Exam 1 Flashcards
Label the following.
See picture
What is Free H2O clearance, what is it regulated by & what does a high number mean?
How much pure H2) is removed from the blood. Regulated by ADH & high # means getting rid of a lot of water.
What is the systemic pulse pressure?
100mmHg
What is the CVP in a healthy person & where is it measured?
It should be 0 & is measured outside the RA.
Where are low & high compliance found?
Low compliance is on arterial side & veins have a high compliance.
What is the meaning of pulse pressure?
It relates to how stiff vessels are. Low PP means more flexible. High PP means stiffer (arteries).
Where is turbulent flow found & what is another function of it?
In the Aorta & acts as a volume reservoir.
What is another word for compliance?
Elasticity. Higher elasticity means higher compliance= more stretch.
What does elastance mean?
How rigid something is. It is the inverse of compliance. High elastance = low compliance.
What kind of compliance is found in the pulmonary system?
High compliance due to low resistance.
What do vasopressors not innervate?
Capillaries & cranial sinuses.
Which has a higher velocity, aorta or vena cavae?
Aorta
MAP Formula
Diastolic + 1/3 (Systolic – Diastolic)
What tells arterioles to relax & increase flow?
Waste products
What are the colloid pressures of Albumin, Globulins, & Fibrinogen?
21.8, 6, & 0.2 (mmHg)
What is normal lymphatic flow & what is max?
2L/day & max is 40L/day
Where does the lymphatic system drain into & what controls the flow?
The subclavian vein. Controlled by skeletal muscles.
Do the lungs have a lymphatic system?
Yes, but it does not work as well as the systemic one.
Where would one encounter negative venous pressures?
In the cranial sinuses
BP at Thigh has how much extra pressure?
40mmHg
BP at the femoral artery bifurcation would be?
142/102 mmHg; + 22mmHg
If a BP is measured on a healthy person’s wrist & it reads 150/110 mmHg, how much arm distance is below the heart?
40.8cm (1.36cm for each 1 mmHg increase.
What is the formula for Vascular compliance?
Compliance= Delta volume / Delta pressure
High volume and low pressure result in ____ compliance?
High
What are normal pulmonary pressure:
Systolic
Diastolic
Mean
25/8 mmHg (16 mmHg)
What is the pulmonary Delta P?
14 mmHg (MPAP= 16 mmHg & LA pressure = 2 mmHg)
What is the normal pressure range for the RA?
0-4 mmHg
What is the normal pressure range for the RV?
0-25 mmHg
What are the normal pressure ranges for LA & LV?
LA= 2-5 mmHg & LV= 2-120 mmHg
When CO is 5L/min, CVP is?
What is CO when CVP is 4?
CVP = 2
CO= 2.5
What is the formula for vessel velocity?
- Velocity= Flow (5L/min) x cross sectional area of vessel
- Cross section: Radius squared x 3.14
What are the beginning pressure, end pressure & Delta P of capillaries?
Beginning= 30 mmHg, end= 10mmHg,
Delta P= 20mmH
What is the capillary colloid pressure?
28mmHg
What is the interstitial fluid pressure?
-3mmHg
What is the average pressure inside a capillary?
17mmHg
What are the πp & g/dL of Albumin, Globulins & fibrinogen?
- Albumin: 21.8 mm Hg & 4.5 g/dL
- Globulins: 6 mm Hg & 2.5 g/dL
- Fibrinogen: 0.2 mm Hg & 0.3 g/dL
Sympathetic vasoconstriction releases _____?
Norepinephrine
What is normal intrathoracic pressure?
-4mmHg or -5cm H2O
What structural pressure is not affected by gravity?
Jugular veins
Veins are ___ times more/less _____ than arteries.
8, more & distensible
What is the formula for vascular distensibility?
Vd= Increase in Volume / (Increase in Pressure x Original volume)
What is the formula for Delta P?
Delta P= F x R (Flow times Resistance)
What is the formula for Flow?
