Exam1Lec2BiochemicanicalPropertiesofBloodVessels Flashcards
The blood vessel wall comproses of three main layers, what are they?
Tunica intima, tunica media, tunica adventitia. Elastic membranes are found in their interfaces
Thickness and composition of each layer vary according to what?
Vessel type (artery or vein) and diameter
Large arteries have a ____ media layer and ____ amount of elastin.
thick, high
Small arteries have a ____ amount of elastin and have ____ smooth muscle cells
lower, more
Veins have a ____ media layer and a ____ amount of elastin.
thin, low
Explain the pressure change in the left heart during the cardiac cycle
slide 5
explain
What is diastolic blood pressure?
lowest arterial pressure measured during a cardiac cycle
What is sytolic blood pressure?
highest arterial pressure during a cardiac cycle
What is pulse blood pressure?
Difference between systolic pressure and diastolic pressue (Ps-Pd)
if all factors are equal, the magnitude of PB reflects the volume of blood ejected form the LV in a single beat
What is mean blood pressure? Also what is the equation?
Average pressure during a complete cardiac cycle. Pa=Pd +0.33 (Ps -Pd)
know eq
What is mean blood pressure? Also what is the equation?
Average pressure during a complete cardiac cycle. Pa=Pd +0.33 (Ps -Pd)
know eq
Mean Bp is ____ throughout aorta and large arteries
similar
Mean BP ____ successively from aorta to vena cava
falls
____ BP is pulsatile but pulsation ____ in smaller vessels
Aortic, decreases
What is laminar flow?
Produces little vibration of arterial wall and no sounds
What is turbulent flow?
When an artery is partially constricted, blood flow becomes turbulent causing the artery to vibrate and produce sounds.
What are korotkoff sounds?
Tapping sounds associated with the turbulent flow
The auscultation method to measure BP is based on ____.
korotkoff sounds
The oscillometry
method to measure BP is based on ____.
arterial wall vibration
In the oscillometry method, when does turbulent blood flow occur?
When cuff pressure is greater than the diastolic and less then systolic pressure.
Using the auscultatory technique for measuring arterial blood pressure, how do you record systolic pressure?
You record the first sound you hear and this is where cuff pressure is equal to systolic pressure.
Using the auscultatory technique for measuring arterial blood pressure, how do you record diastolic pressure?
You record the last sound you hear and this is where cuff pressure is equal to diastolic pressure.
What is stroke volume?
Volume of blood pumped out from the left ventricle per beat.
What is Cardiac output (CO)?
The volume of blood being pumped out by the heart by the left or right ventricle per unit time,
CO=SV x HR
effect of stroke volume on arterial blood pressure
If stroke volume increases, what happens to
Q
Systolic BP
PP
Diastolic BP
Mean BP
Q incr
Systolic BP incr
PP incr
Diastolic BP incr
Mean BP incr
everything incr
effect of stroke volume on arterial blood pressure
If stroke volume decreases what happens to
Q
Systolic BP
PP
Diastolic BP
Mean BP
Q decr
Systolic BP decr
PP decr
Diastolic BP decr
Mean BP decr
everything decr
effect of heart rate on arterial blood pressure
If heart rate increases what happens to
Systolic BP
PP
Diastolic BP
Mean BP
Systolic BP incr
PP remains the same (no change in sv)
Diastolic BP incr
Mean BP incr
higher the hr, the higher the BP b/c there is less time for blood to flow from aorta to vascular tissues so they accumulate more blood in actual arteries
effect of heart rate on arterial blood pressure
If heart rate decreases what happens to
Systolic BP
PP
Diastolic BP
Mean BP
Systolic BP decr
PP remains the same (no change in sv)
Diastolic BP decr
Mean BP decr
there is more time to get blood flow from aorta to periph tissues
effect of TPR on arterial blood pressure
If TPR increases what happens to
Systolic BP
PP
Diastolic BP
Mean BP
Systolic BP incr
PP remains the same
Diastolic BP incr
Mean BP incr
more resistnace=heart works harder to move blood from aorta to peripheral arteries
effect of TPR on arterial blood pressure
If TPR decreases what happens to
Systolic BP
PP
Diastolic BP
Mean BP
Systolic BP decr
PP remains the same
Diastolic BP decr
Mean BP decr
Resistance is determined by what 3 things?
viscosity, vessel length, vessel radius,
length and viscosity are generally considered constant
How does an incr of radius affect resistance?
REDUCES resistance. The change in diameter alters resistance to the 4th power of the change in diamter
vessel resistance is very sensitive to diameter and blood flow
Aorta and large arteries have the lowest cross-sectional area meaning they have the
____ radius
____ resistance
____ blood pressure
lowest radius
highest resistance
highest blood pressure
From the arteries to arterioles, the cross sectional area (total radius) is gradually increased meaning that we see
____ radius
____ resistance
____ blood pressure
increased radius
decreased resistance
decreased BP
lower resistance-=lower BP=lower velocity=higher bf volume
vascular radius change
What is vascular tone?
Degree of constriction experienced by a blood vessel relative to its maximally dilated state.
how constricted a vessel is based on extrinisic and intrinsic factors that constrict tissue
Vasculaor tone is determined by what?
balance of competing vasoconstrictor and vasodilator influences (extrinsic and intrinsic factors)
How do Extrinsic factors regulate arterial blood pressure?
They come from outside the tisse and they altering systemic vascular resistance
ex: neural and humoral factors that cause vasoconstriction
How do intrinsic factors regulate arterial blood pressure?
