Exam 3 Kirk Lecture Systemic Circulation Flashcards
Vessles are primarily composed of:
1.
2.
3.
4.
Vessels are primarily composed of:
elastin
collagen
smooth muscle
endothelial cells
________ is a change in pressure caused by a given change in volume
At low pressures, veins are _____ than arteries
Compliance: change in presssure by a given change in volume
For a given stroke volume into the aorta, the aortic pulse pressure is increased when compliance is reduced
At low pressures, veins are way way more compliant than arteries.
At low pressures, veins can collapse down (have high compliance)
Arteries have ____ compliance, therefore they are considered ____ vessels
Arteries have very low compliance, and they are considered resistance vessels
Comparing Arteries to Veins:
a) artery has _____, veins do not
b) artery has ____ smooth muscle than veins
c) artery has ____ connective tissue than veins
Arteries have elastic lamina (both internal and external), vein’s don’t
Arteries have more smooth muscle than veins
Arteries have less connective tissue
What kind of valves do veins have?
veins have one way valves (unidirectional)
Rate the following in terms of highest to lowest compliance:
smooth muscle
collagen
elastic lamina
Highest compliance to lowest:
elastic lamina > smooth muscle > collagen
Arteries exhibit a relatively constant ____ compliance. Therefore artieries are considered ______ vessels.
Veins exhibit a relatively ____ complaince due to changes in geometry. Therefore, veins can accomadate relatively large volumes of blood with little increase in pressure and are considered ____ vessels.
Arteries: low complaiance, resistance vessels
Veins: high compliance, capacitance vessels
At higher pressures, the compliance of veins is __
At high pressures, compliance of veins is low
veins are full at this stage, and you start to push on their smooth muscle, resulting in a decreased compliance compared to normal
This allows veins to be used as coronary bypass grafts
Label this diagram
What is it? Label 1, 2, 3, and 4
Large elastic artery:
- Endothelium
- Internal Elastic Laminae
- Tunica Media
- Tunica Adventia (this is where small blood vessels called vasa vasocorum are located)
For a given stroke volume into the aorta, the aortic pulse pressure is _____ when compliance decreases
Aortic pulse pressure will increase
when compliance decreases
remember, think about what happens with age, more collagen builds up in the aorta, decreased compliance creates an increase/widening in pulse pressure
What are the three types of capillaries?
Three types of capillaries:
Continous capillary
Fenestrated capillary
Discontinous/ sinusoidal capillary
Explain Continous capillaries:
endothelial cells
basal lamina
found where?
Continous Capillaries
- continous endothelial cells
- continous basal lamina
- MOST common type of capillary, found in skeletal muscle, CNS, skin, lung, connective tissue
Explain Fenestrated capillaries:
endothelial cells
basal lamina
found where?
Fenestrated capillaries:
- continous endothelial cells with fenestrations (holes) with or without diaphragms
- continous basal lamina
- found in kidney and intestines
Explain discontinous/sinusodial capillaries:
endothelial cells
basal lamina
found where?
Discontinous/sinusodial capallaries:
discontinous endothelial cells
discontinous basal lamina
found in liver, bone marrow and spleen
If capallaries have the largest CSA (cross sectional area), why do they have such a low blood volume?
Capallaries are short
Arteries and artieroles have ____ compliance ___ pressure
Veins and venules have ___ compliance and ___ pressure
Arteries: LOW compliance, high pressure
Veins: HIGH compliance, low pressure
Resistance progressively increases and is the largest at the _____. Therefore, the largest drop in pressure is across the _______.
Although capillaries have such a small diameter, the capallaries have the largest total cross sectional area, which means that have the _______ total resistance
Resistance progressively increases and is the largest at the arterioles. Therefore, the largest drop in pressure is across the arterioles.
Capallaries have small diameters, but they have the largest total CSA, so they have the lowest total resistance (think about it there are so many options, aka least amount of resistance)
Think about that graph on how pressure changes from the aorta —> large arteries to arterioles and down.
Draw it
Compared to the aorta, the blood pressure if you measured it in the large arteries would be ____ (smaller or larger)?
Compared to the aorta, blood pressure increases in the large arteries because the large artieries are less compliant than the aorta
Define the “Pulse Pressure”
What does the pulse pressure indicate about the heart?
Define “Mean Arterial Pressure”
“Pulse Pressure” is the difference between systolic and diastolic pressure (it indicates the strength of contraction of the heart)
“Mean Arterial Pressure” is the average pressure existing in the aorta and the proximal arterial system during one cardiac cycle
MAP = 1/3 sysolic + 2/3 diastolic
Pulse pressure ___ in vessels further from the heart
Mean Arterial Pressure _____ throughout the circulatory system
Pulse pressure widens in vessels further from the heart
MAP continously declines throughout the circulatory system
Mean Arterial Pressure is determined more by ____ than ___ pressure
What is the pulse pressure in the capallaries and the veins?
MAP is determined more by diastolic than by systolic
There is no pulse pressure in capallaries and veins
Explain how the hydraulic/windkessel filter works in a normally functioning aorta
Explain systole and diastole
During systole, a substantial volume of ejected blood is stored by the distension of the elastic vascular component of the aorta itself
During diastole: the distended aortic wall recoils and acts as a secondary pump to maintain constant capillary flow during diastole
The hydraulic filter/windkessel filter is dependent on ________
Hydraulic/Windkessel Filter is dependent on the compliance of the aortic wall
How does the heart maintain constant capillary flow during diastole?
Through the hydraulic/ windkessel filter in the aorta
Explain what happens in the hydraulic filter/windkessel filter for RIGID ARTERIES with low compliance
Rigid Arteries with low compliance…. Hydraulic Filter
During Systole/ejection, very little blood can be stored in the aorta, and must flow directly downstream increasing the systolic pressure
During diastole, there is no elastic recoil, causing discontinous flow and a decrease in diastolic pressure
Aortic compliance decreases with age because of less ____ and more ____.
As compliance decreases, a given increase in volume elicits a ______
Aortic compliance decreases with age, because of less elastin and more collagen (stiff)
As compliance decreases, a given increase in volume elicits a larger increase in pressure.
Less compliant aorta, means ______ pulse pressure and ___ cardiac work and ____ oxygen consumption
An increase in PP is an independent risk factor for development of ______
Less compliant aorta means INCREASE in pulse pressure, thus increasing cardiac work and increasing oxygen consumption
Increase in PP is independent risk factor for heart failure
Exercise _____ arterial compliance
Exercise increases arterial compliance
The arterial pressure pulse (wave) travels down the aorta at ___ m/s in aorta and __ m/s in arteries.
In contrast, the flow of blood is __ m/s.
Increases in pulse pressure will cause an _____ in pressure pulse.
Arterial pressure wave travels down aorta at 5 m/s and down arteries at 10-15 m/s.
Blood travels at 1 m/s
Therefore the pressure pulse travels faster than blood
Increase in pulse pressure will cause an increase in the pressure pulse.
As compliance decreases down the arterial tree, the velocity of the propogation of the pressure pulse ___
Pressure pulse can be measured at multiple sites to estimate _____
A faster PWV means ______
As compliance decreases down the arterial tree, the velocity of the propogation of the pressure pulse INCREASES.
Pressure pulse can be measured at multiple sites to estimate arterial compliance
Faster PWV means stiffer vessels from age, hypertension, etc.
