Pressure & Flow In Arteries & Veins 1

Question 1

Describe how arterial pressure can be measured using an line.

Answer 1

terial pressure can measured using an arterial line, which is a thin catheter inserted into an artery, typically the radial artery at the wrist or the brachial artery at the elbow.

Question 2

Define auscultation in the context of measuring blood pressure.

Answer 2

Auscultation is the act of listening for Korotkoff sounds using a stethoscope and sphygmomanometer to measure blood pressure.

Question 3

How are Korotkoff sounds described in relation to blood flow?

Answer 3

Korotkoff sounds are described as turbulent blood flow heard through a stethoscope when blood starts spurring through the artery as cuff pressure falls below systolic pressure.

Question 4

Describe the components of a sphygmomanometer.

Answer 4

A sphygmomanometer consists of an inflatable cuff placed around the upper arm, a pump to increase pressure in the cuff, a pressure gauge showing pressure in mmHg, and a valve to release pressure.

Question 5

Define laminar flow in the context of blood flow.

Answer 5

Laminar flow refers to smooth, uninterrupted blood flow in an artery without turbulence.

Question 6

How is diastolic pressure related to Korotkoff sounds during blood pressure measurement?

Answer 6

When cuff pressure falls below diastolic pressure, normal laminar blood flow is restored, and Korotkoff sounds cease to be heard.

Question 7

Describe the significance of the peak and trough in an arterial pressure wave.

Answer 7

The peak represents systolic blood pressure, while the trough represents diastolic pressure in an arterial pressure wave.

Question 8

How does the cuff pressure relate to the occurrence of Korotkoff sounds during blood pressure measurement?

Answer 8

Korotkoff sounds are heard when cuff pressure falls below systolic pressure, allowing blood to spurt through the artery, creating turbulent flow and audible sounds.

Question 9

Describe the process of measuring blood pressure with a manual sphygmomanometer.

Answer 9

The process involves listening for Korotkoff sounds, which indicate the pressure in the arteries. The sounds change as the pressure cuff is slowly deflated, allowing for the determination of systolic and diastolic pressures.

Question 10

Define Korotkoff sounds.

Answer 10

These are the sounds heard through a stethoscope when measuring blood pressure with a manual sphygmomanometer. They indicate the flow of blood through the arteries as the pressure cuff is deflated.

Question 11

How do automatic blood pressure machines differ from manual sphygmomanometers?

Answer 11

Automatic machines measure oscillations in the arteries instead of Korotkoff sounds. They use these vibrations to calculate mean arterial pressure and estimate systolic and diastolic pressures.

Question 12

Describe the process by which automatic blood pressure machines calculate blood pressure.

Answer 12

These machines detect oscillations in the arteries, find the peak vibrations as the mean arterial pressure, and use algorithms to estimate systolic and diastolic pressures.

Question 13

What is the role of the aorta in the measurement of arterial pressure?

Answer 13

The aorta acts as a pressure reservoir during systole when blood is ejected into it, and during diastole, its elastic recoil helps maintain blood flow by pushing on the column of blood.

Question 14

Do different brands of automatic blood pressure machines provide the same measurements?

Answer 14

Different brands may use slightly different algorithms, leading to slightly varied measurements. However, they generally have similar advantages and disadvantages.

Question 15

How does the accuracy of manual blood pressure measurements get affected?

Answer 15

The accuracy can be subjective due to factors like background noise, stethoscope fit, and individual hearing abilities. This subjectivity can lead to discrepancies in recorded blood pressure values.

Question 16

Describe the advantages of using automatic blood pressure machines.

Answer 16

Automatic machines are non-invasive, cost-effective, easier to use, and quicker than manual sphygmomanometers. They provide continuous measurements and require less user skill for accurate readings.

Question 17

Describe the components of a typical pressure in the cardiovascular system.

Answer 17

The wave includes a steep phase, peak systolic blood pressure, a dicrotic notch caused by aortic valve closure, a gradual falling phase due to aortic elasticity.

Question 18

How does stroke volume influence the pressure wave in the cardiovascular system?

