Exam 3 Kirk Lecture Systemic Circulation

Question 1

Vessles are primarily composed of:

1.

2.

3.

4.

Answer 1

Vessels are primarily composed of:

elastin

collagen

smooth muscle

endothelial cells

Question 2

________ is a change in pressure caused by a given change in volume

At low pressures, veins are _____ than arteries

Answer 2

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)

Question 3

Arteries have ____ compliance, therefore they are considered ____ vessels

Answer 3

Arteries have very low compliance, and they are considered resistance vessels

Question 4

Comparing Arteries to Veins:

a) artery has _____, veins do not
b) artery has ____ smooth muscle than veins
c) artery has ____ connective tissue than veins

Answer 4

Arteries have elastic lamina (both internal and external), vein’s don’t

Arteries have more smooth muscle than veins

Arteries have less connective tissue

Question 5

What kind of valves do veins have?

Answer 5

veins have one way valves (unidirectional)

Question 6

Rate the following in terms of highest to lowest compliance:

smooth muscle

collagen

elastic lamina

Answer 6

Highest compliance to lowest:

elastic lamina > smooth muscle > collagen

Question 7

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.

Answer 7

Arteries: low complaiance, resistance vessels

Veins: high compliance, capacitance vessels

Question 8

At higher pressures, the compliance of veins is __

Answer 8

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

Question 9

Label this diagram

What is it? Label 1, 2, 3, and 4

Answer 9

Large elastic artery:

1. Endothelium
2. Internal Elastic Laminae
3. Tunica Media
4. Tunica Adventia (this is where small blood vessels called vasa vasocorum are located)

Question 10

For a given stroke volume into the aorta, the aortic pulse pressure is _____ when compliance decreases

Answer 10

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

Question 11

What are the three types of capillaries?

Answer 11

Three types of capillaries:

Continous capillary

Fenestrated capillary

Discontinous/ sinusoidal capillary

Question 12

Explain Continous capillaries:
endothelial cells

basal lamina

found where?

Answer 12

Continous Capillaries

• continous endothelial cells
• continous basal lamina
• MOST common type of capillary, found in skeletal muscle, CNS, skin, lung, connective tissue

Question 13

Explain Fenestrated capillaries:

endothelial cells

basal lamina

found where?

Answer 13

Fenestrated capillaries:

• continous endothelial cells with fenestrations (holes) with or without diaphragms
• continous basal lamina
• found in kidney and intestines

Question 14

Explain discontinous/sinusodial capillaries:

endothelial cells

basal lamina

found where?

Answer 14

Discontinous/sinusodial capallaries:

discontinous endothelial cells

discontinous basal lamina

found in liver, bone marrow and spleen

Question 15

If capallaries have the largest CSA (cross sectional area), why do they have such a low blood volume?

Answer 15

Capallaries are short

Question 16

Arteries and artieroles have ____ compliance ___ pressure

Veins and venules have ___ compliance and ___ pressure

Answer 16

Arteries: LOW compliance, high pressure

Veins: HIGH compliance, low pressure

Question 17

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

Answer 17

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)

Question 18

Think about that graph on how pressure changes from the aorta —> large arteries to arterioles and down.

Draw it

Answer 18

Question 19

Compared to the aorta, the blood pressure if you measured it in the large arteries would be ____ (smaller or larger)?

Answer 19

Compared to the aorta, blood pressure increases in the large arteries because the large artieries are less compliant than the aorta

Question 20

Define the “Pulse Pressure”

What does the pulse pressure indicate about the heart?

Define “Mean Arterial Pressure”

Answer 20

“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

Question 21

Pulse pressure ___ in vessels further from the heart

Mean Arterial Pressure _____ throughout the circulatory system

Answer 21

Pulse pressure widens in vessels further from the heart

MAP continously declines throughout the circulatory system

Question 22

Mean Arterial Pressure is determined more by ____ than ___ pressure

What is the pulse pressure in the capallaries and the veins?

Answer 22

MAP is determined more by diastolic than by systolic

There is no pulse pressure in capallaries and veins

Question 23

Explain how the hydraulic/windkessel filter works in a normally functioning aorta

Explain systole and diastole

Answer 23

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

Question 24

The hydraulic filter/windkessel filter is dependent on ________

Answer 24

Hydraulic/Windkessel Filter is dependent on the compliance of the aortic wall

Question 25

How does the heart maintain constant capillary flow during diastole?

Answer 25

Through the hydraulic/ windkessel filter in the aorta

Question 26

Explain what happens in the hydraulic filter/windkessel filter for RIGID ARTERIES with low compliance

Answer 26

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

Question 28

Aortic compliance decreases with age because of less ____ and more ____.

As compliance decreases, a given increase in volume elicits a ______

Answer 28

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.

Question 29

Less compliant aorta, means ______ pulse pressure and ___ cardiac work and ____ oxygen consumption

An increase in PP is an independent risk factor for development of ______

Answer 29

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

Question 30

Exercise _____ arterial compliance

Answer 30

Exercise increases arterial compliance

Question 31

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.

Answer 31

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.

Question 32

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 ______

Answer 32

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.