CARDIOVASCULAR SYSTEM.pptx

CARDIOVASCULAR
SYSTEM
SUBMITTED TO: DR. DIVYAAGARWAL
(ASSISTANT PROFFESOR ,SoMAS,GDGU)
SUBMITTED BY: GARIMA SHARMA
(BPTSEM 8)
1
© 2023 Garima Sharma

TABLE OF CONTENTS
 INTRODUCTION TO CVS
 THE HEART
 HEART LAYERS
 HEART WALLS
 HEART SOUNDS
 CORONARY CIRCULATION
 GREAT VESSELS OF HEART
 CONDUCTION SYSTEM OF HEART
 CARDIAC CYCLE
 VASCULAR PATHWAYS
 TERMS RELATED TO BLOOD FLOW
 ELECTROCARDIOGRAM
 APPLIED ANATOMY OF CVS
 APPLIED PHYSIOLOGY OF CVS
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INTRODUCTION
 The cardiovascular system , also
called the circulatory system ,
maintains the distribution of
blood throughout the body and is
composed of the heart and the
blood vessels – arteries, capillaries
and veins.
 The circulatory system is
composed of two parts :
pulmonary circulation and
systemic circulation.
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HEART
 The heart is a muscular pump made up of
cardiac muscle fibres, could be considered
a muscle rather than an organ.
 It has four chambers : 2 upper atrium and
2 lower ventricles.
 The heart is located in the mediastinum in
the centre of the chest cavity; however ,it is
not exactly centered: more of the heart is
on the left side of the mediastinum than
the right.
 At about the size of the fist and shaped like
an upside down pear, the heart lies directly
behind the sternum.
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HEART LAYERS
The wall of the heart is quite thick and is composed of three layers.
1.Endocardium-innermost layer of the heart lining the heart chambers.
2.Myocardium- middle ,thick muscular layer of the heart.
3.Epicardium- outermost layer of the heart.
The heart is enclosed within a double-layered pleural sac, called pericardium.
The epicardium is the visceral pericardium and parietal pericardium , fluid between these layers
reduces friction as the heart beats.
HEART VALVES
Valves acts as restraining gates to control the direction of blood flow.
They allow blood to flow in forward direction only.
The 4 valves are:
1.Tricuspid valve- an AV valve which controls the opening between the right atrium and right
ventricle.
2.Mitral valve- aka bicuspid valve controls the opening between the left atrium and left ventricle.
3.Pulmonary valve- a semilunar valve which is located between right ventricle and pulmonary
artery.
4.Aortic valve- semilunar valve which is located between left ventricle and aorta.
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HEART SOUNDS
 Heart sounds are the noises generated by the heart during cardiac
cycle ,specifically when cardiac valves snap shut.
a) S1: the first heart sound, dull and prolonged ( often described as
LUB)
b) S2: the second heart sound, sharp and short( often described as
DUB)
c) S3: the third heart sound, occasionally heard ,weak & rumbling (
often described as LUB-DUB-TA)
d) S4: the fourth heart sound, weak and rumbling( often described as
TA- LUB-DUB)
 MURMURS: abnormal or ectopic heart sounds, occurs when there is
any vulvar abnormality.
four types ,viz : 1. aortic regurgitation
2. aortic stenosis
3. mitral regurgitation
4. mitral stenosis 7

CORONARY CIRCULATION
 Coronary circulation is circulation of blood in the arteries
and veins that supply myocardium.
 It consists of ;
1.ARTERIAL SUPPLY
2.VENOUS DRAINAGE
3.LYMPHATIC DRAINAGE
ARTERIAL SUPPLY: 2 coronary arteries branches off from
the aorta near the point where the point where the aorta
and the left ventricle meet.
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 A) RIGHT CORONARY ARTERY: emerges from surface of heart between pulmonary
trunk and right ventricle and terminates by anastomosing with left coronary
artery.
 It supplies right atrium ,ventricles, posterior part of IV septum and whole of the
conduction system of heart except a part of left branch of AV bundle.
 B) LEFT CORONARY ARTERY: arises from posterior aortic sinus and terminates
by anastomosing with right coronary artery.
 It supplies left atrium, ventricles, anterior part of interventricular septum, part of
left AV bundles.
 C) COLLATERAL CIRCULATION: cardiac anastomosis, extracardiac anastomosis,
vasa vasorum, internal thoracic, the bronchial arteries, phrenic arteries.
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 VENOUS DRAINAGE: it occurs by three ways
 A) CORONARY SINUS- Largest vein of the heart situates in the left posterior coronary
sulcus. It has six branches( great cardiac vein, middle cardiac vein, small cardiac vein,
posterior vein of left ventricle , oblique vein of left ventricle ,the right marginal vein.
 B) ANTERIOR CARDIAC VEINS- 3-4 small veins run on anterior wall of the right ventricle,
open directly into the right atrium.
 C) VENAE CORDIS MINIMAE- numerous small veins present in all 4 chambers of the heart
which opens directly into the cavities.
The thebesian network is considered as an alternative pathway for venous drainage of
the myocardium.
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 LYMPHATIC DRAINAGE : cardiac lymphatic vessels form subendocardial, myocardial and
sub epicardial plexus that play essential roles in myocardial fluid and immune cell
homeostasis.
 INNERVATION: innervation of cardiac cycle is myogenic, originating in SA node.
a) sympathetic cardiac innervation: increases conduction speed and heart rate.
b)parasympathetic cardiac innervation: slows HR and constricts coronary arteries.
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GREAT VESSELS OF HEART
 The great vessels of the heart are major blood vessels that connect directly to your heart.
These vessels participate in pulmonary and systemic circulation.
 The great vessels include : AORTA, PULMONARY TRUNK, PULMONARY VEINS, SUPERIOR VENA
CAVA AND INFERIOR VENA CAVA.

