29. Morphology of blood vessels, Heart sounds, blood pressure

Question 1

When do each of the heart sounds occur

Answer 1

1st: Occurs at the start of ventricular systole

2nd: Occurs at start of ventricular diastole

3rd: Occurs at ventricular diastole

4th: During atrial systole

Question 2

How is the 1st heart sound generated

Answer 2

3 components

• Valve component- rapid closure of atrio-ventricular valves (mitral closes before tricuspid)
• Muscular component- Vibrations in ventricular walls during isovolumetric contraction
• Vascular component- Vibrations in walls of large arterial vessels ie aorta/pulmonary artery
  Generated at very beginning of ejection phase when semilunar valves open

Question 3

How long is the 1st heart sound
What are its characteristics

Answer 3

90-150ms

Louder and lower pitch than 2nd bc oscillations have larger intensity and lower frequency (50-60 Hz)

Question 4

How is the 2nd heart sound generated

Answer 4

Vibrations caused by closure of semilunar valves (aorta/pulmonary artery)

Aortic valve closes before pulmonary valve so physiological bifurcation of the heart sound is observed

During deep expiration the delay in pulmonary valve closer is
up to 0.02 sec., while in deep inspiration is up to 0.06 sec.

Question 5

How long is 2nd heart sound
Characteristics

Answer 5

10-120ms

Lower intensity and higher frequency (80-90Hz) than 1st

Question 6

How is 3rd heart sound generated

Answer 6

Rarely ausculated

Vibrations of ventricular walls caused by influx of a lot of blood during rapid filling phase

Question 7

How long is 3rd heart sound
characteristics

Answer 7

100ms

Low intensity and low frequency (20-30Hz) therefore hard to hear

Question 8

How is the 4th heart generated

Answer 8

Blood flow acceleration due to atrial systole (end filling phases of ventricles)

Question 9

How long is 4th heart sound
Characteristics

Answer 9

40-80ms

Low intensity low frequency ( <20Hz)

Question 10

Why cant the 3rd and 4th heart sounds be detected with auscultation

Answer 10

Frequency too low

Question 11

Under what conditions can you hear the 3rd heart sound

Answer 11

In children and adolescents after physical exercise since blood flow is more rapid in those ages, acceleration of blood flow

Question 12

What is the benchmark for auscultation

Answer 12

sternal angle
coincides with 2nd rib attachment

Question 13

What are the main auscultation points

Answer 13

To hear:

Mitral valve: located 5th intercostal space, .5cm lateral (left) of midsternal line . HEAR 1ST HEART SOUND

Pulmonary valve: 2nd intercostal space onleft. HEAR 2ND HEART SOUND

Aortic valve: 2nd intercostal space on right HEAR 2nd HEART SOUND

Tricuspid valve: 5th rib next to sternal edge on right. 1ST HEART SOUND

Erbs point: 3rd left intercostal space, left sternal edge

Question 14

What is phonocardiogram

Answer 14

objective graphical method for registration of all cardiac sounds
occurring during the work of the heart, regardless of their intensity and
frequency.

Question 15

What is a phonocardiogram always registered with

Answer 15

an ECG

Question 16

How does phonocardiogram work

Answer 16

Heart sounds are detected by
microphone placed on the auscultation
points and a transducer afterwards turns
the sound waves into electrical waves.

Question 17

What is auscultation gap

Answer 17

Temporary disappearance of Korotkoff sounds because greater external pressure was applied when taking the blood pressure or very slow opening of the pressure valve

Auscultation gap can result in detection of lower than actual systolic
pressure or higher than actual diastolic pressure

Question 18

What are buffering blood vessels

Answer 18

Large arteries and aorta

Elastic and collagen fibers in their walls dampen pressure fluctuations

Question 19

What are Resistance vessels

Answer 19

Arterioles

Lots of smooth muscle they can chnage their diameter to exert avrapidly changing resistance to blood flow

Important in maintaining diastolic arterial pressure

Question 20

What are exchange vessels

Answer 20

Capillaries and thin wall venules

Exchange of intracellualr fluid and plasma components takes place across walls

Question 21

What are capacitance vessels

Answer 21

Veins

Contain most of the blood volume

Changes diameter easily thus alter blood distribution

Question 22

What are the 2 things circulation depends on

Answer 22

1, pressure gradient

2. Vascular resistance that should be overcome to allow blood flow

Question 23

What is blood flow

Answer 23

Blood flow is the volume of blood passed per
second through a given area of ​​the vascular
system.

