Section 2

Question 1

What are the two primary functions of arteries?

Answer 1

1. As rapid-transit passageways for blood due to their larger radius.
2. As pressure reservoirs to make sure a pressure gradient exists even when the heart is relaxing

Question 2

Why are the walls of major arteries thick?

Answer 2

The walls of major arteries are thick due to the presence of a significant amount of elastin fibers in the connective tissue layers on both sides of the smooth muscle cells.

Question 3

What is the role of elastin fibers in major arteries?

Answer 3

Elastin fibers in major arteries allow them to act as a pressure reservoir.

Question 4

Define systole in the context of the heartbeat.

Answer 4

Systole refers to the phase of the heartbeat characterized by the contraction and blood ejection from the chambers of the heart.

Question 5

Define diastole in the context of the heartbeat.

Answer 5

Diastole refers to the phase of the heartbeat characterized by the relaxation of the heart chambers and the refilling of blood into these chambers.

Question 6

What happens during systole in a heartbeat?

Answer 6

During systole, the left ventricle contracts, ejecting pressurized blood into the aorta.

Question 7

How does the volume of blood ejected during systole affect artery walls?

Answer 7

The volume of blood ejected during systole is greater than the rate at which blood is flowing through the capillaries, causing the ejected blood to stretch the artery walls outward.

Question 8

What role does the pressure generated by the heart during systole play in sustaining arterial pressure during diastole?

Answer 8

The pressure generated by the heart during systole is transferred to the artery walls, sustaining arterial pressure during cardiac diastole.

Question 9

When does maximum blood pressure occur, and what is it called?

Answer 9

Maximum blood pressure occurs during systole when blood is ejected from the heart. This pressure is called systolic pressure, and in a healthy individual, it is around 120 mmHg.

Question 10

What characterizes the state of the aortic valve during diastole?

Answer 10

During diastole, the aortic valve is closed, preventing blood flow into the aorta.

Question 11

How does blood flow to the capillaries occur during diastole?

Answer 11

Blood flow to the capillaries continues during diastole, facilitated by the passive recoil of the elastic artery walls.

Question 12

What is passive recoil, and how does it contribute to blood flow during diastole?

Answer 12

Passive recoil is the process during diastole where the elastic artery walls, which were stretched outward during systole, undergo a return to their un-stretched state. This recoil exerts a squeezing force on the blood within the arteries, helping to maintain higher arterial pressure and a pressure gradient for flow.

Question 13

What happens to the volume of blood and pressure in the arteries during diastole?

Answer 13

During diastole, as blood continues to move through the capillaries, the volume of blood in the arteries decreases, leading to a drop in pressure. The pressure reaches its minimum, known as diastolic pressure, which is around 80 mmHg.

Question 14

How can blood pressure be measured?

Answer 14

Blood pressure can be measured using either an automated blood pressure monitor or a sphygmomanometer, which is an inflatable cuff with a pressure gauge and a stethoscope.

Question 15

Describe the process of measuring blood pressure using a sphygmomanometer.

Answer 15

The inflatable cuff is wrapped around the upper arm and inflated with air to a pressure above systolic pressure. This pressure is transferred through the arm to the brachial artery, and the sounds of blood flow during this process are called Korotkoff sounds.

Question 16

What artery is typically involved in measuring blood pressure using a sphygmomanometer?

Answer 16

The brachial artery, which is the major artery carrying blood to the forearm, is typically involved in measuring blood pressure using a sphygmomanometer.

Question 17

What are the sounds of blood flow during the process of measuring blood pressure called?

Answer 17

The sounds of blood flow during the process of measuring blood pressure are called Korotkoff sounds.

Question 18

How are Korotkoff sounds used to determine blood pressure?

Answer 18

Korotkoff sounds are created by inflatable cuffs on sphygmomanometers, and they produce audible patterns of sounds that help identify systolic and diastolic pressures.

Question 19

What happens when the cuff pressure is greater than 120 mmHg?

Answer 19

When the cuff pressure is greater than 120 mmHg, it exceeds blood pressure throughout the cardiac cycle, resulting in no blood flow and hence no sound being heard.

Question 20

Describe the situation when the cuff pressure is between 120 and 80 mmHg.

Answer 20

When cuff pressure is between 120 and 80 mmHg, blood flow through the vessel is turbulent whenever blood pressure exceeds cuff pressure. The first sound is heard at peak systolic pressure, followed by intermittent sounds as turbulent spurts of flow occur when blood pressure cyclically exceeds cuff pressure.

Question 21

What occurs when the cuff pressure is less than 80 mmHg?

Answer 21

When the cuff pressure is less than 80 mmHg, and thus below blood pressure during the cardiac cycle, blood flows through the vessel in a smooth, laminar fashion. The last sound is heard at minimum diastolic pressure, and there are no sounds to follow due to smooth, uninterrupted, laminar flow.

Question 22

Define “laminar” and “turbulent” in the context of fluid movement.

Answer 22

“Laminar” refers to smooth, regular movement of fluid, while “turbulent” describes uneven, irregular movement of fluid.

Question 23

What is the pulse pressure?

Answer 23

The difference between the systolic and diastolic pressures.

This represents the pressure change during that cardiac cycle.

Question 24

What is the mean arterial pressure?

Answer 24

(MAP)
The average pressure during the cardiac cycle; represents the mean driving force for blood flow throughout the rest of the vascular system.

Question 25

How is mean arterial pressure (MAP) calculated?

Answer 25

Mean arterial pressure (MAP) is calculated as diastolic pressure plus 1/3 of pulse pressure.

Question 26

Define pulse pressure.

Answer 26

Pulse pressure is defined as the difference between systolic pressure and diastolic pressure.

Question 27

During a cardiac cycle at rest, how much time does the heart spend in diastole and systole, respectively?

Answer 27

During a cardiac cycle at rest, the heart spends about 2/3 of the time in diastole and only 1/3 in systole.

Question 28

Provide the formula for calculating pulse pressure.

Answer 28

Pulse pressure = systolic pressure - diastolic pressure

Question 29

Using the given example values (systolic = 120 mmHg, diastolic = 80 mmHg), calculate the mean arterial pressure (MAP) and pulse pressure.

Answer 29

For the given example:
MAP = 80 + 1/3(40) = 93 mmHg
Pulse pressure = 120 - 80 = 40 mmHg

Question 30

What happens to the pressure generated by the heart as it is transferred from the ventricles to the large arteries?

Answer 30

The pressure generated by the heart in the ventricles is transferred to the large arteries, where cyclical changes in pressure, known as pulse pressure, still occur.

Question 31

How is the cyclical nature of blood pressure transformed as it reaches the arterioles?

Answer 31

at the level of the arterioles, the cyclical nature of blood pressure is converted into a non-pulsatile pressure.

Question 32

What is the purpose of converting blood pressure into a non-pulsatile pressure before entering the capillaries?

Answer 32

The conversion of blood pressure into a non-pulsatile pressure before entering the capillaries is aimed at making nutrient/waste exchange more efficient.

Question 33

Why is non-pulsatile pressure necessary in the smaller blood vessels and capillaries?

Answer 33

Non-pulsatile pressure is necessary in smaller blood vessels and capillaries because, although the diameter of an individual capillary is significantly smaller than that of an arteriole, the greater cross-sectional area of capillaries, due to their abundance, helps maintain blood pressure and velocity of blood flow, making nutrient/waste exchange more efficient.