These come from inside tisssue and are important for local blood flow regulation within an organ
ex: myogenic factors causing vasocontriction and tissue metabolites causing vasodilation
What is vascular stenosis?
abnormal narrowing of an artery, partially obstucting flow
lower vessel diameter, INCR VASCULAR RESISTANCE
most comonly accuring in large distributing arteries such as coronary, iliac femoral, etc.
The narrowing of an artery commonly results ffrom chronic disease processes such as?
Artherosclerosis
Explain “critical stenoisis” and give an ex
critical narrowing of an artery that results in a significant reduction in maximal flow capacity in a distal vascular bed
Ex: narrowing of iliac artery decr flow to piriformis muscle
What is vessel compliance?
The ability of a vessel to distend and increase volume with increasing transmural pressure (inside minus outside pressure)
What is the equation for arterial compliance ?
C=change in V/ change in P
If you have a high change in pressure, but a low change in volume do you have a lower or higher compliace?
Lower compliance
use graph if need visual
The volume that stretches the walls is called ____ and the rest is called ____.
stressed volume, unstressed volume
Ca (arterial compliance) is highest when?
Within normal physiological pressure range. It responds very well to change in pressure. You can also tell based on this picture, the slope of this curve within this range is high.
What is the equation for arterial elastance?
Ea=change in Pressure/ Change in volume
P and V is flipped when comparing to eq for compliance
When COMPARING Arteries to veins ARTERIES have
Lower or higher elastnace?
Lower or higher compliance?
Higher elastance
Lower compliance
ALSO HAS MORE SMOOTH MUSCLE CELLS COMPARED TO VEINS
When COMPARING Arteries to veins VEINS have
Lower or higher elastnace?
Lower or higher compliance?
Lower elastance
Higher compliance
less smooth muscled too, this is impt bc veins cna expand very quickly and easily which is good for blood storage.
Explain the windkissel effect in simple terms
Blood flow from heart to elastic arteries. Elastic arterfies can expand and act as pressure reservoirs. This allows for continous blood flow
Since the rate of blood entering the elastic arteries exceeds that leaving them to peripheral tissue, there is a net storage of blood in the arteries during ____ , which discharges during ____ to keep the blood flow continue.
systole, diastole
Elastic arteries Act as a Pressure Reservoir
The aorta and large arteries act as a “pressure reservoir”
(windkissel vessels), allowing what three things
- Continous blood flow to peripheral vessels
- Reduce workload on heart (b/c we recoil it pushes remainder of blood to capillaries)
- Reduce blood pressure fluctation
basically the abilioty to expand and recoil is needed to continue to push blood in body and regulate pressure
Explain artherosclerosis in terms of what happens with the arteries
The arterteries are stiff so they cannot expand or contract very well (basically no diameter changes) so we higher blood pressure occuring. This happens to a lot of older ppl
no dampening or windkiksself effect
As we age we see
____ compliance
____ stiffening
____ systolic BP
____ pulse pressure
lower
higher
higher
higher
With arterial stiffness we see
____ collagen
____ elastin
higher
lower
remember that elastin is the most important for expansion ability
side 25: The elastic tissue enables a blood vessel to expand and contract passively with changes in pressure.
What are 4 physiologcal properties of veins
High compliance
Low resistance
Blood reservoir system ( has 60-70% of total blood volume)
Venous valves have 1-way flow to heart
What are 5 ways veins can return blood to the heart?
- Pressure gradient
- Skeletal muscle pump with venous valves
- Respiratory pump
- Regulated sympathetic vasocostriction
- Carduac suction effect.
Explain how veins can push the blood back to the heart with pressure gradient
LV/Aorta has a HIGH pressure of around 120 and the pressure gradient is pushing blood back towards the heart we see LOW pressure of 0 at the right atrium.
think passive diffusion
Explain how veins can push the blood back to the heart with skeletal muscle pump (with venous valves)
This system is the major mechanism promoting venous return during normal locomotory activity
limbs have ine way valve flow away from limb towards heart.
Veins become compressed and relaxed as muscle compress and relax. See picture.
Explain how veins can push the blood back to the heart with respiratory pump.
WITH INHALATION we see
diaphragm ____
Blood pressure in abdominal cavity ____
Blood moves ____
thoracic cavity ____
pressure in pleural cavity ____
Incr blood flow into ____
diaphragm contracts
blood pressure in abdominal cavity incr
blood moves superiorly
thoracic cavity expands
pressure in pleural cavity decr
incr blood flow into thoracic veins
pulls blood from smaller veins in abdominal cavity into IVC and R atrium
Explain how veins can push the blood back to the heart with respiratory pump.
WITH EXHALATION we see
diaphragm ____
Blood pressure in abdominal cavity ____
thoracic cavity ____
pressure in pleural cavity ____
Incr bf into ____
diaphragm expands
Blood pressure in abdominal cavity **decr **
thoracic cavity incr
pressure in pleural cavity incr
Incr bf into heart (right atrium) and abdominal veins
pushes blood into R atrium
Explain how veins can push the blood back to the heart with regulated sympathetic vasoconstruction
With increased sympathetic stimulation you get vasoconstriction, incr venous pressure, incr venous return, incr EDV (end diastolic volume; the amt of blood about to be pumped out)
fight or flight
Explain how veins can push the blood back to the heart with the cardiac suction effect
pulling down on atria, incr total atrial volume (atrial cavity is bigger), lower atrial pressure driving blood into atria.