- F= π △Pr4 / 8 η l
- [ (π times Delta P times radius to 4th power) / 8 times viscosity times length) ]
Conductance is proportional to?
Diameter to the 4th power
Small volume to large volume means?
High distensibility
What is the formula for predicting turbulent flow?
Re= [ (v x d x p) / η ]. (velocity x diameter x density / viscosity)
____ pressure & ____ velocity= low compliance.
High & low
Vascular Resistance unit PRU is also equivalent to what?
mmHg/mL/sec
Vascular resistance unit CGS is also equivalent to which two units?
mmHg/L/min = Centimeter Gram Second unit = Dynes x sec / cm⁵
How to convert CGS units to PRU?
1333 x PRU (mmHg/ml/sec)
What kind of sensors are carotid baroreceptors?
Stretch sensors
Aortic baroreceptors are controlled by the ____ thru the ____?
Medulla NTS (nucleus tractus solitarus & Vagus nerve
The carotid & aortic baroreceptors function at the same pressures?
False the aortic receptors function at a BP 20-30mmHg higher.
The carotid baroreceptors receive their signal from the ___, which then sends it thru the ___ & then thru the___?
Hering’s nerve & Glossopharyngeal nerve & Medulla (NTS) vasomotor center.
If someone was to have no baroreceptors, it would result in?
Denervated Neurons lead to increase in _____ of BP.
Higher BP fluctuation.
Increase in variability
If both carotid arteries were to be clamped for short period of time, what happens to the arterial pressure?
What mechanism limits the BP rise when carotids sense low BP
Is will increase 50-60mmHg
Aortic Baroreceptors will sense high BP and limit pressure increase
What is normal ESV?
50cc
What all happens in phase 1?
Filling, ESV=50cc, AV valves open, high atrial pressure, low intraventricular pressure
What is the normal EDV?
120cc
What all happens in phase 2?
Isovolumetric contraction, AV valves close, all 4 valves are closed at the beginning
What all happens in phase 3?
Ejection, peak pressures at 120mmHg, aortic valve closes @100mmHg
What all happens in phase 4?
Isometric relaxation, all 4 valves are closed, ESV= 50cc
What happens during the 1st part of Phase 3?
- 70% (49cc) of SV is ejected,
- LV pressure higher than aortic pressure,
What happens during the 2nd part of Phase 3?
- 30% (21cc) of SV is ejected
- at end aortic pressure > LV pressure
What is the 1st heart sound?
A-V valves (bicuspid and tricuspid) closing
Low pitch
What is the 2nd heart sound?
Semilunar Valves Close (Aortic & Pulmonic)
High Pitch
Why does the 1st heart sound vibrate more than the 2nd?
The aortic valve is meatier & doesn’t vibrate as much
Compare atrial kick in a healthy vs sick heart?
- In a healthy heart it contribute 5-10% &
- In a sick heart it contributes 20-25%
Normal Afterload for LV
80mmHg
A RA pressure of -4 mmHg will results in?
6L venous return
A RA pressure of 7 results in what?
0 CO & VR (Venous return)
System Psf
Another acronym for Psf?
+7 mm Hg
Ppv = Psf
Psf (systemic filling pressure) depends on 2 things
Tone & volume of the system
A Psf of 14 mmHg results in how much venous return?
12L/min
A Psf of 3.5 mmHg results in how much venous return?
4L/min
Effects on CO Curve:
Changing Psf
Changing Resistance
Psf changes size and position of curve.
Resistance changes shape (slope) of graph
Increases Psf:
Effect on RVR
Decreases RVR
Normal Arterial Volume
700cc
What does Pcv stand for?
Thoracic pressure
Maximum CO for Normal Sympathetic Activation
13L/min
Maximum CO for Max Sympathetic Stimulation
25L/min
A left shift of the cardiac output curve results in what?
Increased CO & contractility
What are causes of a right shift of the cardiac output curve? (2)
Parasympathetic stimulation, bad heart
Direct Atrial Stretch Reflex
How is stretch sensed?
