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Physiology > 29. Morphology of blood vessels, Heart sounds, blood pressure > Flashcards

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

1
Q

When do each of the heart sounds occur

A

1st: Occurs at the start of ventricular systole

2nd: Occurs at start of ventricular diastole

3rd: Occurs at ventricular diastole

4th: During atrial systole

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2
Q

How is the 1st heart sound generated

A

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
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3
Q

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

A

90-150ms

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

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4
Q

How is the 2nd heart sound generated

A

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.

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5
Q

How long is 2nd heart sound
Characteristics

A

10-120ms

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

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6
Q

How is 3rd heart sound generated

A

Rarely ausculated

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

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7
Q

How long is 3rd heart sound
characteristics

A

100ms

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

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8
Q

How is the 4th heart generated

A

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

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9
Q

How long is 4th heart sound
Characteristics

A

40-80ms

Low intensity low frequency ( <20Hz)

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10
Q

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

A

Frequency too low

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11
Q

Under what conditions can you hear the 3rd heart sound

A

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

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12
Q

What is the benchmark for auscultation

A

sternal angle
coincides with 2nd rib attachment

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13
Q

What are the main auscultation points

A

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

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14
Q

What is phonocardiogram

A

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

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15
Q

What is a phonocardiogram always registered with

A

an ECG

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16
Q

How does phonocardiogram work

A

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

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17
Q

What is auscultation gap

A

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

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18
Q

What are buffering blood vessels

A

Large arteries and aorta

Elastic and collagen fibers in their walls dampen pressure fluctuations

19
Q

What are Resistance vessels

A

Arterioles

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

Important in maintaining diastolic arterial pressure

20
Q

What are exchange vessels

A

Capillaries and thin wall venules

Exchange of intracellualr fluid and plasma components takes place across walls

21
Q

What are capacitance vessels

A

Veins

Contain most of the blood volume

Changes diameter easily thus alter blood distribution

22
Q

What are the 2 things circulation depends on

A

1, pressure gradient

  1. Vascular resistance that should be overcome to allow blood flow
23
Q

What is blood flow

A

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

24
Q

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

A

Q=∆P/R

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

25
Q

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

A

Q=∆Pπr4/8ηl

Poiseuilles law

26
Q

What is the property viscosity of blood
What are the factors

A

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

27
Q

What is linear velocity of blood

A

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

28
Q

Why is changes in the radius of the vessel important

A

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.

29
Q

Vascular resistance in SEQUENTIALLY connected blood vessels

A

The sum of the individual vessel resistances

These are the arrangement of vessels within an organ

major artery~smaller arteries~arterioles~capillaries~venules~veins

30
Q

Vascular resistance in PARALLELL connected blood vessels

A

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.

31
Q

Adv of parallel connected vessels

A

RESISTANCE IN PARALLEL LESS THAN IN SEQUENTIAL

32
Q

What is vascular compliance
Differecne between venous and arterial

A

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

33
Q

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

A

No stopping due to elastic properties of the arteries

In systole they dilate then in diastooe it narrows to normal diameter

34
Q

How is pulse wave generated

A

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

35
Q

What is the cause of blood pressure

A

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.

36
Q

What is systolic, diastolic, pulse blood pressure

A

Systolic is detected at systole, max blood pressure

Diastolic is detected at diastole, minimum blood pressure

Pulse pressure = systolic- distolic

37
Q

What is mean arterial blood pressure MaP

A

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

38
Q

What are the major factros determining arterial Blood pressure

A

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.

39
Q

What are some methods of measuring blood pressure

A

Invasive by inserting a catheter with a pressuretransducer into the artery.

  1. 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.

40
Q

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

A

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

41
Q

What causes Korotkoff sounds (auscultation method)

A

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

42
Q

What is optimal values of blood pressure

What is normal blood presrue

A

systolic= 100-119 mmHg

diastolic= 60-79 mmHg

systolic= 120-129mmHg

diastolic=80-84 mmHg

43
Q
A

Physiology (20 decks)

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