Slide Set 1 Flashcards
Free water clearance is governed by
ADH
Flexible vessels have a _____ pulse pressure, while stiff vessels have a ______ pressure.
narrower; wider
Formula for compliance
C = ΔP/ ΔV or ΔP/CO
Compliance is
how stretchy our vessels are
Elastance is
how resistant our vessels are to stretch; rigidity
Formula for elastance
1/compliance
Formula for MAP
DBP + 1/3(SBP-DBP)
Pulmonary artery pressure
25/8
Mean pulmonary arterial pressure
16
Left atrial pressure range
2-5 mmHg
Left venticular pressure range
2-120 mmHg
Right atrial pressure range
0-4 mmHg; assume 0 mmHg
Right ventircular pressure range
0-25 mmHg
List, in order from greatest to least, the cross sectional areas of the vessels
Capillaries: 2500 cm
Venules: 250 cm
Veins: 80 cm
Arterioles: 40 cm
Arteries: 20 cm
Vena Cava: 8.5 cm
Aorta: 2.5 cm
What metabolic byproducts are likely to be let go at the level of the capillary
Hydrogen ions, carbon dioxide, and adenosine
Normal Pcap: what is it and what does it favor
30 at arterial end; 10 at venular end - Physical fluid pressure or BP in the capillary; favors filtration at arterial end and reabsorption at the venular end
Normal Pisf: what is it and what does it favor
-3 mmHg; hydrostatic/hydraulic/physical pressure of interstitial fluid; favors filtration
Normal Πcap: what is it and what does it favor
28 mmHg; capillary colloid osmotic pressure or oncotic pressure; favors reabsorption
Normal Πisf: what is it and what does it favor
8 mmHg; intersitial fluid colloid osmotic pressure; favors filtration
For each _____ drop below the heart, BP drops __ mmHg?
13.6 mm or 1.36 cm; 1
Pouiselle’s Law equation
Flow = Π(r^4)ΔP / 8n
Formula for distensibility
ΔP/(ΔV x original volume)
Define distensibility
Estimate of how expandable something is
Systemic veins are __x distensible than systemic arteries
8
Equation for Reynolds number; what does it indicate
Re = vdp/n; a result > 2000 indicates turbulent blood flow
When does pulse pressure widen?
When vessels are less compliant
What is CN IX?
Glossopharyngeal nerve
What does NTS stand for?
Nucleus tractus solitarius
What is CN X?
The vagus nerve
When the baroreceptors sense a high blood pressure they
increase their firing rate; stimulate the PNS and inhibit the SNS
What is happening during phase I of the cardiac cycle?
FILLING
Phase I is divided into thirds:
AV valves open
1st third is a rapid filling when the pressure of the atria exceeds that of the ventricle
2nd third adds about 10 mL of volume
3rd third sees a small increase in ventricular pressure due to atrial kick
What is happening during phase II of the cardiac cycle?
ISOVOLUMETRIC CONTRACTION
AV valves close
All valves are closed
Start of systole
Rapid increase in intraventricular pressure
What is happening during phase III of the cardiac cycle?
EJECTION
Aortic valve opens
Divided into thirds
1st third is a period of rapid ejection; 70% of SV ejected
Last 2/3s sees a slower rate of ejection and aortic pressure starting to exceed that of the ventricle
What is happening during phase IV of the cardiac cycle?
ISOVOLUMETRIC RELAXATION
Aortic valve closed
All valves closed
Rapid decrease in intraventricular pressure
Slight increase in aortic pressure before sharp decrease
V wave starts d/t building up of fluid in atria
A wave signals
atrial kick; caused by the kickback of blood into the vena cava at end of diastole
V wave signals? When does it occur?
result of volume building up in the atria; occurs at the end of systole or phase IV
C wave indicates? When does it occur?
pressure from the tricuspid valve bowing back during ventricular contraction
Phase II
The P wave preceeds
the A wave or atrial kick
QRS occurs before
a spike in intraventricular pressure
Normal ESV
50 mL
Normal EDV
120 mL
Normal SV
70 mL
What value of intraventricular pressure does the aortic valve close at?
100 mmHg
A right shift in the venous return (VR) curve indicates
an increase in venous tone or volume
A left shift in the venous return (VR) curve indicates
a decrease in venous tone or volume
The majority of filling pressure is dictated by
venous tone
Venous return formula
VR = Psf-RAP / RVR
Without increases in circulating catecholamines, the heart can increase it’s CO to?
13 L/min
A left shift in the CO curve indicates
strong sympathetic stimulation or hypereffective heart
A right shift in the CO curve indicates
parasympathetic stimulation or a hypoeffective heart
Another phrase for Psf (systemic filling pressure)
Mean circulatory filling pressure –> includes pulmonary circuit
Increases in SVR can cause increases in
RVR (resistance to venous return)
Increases in RVR cause the slope to
Decrease
Dec