MOA
body responds to increased stretch in right atrium by 10-15% increase in HR & SV
Sensor/Mechanism: Already built into the heart
MOA: increase permeability to Na and Ca
Describe Bainbridge Reflex
How is stretch sensed?
Result?
Stretch in Atria sensed by Vagus Nerve transmits to brainstem’s cardioinhibitor.
Brainstem increases SNS activity
Inc HR & SV by 50-60%
What is a normal cardiac index & what is it for an 80y old?
Normal is 3.5 & 80y old is 2.4
Arterial Specific Vasodilator
Hydralazine
What is TPR
Another name for it?
Total peripheral resistance & SVR
Spinal Anesthesia effect on Psf, VR, CO?
Minimal effect on Psf, VR, and CO.
Slightly decreases
What are causes for increased CO & decreased TPR? (6)
AV shunts, Anemia,
Beriberi, Hyperthyroidism,
Pulmonary disease, Paget’s disease
What are causes for decreased CO & increased TPR? (2)
Remove both arms and legs
Hypothyroidism
Hypothyroidism effect on CO and SVR?
Increased SVR
Decreased CO
What is Beriberi?
-involved in cofactor for what?
S/s (3)
- Vitamin B-1 (thiamine) deficiency (a co-factor for ATP production)
- S/S: High CO, lactic acidosis, right heart failure
Increased O2 consumption & metabolism leads to what?
Increased CO
Explain SVR relationship to VR
- Increasing SVR –> increased resistance to venous return –> decreased venous return (L/min).
- Decreasing SVR –> decreased RVR –> increased venous return (L/min)
Halving & doubling RVR results in how much venous return?
Halving= 12L/min & Doubling= 4L/min
A right shift in the Cardiac Output/ Thoracic Pressure curve is caused by (2)
What is needed to compensate?
- PEEP, tamponade &
- Increasing BP to push blood into chest
Arterial Specific Vasodilator effects:
SVR
RVR
Reduces SVR and RVR
Mixed vasodilator effects:
Psf
RVR
CO
RA pressure?
Psf decreases (venodilation)
RVR decreases (arteriodilation)
CO Slightly decreases
RA moderately decreases
Reduce Compliance or add volume
Effect on Psf and VR
stiff walls –> inc Psf –> inc VR
Constriction effect on Psf and RVR
Increase Psf and RVR
Venular specific vasodilator
Effects on CVP, Psf, VR, CO
Drug Class Example
drop in CVP –> reduce Psf –> reduce VR –> reduce CO
NO Donor
Short-term/acute: constriction of the veins mediated via (2)
- circulating catecholamines
- neural reflex
Phenylephrine Important Effect
Increase Psf & SVR
Long term compensations of cardiac injury is (3)
fluid retention → volume expansion –> Psf increase
Administering 2u of blood effect on
Psf
Vessel size
RVR
Psf inc
Increased volume widens vessel walls
Which decreases RVR
sky high sympathetic tone makes you more prone to ? (2)
Electrical arrhythmias
Myocardial Infarction
Volatile & Spinal Anesthetics considerations for SNS?
What is the safest and why?
Volatile - high doses inhibit the Autonomic NS.
Spinal Anesthetics drifts up the cord.
Epidural is safest because outside the dural sac.
AV Fistula effect on Psf and RVR
AV Fistula - creates easier flow so
NO Psf change
RVR decreases
Label the following
See picture
What does the picture describe?
Increased Preload
Increased Preload results in?
EDV/SV/EF
- Increased EDV & SV.
- Slight EF increase.
Decreased preload will result in?
EDV/SV/EF
- Decreased EDV & SV.
- Slight EF decrease
Increased Afterload will result in?
ESV/SV/EF/ Aortic Pressure
- Increased aortic pressure.
- SV & EF decrease.
- ESV increases
Decreased Afterload will result in?
ESV/SV/EF
- Decreased aortic pressure.
- SV & EF increase.
- ESV decreases.
Increased contractility will result in?
ESV/SV/EF
- SV & EF increase.
- ESV decreases.