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CONDUCTION SYSTEMOF HEART
 The cardiac conduction system is a collection of nodes and specialised conduction cells that
initiate and co-ordinate contraction of the heart muscle. It consists of:
1.Sinoatrial node: it creates an excitation signal (an action potential) .
2.Atrioventricular node: Upon reaching the AV node, impulse delays by 120ms.
3.Atrioventricular bundle (bundle of His): conducted down to interventricular septum.
4.Purkinje fibres: spread the wave impulses along the ventricles, causing them to contract.
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CARDIAC CYCLE
 A cardiac cycle is the sequence of mechanical and electrical events that
occurs with every heartbeat. At rest, the heart pumps around 5L of blod
around the body every minute.
 A healthy heart that beats 70-75 times a minute takes about 0.8 seconds
to complete each cardiac cycle.
 The cycle begins with JOINT DIASTOLE with both chambers (atria and
ventricles) relaxed.
 Towards the end of the ventricular diastole, the atria on both sides
contract , pushing more blood into both the ventricles with pressure.
 Next ventricular systole begins , closing the mitral and tricuspid valves
and the blood is ejected from the right and left sides into the pulmonary
artery and aorta respectively. By this time, the atria are in Atrial diastole
and relaxed.
 As ventricular diastole begins again, the semilunar valves at the mouth of
the pulmonary artery and the aorta close, preventing backflow and
ensuring that the ventricles receive blood only from the atria before the
next cycle.
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THE VASCULAR PATHWAYS
 The cardiovascular has two circuits : PULMONARY & SYSTEMIC ,hence it is called
double circulation.
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TERMS RELATED TO BLOOD FLOW
 HEART RATE: the number of times the heart beats each minute. (normal
HR: 60-100bpm)
 STROKE VOLUME: the vol. of blood pumped out of the left ventricle of
the heart during each cycle.
 CARDIAC OUTPUT: amount of blood pumped by heart per min.( normal
value-5-6 L).
 BLOOD PRESSURE: pressure of circulating blood against the walls of
blood vessels.
2 types of blood pressure
a) Systolic BP: pressure of blood against the wall of blood vessels
when heart is contracting.
b) Diastolic BP: pressure of blood again the wall of blood vessels
when heart is relaxed.
overall blood pressure is measures as SYSTOLIC BP/ DIASTOLIC BP
the normal value of blood pressure is 120/80 mm of Hg
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ELECTROCARDIOGRAM
 The ECG is a representation of the electrical events of the cardiac cycle.
 ECG can identifies arrhythmias, myocardial ischaemia, pericarditis, hypertrophy,electrolyte
disturbances, drug toxicity.
 What do the segments of the ECG represent?
 P-wave: Atrial contraction
 PR interval: Represents the time taken for excitation to spread from the sino-atrial (SA)
node across the atrium and down to the ventricular muscle via the bundle of His.
 QRS: Ventricular contraction
 ST segment: Ventricular relaxation
 T-wave: Ventricular repolarisation

 Normal duration of ECG segments:
 PR interval: 0.12 – 0.2 secs (3-5 small squares)
 QRS: <0.12 secs (3 small squares)
 QTc: 0.38 – 0.42 secs

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APPLIED ANATOMY OF CVS
 DEXTROCARDIA: a condition in which heart lies on the right side of the thorax instead of
left.
 COR TRIATRIATUM (sinistrum): a rare cardiac anomaly in which the left/right atrium is
divided into proximal and distal chambers by a fibromuscular septum.
 ATRIAL SEPTAL DEFECT: atrial septal defect involves the AV septum and represents a
malformation of the endocardial cushions; it is almost invariably associated with mitral
and tricuspid abnormalities
 VENTRICULAR SEPTAL DEFECT: a congenital defect where there is a hole in the wall
separating two ventricles.
 TERTALOGY OF FALLOT: combination of 4 congenital defects ; a) pulmonary stenosis b)
overriding aorta c) ventricular septal defect d) right ventricular hypertrophy
 TRUNCUS ARTERIOSUS: a condition in which a single blood vessel comes out of the
ventricle, instead of two(pulmonary artery and aorta).
 TRANSPOSITION OF GREAT VESSELS: a defect in which two Major arteries that carry
blood away from the heart- the aorta and the pulmonary artery are switched(
transposed)
 PATENT DUCTUS AETERIOSUS: a condition in which PDA fails to close after birth.
 COARCTATION OF AORTA: a congenital defect causing narrowing of aorta. 24

APPLIED PHYSIOLOGY OF CVS
 CARDIAC ARREST: sudden loss of all heart activity due to an irregular heart rhythm.
Hence heart stops beating ,person becomes unconscious.
 HEART FAILURE: it occurs when the heart muscles does not pump enough blood to
fulfill the demand of body.
 HEART ATTACK: it occurs when coronary circulation is severely reduced or blocked
causing myocardial necrosis, henceforth called myocardial infarction.
 ARTERIOSCLEROSIS: the blood vessels lose their elasticity and flexibility & become stiff.
 ATHEROSCLEROSIS: it is a condition where there is a buildup of fats and cholesterol
(plaque) in and on the artery walls, which can cause narrowing of space, blocking blood
flow.
 HYPERTENSION: a chronic condition of persistently raised BP .( greater than 140/90
mm of Hg)
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