Answer 18

Increased contractility and pumping force lead to a more rapid rising phase and higher systolic pressure.

Question 19

Define the impact of arterial elasticity on the pressure wave.

Answer 19

Decreased elasticity with age causes systolic pressure to rise and diastolic pressure to fall due to reduced pressure reservoir function.

Question 20

What role does total peripheral resistance play in the pressure wave?

Answer 20

It affects the falling phase post-aortic valve closure, with higher resistance leading to a more gradual fall and higher diastolic pressure.

Question 21

Describe the effect of arteriole constriction on the pressure wave.

Answer 21

Constriction increases total peripheral resistance, resulting in a more gradual falling phase and higher diastolic pressure.

Question 22

How does arteriole dilation impact the pressure wave in the cardiovascular system?

Answer 22

Dilation reduces total peripheral resistance, leading to a steeper falling phase and lower diastolic pressure.

Question 23

Describe how blood pressure changes with age.

Answer 23

Blood pressure tends to rise as individuals age due to factors like the loss of elasticity in blood vessels.

Question 24

Define mean arterial pressure.

Answer 24

Mean arterial pressure is the average pressure in a person’s arteries during one cardiac cycle.

Question 25

How does blood pressure vary within an individual throughout the day?

Answer 25

Blood pressure can vary throughout the day, being lower during sleep, higher in the morning, and showing spikes in response to stimuli like pain or arousal.

Question 26

Do arterioles act as resistance vessels?

Answer 26

Yes, arterioles are considered resistance vessels due to their narrow lumen and thick muscular walls that can be contracted or relaxed to regulate blood flow.

Question 27

Describe the pressure changes as blood flows through the vascular tree.

Answer 27

Pressure decreases as blood moves from the left ventricle to the arteries, arterioles, capillaries, veins, and venules, with the highest pressure in the arteries and the lowest in the right atrium.

Question 28

How do capillaries differ from arteries and arterioles in terms of pressure?

Answer 28

Capillaries have low pressure (about 40 mmHg) compared to arteries and arterioles, as they are thin-walled and delicate structures.

Question 29

Define systemic filling pressure.

Answer 29

Systemic filling pressure is the difference in pressure between the veins and venules (about 20 mmHg) and the right atrium (about 5 mmHg), indicating the pressure gradient for blood return to the heart.

Question 30

Describe the role of arterioles in regulating total peripheral resistance.

Answer 30

Arterioles can constrict or dilate based on muscle contraction, thereby influencing total peripheral resistance and blood flow through the vascular system.

Question 31

Do arteries have low or high resistance to blood flow?

Answer 31

Arteries have low resistance to blood flow due to their wide lumen, facilitating the smooth flow of blood from the heart to the arterioles.

Question 32

Describe the relationship between pressure and the systemic versus pulmonary circulation.

Answer 32

Pressure is much lower in the pulmonary circulation compared to the systemic circulation due to the need for lower pressures to pump blood through the lungs.

Question 33

Define velocity in the context of blood flow through the vascular tree.

Answer 33

Velocity refers to the speed at which blood moves through the vascular system, with variations in velocity observed in different parts of the circulatory system.

Question 34

How does the total cross-sectional area affect blood velocity in the circulatory system?

Answer 34

Blood velocity is inversely related to the total cross-sectional area; areas with larger total cross-sectional areas, like capillaries, have lower blood velocities.

Question 35

Describe the analogy used to explain the total cross-sectional area of capillaries.

Answer 35

Capillaries are compared to strands of spaghetti, where each individual capillary is like a strand, and the total cross-sectional area is large due to the presence of many capillaries.

Question 36

Do the vena cavae have high or low blood velocity, and why?

Answer 36

The vena cavae have high blood velocity because despite having two of them, their total cross-sectional area is small, leading to faster blood flow.

Question 37

Explain the concept of ‘still waters run deep’ in relation to hemodynamics.

Answer 37

In hemodynamics, ‘still waters run deep’ means that where there is a large total cross-sectional area, like in deep waters, blood velocity is low; conversely, in areas with small cross-sectional areas, like rapids, blood velocity is high.