As you move further from the heart, the pulse pressure changes how? Why? What is a good example of this?
- WIDENS (increased difference between systole & diastole)
- COMPLIANCE DECREASES as you move further from heart - Left $ right arm – right arm has lower diastolic and higher systolic pressure because it is further from the heart
How is the diastolic pressure of the Aorta as compared to the Left Ventricle?
HIGHER in Aorta (more compliant)
- thus velocity is converted to pressure - recoil of the aorta
Mean arterial pressure is determined ore by systolic than diastolic pressure. True or False?
FALSE
- diastolic pressure determines MEAN arterial pressure
Why is systolic pressure higher & diastolic pressure lower in the arteries as compared to aorta?
Arteries are less compliant
- compliance decreases as you go further from the heart
Where is there NO PULSE PRESSURE?
Capillaries & veins
As vessels get less compliant (stiffer), how is the pulse pressure affected?
INCREASES (widens)
What drives blood forward if systolic pressure is higher downstream?
MEAN ARTERIAL pressure declines (energy declining)
- so the pressure gradient is created again
What type of hypertension is common in younger people? Older people?
Younger - DIASTOLIC hypertension
Older - Systolic
Which ventricle generates 5 times higher pressure?
LEFT VENTRICLE
Due to the elasticity of the Aorta & after load of the arterial BP
- more energy
- ventricle hypertrophies slightly due to the pressure
The incisura/ or high frequency component, is dampened where?
FURTHER from heart
How are the following affected as you move further from the heart:
- Incisura
- Systolic Peak
- Diastolic Hump
- Dampens peak
- Systolic peak INCREASED
- LATE DIastolic hump
What are 3 causes for alterations in pressure profiles? What is the main reason?
- Reflection at branch points - flow hits branch pt. & they summate
= wave hits wall & peak is HIGHER - Vascular Tapering - forces fluid into a narrow opening, increasing pressure
- DECREASE IN ARTERIAL COMPLIANCE
= MAIN REASON!!
What is atherosclerosis?
ATHEROSCLOROSIS: hardening of the arteries, compliance of the vessels is decreasing
Which vessel has the highest amount of elasticity?
AORTA
Which vessels: arteries or veins, have strong connective tissue?
VEINS
What cells provide protective lining & release local transmitters like NO?
ENDOTHELIAL CELLS
- if damaged = inflammation to rest of arterial wall
- stents: put in to prevent further endothelial damage
What are all blood vessels & lymphatic vessels lined with?
ENDOTHELIAL CELLS
What are the 3 layers of both arteries and veins?
- Tunica Intima
- Tunica Media
- Tunica Adventitia
Which vessel, veins or arteries has the following:
- IEL
- EEL
- innervation
- vasa Vasorum
ARTERIES
Which vessels have well developed connective tissue in the tunica adventitia?
VEINS
- no IEL
- no EEL
What does vasa vasorum provide?
NUTRIENTS to the vessels (both veins & arteries)
Why can veins withstand high pressures? What can veins be used for?
- well-developed ADVENTITIA
- BYPASS graft (saphenous vein)
- due to large connective tissue
Which vessels have the following:
- Elastic Lamina
- MORE SMOOTH muscle
- LESS CONNECTIVE TISSUE
ARTERIES
Which layer has the highest compliance (elastic lamina, smooth muscle, collagen)?
ELASTIC LAMINA
How do the compliance characteristics of arteries tissues affect arterial pressure?
Compliance of arteries (low) so this causes an increase in arterial pressure
What is the change in compliance in low & high volume situations for arteries?
LOW volume = HIGH compliance
- high volume = stretching the collagen so compliance is LOW
What type of capillaries are found in the following:
- Muscle, connective tissue
- Liver, bone marrow, spleen
- Kidney, Intestine
Which have tight junctions? Diaphragm? Discontinuous endothelial cells w/ discontinuous basal laminae
- Continuous Capillary
- Discontinuous Capillary (allows large substances to pass)
- Fenestrated Capillary
- filters fluid, absorbs nutrients
Which have tight junctions? Diaphragm? Discontinuous endothelial cells w/ discontinuous basal laminae
- Continous Capillaries
- Fenestrated
- Discontinuous
- tight jcts = COntinuous
- Fenestrated = Diaphragm
- Discontinuous endothelial & basal laminae
What allows for greater control of vessel diameter & blood flow?
