory shock
if you increase ___ hydrostatic pressure, edema will happen
intracapillary hydrostatic pressure
net out even bigger then normal
can be caused by : •Renal retention of salt and water (kidney failure)•High venous blood pressure (standing too long; heart failure)
___ plasma proteins will cause edema
decreasing
this will decrease oncotic pressure back into the capillaries, resulting in an even bigger net pressure out of the capillaries
can be caused by •Renal retention of salt and water (kidney failure)•High venous blood pressure (standing too long; heart failure)•
___ capillary permeability will cause edema
increasing
it allows protein to leave, which will decrease the oncotic pressure back into the capillaries, net result would be higher pressure out of capillaries
can be caused by •Renal retention of salt and water (kidney failure)•High venous blood pressure (standing too long; heart failure)
doing what to lymph return will cause edema
blocking
lymph can’t enter the systemic system again causing back flow into tissues
The body can adjust flow through the following areas in an effort to regulate capillary filtration
•Arterioles
•Metarterioles
- Directly connect arterioles to venules
- Function as shunts to bypass capillaries
•Precapillary sphincters
•Contract and relax in response to local factors only
___ is considered the volume reservoir
veins
very complaint - expands with little change in pressure
2 mechanisms of venous return
•Skeletal muscle pump
- One-way valves in peripheral veins
- Skeletal muscle contractions/relaxation pumps blood towards heart
•Respiratory pump
•Inspiration creates negative pressure and subsequent blood flow towards thoracic cavity
how does skeletal muscle pump work in venous return
- One-way valves in peripheral veins
- Skeletal muscle contractions/relaxation pumps blood towards heart
how does respiratory pump in venous return
Inspiration creates negative pressure and subsequent blood flow towards thoracic cavity
An increase in venomotor tone leads to
- Increased central venous pressure
- Decreased venous compliance
- Increased venous return
(venomotor tone comes from smooth muscle tension in the veins)
increasing or decreasing venous compliance will increase venous return
decreasing
descreasing = less compliant= less stretchy
think steel tube- if you run into a steel wall you are more likely to bounce back faster and harder then a stretchy tube, this means when venous return hits against decreased compliant valves of the veins it will get to heart faster
If cardiac output is 5.3L/min, and mean arterial blood pressure is 80 mmHg, what is the total peripheral resistance? (Remember to show units of measurement!)
CO= MAP/TPR
5.3 L/min= 80 mmHg/TPR
TPR= 15 mmHg (L/min)