It is measured in ml/s.

Blood fow caused by pressure gradient and vascular resistance due to pumping action of heart

Question 24

What is the equation linking blood flow, pressure gradient, resistance

Answer 24

Q=∆P/R

Blood flow (Q) is directly proportional to the
pressure gradient (∆P) and inversely
proportional to vascular resistance (R):

Question 25

What equation can you use for laminar flow when blood flow in parallele layers

Answer 25

Q=∆Pπr4/8ηl Poiseuilles law

Question 26

What is the property viscosity of blood What are the factors

Answer 26

When fluid particles exert internal friction during laminar flow Depends on the number of cells, and content of the plasma proteins when viscosity low= anaemia and hypoproteinemia

Question 27

What is linear velocity of blood

Answer 27

Linear velocity of the blood is defined as the distance that each particle of the blood travels through a blood vessel per unit time. It is measured in cm/s. V=Q/A porportional to blood flow, inversel to cross sectional area

Question 28

Why is changes in the radius of the vessel important

Answer 28

r^4 When the radius of a vessel (r) decreases due to vasoconstriction or partial occlusion, an increase in vascular resistance (R) and a decrease in blood flow (Q) are observed.

Question 29

Vascular resistance in SEQUENTIALLY connected blood vessels

Answer 29

The sum of the individual vessel resistances These are the arrangement of vessels within an organ major artery~smaller arteries~arterioles~capillaries~venules~veins

Question 30

Vascular resistance in PARALLELL connected blood vessels

Answer 30

Sum of reciprocal values ​​of individual vessels resistances This is the distribution of blood from major arteries coming from aorta renal circulation, cerebral circulation, and coronary circulation.

Question 31

Adv of parallel connected vessels

Answer 31

RESISTANCE IN PARALLEL LESS THAN IN SEQUENTIAL

Question 32

What is vascular compliance Differecne between venous and arterial

Answer 32

Stetchability of the vessel The compliance of arterial system is significantly smaller than the compliance of the venous system. Meaning same change in blood volume leads to smaller pressure increase in venous vessels that arteries

Question 33

Why does blood flow not stop in diastole when pressure in ventricles is 0

Answer 33

No stopping due to elastic properties of the arteries In systole they dilate then in diastooe it narrows to normal diameter

Question 34

How is pulse wave generated

Answer 34

It is generated by deformation (dilation) of the aortic wall during ventricular systole which is transmitted along the arterial system.

Question 35

What is the cause of blood pressure

Answer 35

It is caused by pumping out of relatively large volume of blood for the size of aorta during ventricular systole and the resistance that the blood encounters as it moves in the vascular system.

Question 36

What is systolic, diastolic, pulse blood pressure

Answer 36

Systolic is detected at systole, max blood pressure Diastolic is detected at diastole, minimum blood pressure Pulse pressure = systolic- distolic

Question 37

What is mean arterial blood pressure MaP

Answer 37

All pressure values during 1 cardiac cycle since diastole is longer than systole, it contributes greater to the MaP Calculated by: diastolic pressure + 1/3 Pulse pressure

Question 38

What are the major factros determining arterial Blood pressure

Answer 38

Stroke Volume (SV). Cardiac Output (CA). Total vascular resistance (TVR). The compliance (extensibility) of the vessels. Ratio between speed of ejection and TVR. Circulating volume of blood.

Question 39

What are some methods of measuring blood pressure

Answer 39

Invasive by inserting a catheter with a pressuretransducer into the artery. 2. Indirect sphygmomanometric method by applying of external pressure on brachial artery: Palpatory - based on appearance of pulsation on radial artery (method of Riva - Rocci). Auscultatory - based on appearance of sound phenomena (the sounds of Korotkoff) upon auscultation of brachial artery. Oscillatory - detection of the oscillations in the wall of brachial artery.

Question 40

Why brachial systolic pressure measured with the palpation method of Riva-Rocci is lower than the value assessed with the auscultation method?

Answer 40

Due to delay of the pulse wave. First the pulse wave appear on brachial artery and afterwards on the radial artery.

Question 41

What causes Korotkoff sounds (auscultation method)

Answer 41

TURBULENT flow in brachaial aretry by reducing external cuff pressure Lumen of artery only partially open so high blood velocity causes change fromlaminar to turbuelnt

Question 42

What is optimal values of blood pressure What is normal blood presrue

Answer 42

systolic= 100-119 mmHg diastolic= 60-79 mmHg systolic= 120-129mmHg diastolic=80-84 mmHg