HIGHER
Wall thickness/lumen diameter ratio!
What vessels have highest wall thickness/lumen diameter ratio & GREATEST control? Least?
Pre- capillary sphincters (2nd is arterioles)
- VEINS
thin wall, large diameter (small ratio)
= regulate VOLUME not flow or pressure
Higher wall thickness/lumen diameter ratio directly corresponds with what?
LOW WALL TENSIOn
- allows vascular smooth muscle to easily constrict the vessel
(arteriole - 1.3 & capillaries - 2)
Why is an increase in pulse pressure bad? This is a result of what specific value that relies on change in volume & pressure?
increases the AFTERLOAD
which increases the oxygen consumption of the heart
- COMPLIANCE (low compliance = increased after load & widens the pulse pressure)
- increase systolic
- decrease diastolic
What occurs when blood is ejected into the arterial system under HIGH COMPLIANCE?
moves the wall(during systole),
-by moving the wall you reduce the pressure because the movement is KINETIC energy
- so Potential energy is reduced so systole is LOW
- then after the aortic valve closes: the aorta recoils & the kinetic component (velocity) is put back into PRESSURE (potential component) & moves the diastolic pressure a little higher**
When is the diastolic pressure higher: under high compliance or low compliance? When is it low?
HIGH compliance
- low compliance = stiff –> PE not converted to KE during systole (wall doesn’t move; stiff)
and when diastole occurs there is no recoil so pressure DROPS OUT
- lower since KE not converted back to PE
What is an independent risk factor for heart failure? Why?
LOW COMPLIANCE
- due to increased oxygen consumption
As radius or volume increase, how does pressure change? What is a clinical application of this?
INCREASES
-at low volume, low pressure change
- at higher volumes, LARGE pressure change because the LOAD is no longer on elastin & smooth muscle, it is on collagen
Clinical: blood volume expansion causes HYPERTENSION - given diuretics/ace inhibitors to decrease blood volume & after load
What are the Windkessel/Hydraulic Filter properties of the aorta?
blood ejected into the aorta - when it is initially ejected it DISTENDS as a result of the compliance characteristics
–it recoils after valve closes & acts as a secondary PUMP
(no recoilL no increase in diastolic pressure & thus higher pulse pressure)
ex: loss of dicrotic notch due to no recoil = RIGID ARTERY
How does aortic compliance change with age?WHY?
LESS compliance
- more collagen, less elastin
- given increase in volume elicits a LARGER increase in pressure
= wider pulse pressure MORE CARDIAC WORK
The following is due to what?: 1. CHF Contributes to: 2. Systolic Hypertension 3.Cardiac Hypertrophy 4. Aortic DIlation 5. Low exercise tolerance
INCREASED pulse pressure
Arteries are ____ vessels & Veins are ______ vessels.
- Resistance vessels (due to low compliance)
- Capacitance Vessels
- high compliance in physiologic pressure range
Why do veins exhibit a high compliance in physiological pressure rage?
Due to their geometry
- ability to dilate & collapse
ex: when sitting, they are collapsed
What is the PRESSURE PULSE (not pulse pressure)? The larger this is, means the more what changes?
Pulse felt in the wrist (radial) due to an energy wave distending the artery
- movement of the artery is transferred into wall
LARGER PRESSURE PULSE = more the wall distends
Propagation of pressure pulse wave depends on what characteristic of the vessel wall? What kind of vessels have greater propagation?
COMPLIANCE
- stiffer = greater propagation since the wall distends less
The arterial pressure pulse is directly related to changes in what?
ARTERIAL PRESSURE PROFILE
- ex: close to aorta –> the pressure pulse is small because it is very COMPLIANT & elastic
Which pulse would be stronger: pedal or radial pressure pulse?
PEDIAL
How is pressure pulse related to atrial fibrillation? How would this be noticeable when taking someones pulse with AFib?
- since amount of blood ejected with every contraction is IRREGULAR (and not constant) & amount of energy with each beat is different
PRESSURE PULSE IS NOT CONSTANT!
- so if you feel a radial pulse it would be faster, slower, and changing