HEALTH ASSESSMENT LECTURE – WEEK 8.2 HEART AND CENTRAL VESSELS
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WEEK 8.2 – HEART AND CENTRAL
VESSELS
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THE HEART
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The main function of the heart is to
circulate blood through the body and
lungs.
STRUCTURE:
1. PERICARDIUM
- Tough, double-walled, fibrous
sac encasing and protecting the
heart.
 Several milliliters of fluid are present
between the inner and outer layers
of the pericardium, providing for low
friction.
2. MYOCARDIUM
- Thick, muscular middle layer
responsible for pumping.
3. ENDOCARDIUM
- Innermost layer, lining chambers
and covering valves.
CHAMBERS AND VALVES
THE AV VALVES
Two AV valves separate atria and ventricles
- TRICUSPID VALVE: right AV
valve
- BICUSPID, OR MITRAL
VALVE: left AV valve
- Valves’ thin leaflets are
anchored by collagenous fibers
(chordae tendineae) to papillary
muscles embedded in ventricle
floor.
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2 upper chambers the RIGHT
AND LEFT ATRIA
2 LOWER CHAMBERS:
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RIGHT AND LEFT
VENTRICLES
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Valves are unidirectional: can
only open one way.
Valves open and close
passively in response to
pressure gradients in
moving blood.
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FOUR VALVES IN HEART
AV valves open during heart’s
filling phase, or diastole, to allow
ventricles to fill with blood.
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During pumping phase, or
systole, AV valves close to
prevent regurgitation of blood
back up into atria.
THE SEMILUNAR VALVES
SL valves are set between ventricles and
arteries.
Four chambers separated by valves, whose
main purpose is to prevent backflow of
blood.
4 CHAMBERS:
Two atrioventricular
(AV) valves
Two semilunar (SL)
valves
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Each valve has three cusps that
look like half-moons.
PULMONIC VALVE: SL valve in right side
of heart.
AORTIC VALVE: SL valve in left side of
heart
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Open during pumping, or systole,
to allow blood to be ejected from
heart.
Abnormally high pressure in left
side of heart gives a person
symptom of pulmonary
congestion.
Abnormally high pressure in right
side of heart shows in neck veins
and abdomen
VALVES: permit the flow of blood in only
one direction.
HEALTH ASSESSMENT LECTURE – WEEK 8.2 HEART AND CENTRAL VESSELS
ATRIOVENTRICULAR:
Tricuspid valve, which has three
cusps (or leaflets), separates the right
atrium from the right ventricle.
Mitral valve, which has two cusps,
separates the left atrium from the left
ventricle.
SEMILUNAR:
Two semilunar valves, each has three
cusps.
Pulmonic valve separates the right
ventricle from the pulmonary artery.
Aortic valve lies between the left
ventricle and the aorta.
THE TWO PHASES OF CARDIAC CYCLE
HEALTH ASSESSMENT LECTURE – WEEK 8.2 HEART AND CENTRAL VESSELS
THE SYSTOLE
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Ventricles contract.
Blood is ejected from the left
ventricle into the aorta and from the
right ventricle into the pulmonary
artery.
Mitral and tricuspid valves close
(first heart sound).
Pressure continues to rise.
Aortic and pulmonic valves open.
Blood ejected into arteries.
Pressure falls.
Aortic and pulmonic valves close
(second heart sound).
FOURTH HEART SOUND (S4)
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Occurs at end of diastole, at
presystole, when ventricle resistant
to filling.
Atria contract and push blood into
noncompliant ventricle.
This creates vibrations that are
heard as S4.
S4 occurs just before S1.
MURMURS
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THE DIASTOLE
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Mitral and tricuspid valves open.
Blood moves from atria to ventricles
(third heart sound).
Ventricles dilate, an energy-requiring
effort that draws blood into the
ventricles as the atria contract,
thereby moving blood from the atria
to the ventricles.
Atria contract as ventricles almost
filled.
Causes complete emptying of atria
(fourth heart sound).
EXTRA HEART SOUNDS
THIRD (3RD) HEART SOUND (S3)
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Normally diastole is silent event.
- However, in some conditions,
ventricular filling creates
vibrations that can be heard over
chest.
- S3 occurs when ventricles
resistant to filling during early
rapid filling phase
(protodiastole).
- Occurs immediately after S2
- when AV valves open and atrial
blood first pours into ventricles.
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Blood circulating through normal
cardiac chambers and valves
usually makes no noise.
However, some conditions
create turbulent blood flow and
collision currents.
These result in a murmur, much
like a pile of stones or a sharp
turn in a stream creates a noisy
water flow.
A murmur is a gentle, blowing,
swooshing sound that can be
heard on chest wall.
CHARACTERISTICS OF SOUND
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All heart sounds are described by.
1. Frequency or pitch:
described as high pitched or
low pitched.
2. Intensity or loudness: loud
or soft
3. Duration: very short for
heart sounds; silent periods
are longer
4. Timing: systole or diastole
HEALTH ASSESSMENT LECTURE – WEEK 8.2 HEART AND CENTRAL VESSELS