VELAMMAL EDUCATIONAL TRUST
Velammal Vidyalaya, Melayanambakkam
Name: S. SAISUDHA
Batch No:
Class: XII.C
Reg No:
CERTIFICATE
Certified that this is a bonafide Report of Project work
done by Mr./Ms S. SAISUDHA in ……………………..
during the year 2021-22
Teacher – in – charge
Submitted for the practical examination in ………………
at………………………… ……….held on…………………………
Internal Examiner
External Examiner
School Seal
ACKNOWLEDGEMENT
I am grateful to almighty for giving me the strength to complete
my project successfully with sustained efforts which many a time
did oscillate.
I am deeply indebted to Mr. /Ms…………………………… without
whose constructive feedback, this project would not have been a
success. The valuable advice and suggestions for the corrections,
modifications and improvement did enhance the quality of the
task.
I am obliged to Mr. /Ms…………………… our principal for
providing the best of facilities and environment to bring out
innovation and spirit of inquiry of venture.
I take special pleasure in acknowledging M. /Ms……………………….
for the willingness in providing us with necessary lab equipments.
I am grateful to my parents in completion of this task.
Last but not the least, I thank all my friends and batch mates
without their prompt support, my efforts would have one in vain.
INTRODUCTION
The human heart, the most vital organ in our body is a
blood pumping machine. It is created around a month
later after the formation of zygote and it beats ever since.
The day it stops marks the end of human life. The human
heart pumps blood throughout the body with the help of
the circulatory system, supplying oxygen and nutrients to
the tissues and removing carbon dioxide and other
wastes.
The heart is a muscular organ that serves to collect
deoxygenated blood from all parts of the body, carries it
to the lungs to be oxygenated and release carbon
dioxide. Then, it transports the oxygenated blood from
the lungs and distributes it to all the body parts.
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The heart pumps around 7,200 liters of blood in a day
throughout the body.
The heart is situated at the centre of the chest and
points slightly towards the left.
On average, the heart beats about 100,000 times a day,
i.e., around 3 billion beats in a lifetime.
An adult heart beats about 60 to 80 times per minute
and newborn baby’s heart beats faster than an adult
which is about 70 to 190 beats per minute.
ANATOMY
The Human heart is roughly the size of a large fist and
weighs between about 280 and 340 grams in men, and
between 230 and 280 grams in women.
(Source: Henry Gray's "Anatomy of the Human Body.”)The
human heart is located in the center of the chest - slightly
to the left of the sternum (breastbone). It sits between the
lungs and is encased in a double-walled sac called the
pericardium. The pericardium serves to protect the heart.
The fluid lubricates the heart during contractions and
movements of the lungs and diaphragm.
Layers of the Heart Walls
The heart wall consists of three layers enclosed in the
pericardium:
1. Epicardium - the outer layer of the wall of the heart
and is formed by the visceral layer of the serous
pericardium.
2. Myocardium - the muscular middle layer of the wall
of the heart and has excitable tissue and the
conducting system.
3. Endocardium.
Structure and Function
The heart is subdivided by septa into right and left
halves, and a constriction subdivides each half of the
organ into two cavities, the upper cavity being called the
atrium, the lower the ventricle.
 Therefore the heart itself is made up of 4 chambers, 2
atria and 2 ventricles.
 De-oxygenated blood returns to the right side of the
heart via the venous circulation.
 The oxygenated blood then travels back to the left
side of the heart into the left atria, then into the left
ventricle from where it is pumped into the aorta and
arterial circulation.
 The right ventricle pumps blood through the
pulmonary semi lunar valve into the pulmonary trunk
to be oxygenated in the lungs.
 Blood returning from the lungs drains into the left
atrium via the four pulmonary veins.
 The left atrium pumps blood through the bicuspid
(mitral) valve into the left ventricle
 The left ventricle pumps blood through the aortic
semi lunar valve into the ascending aorta to supply
the body.
 The coronary arteries run along the surface of the heart
and provide oxygen-rich blood to the heart muscle. A
web of nerve tissue also runs through the heart,
conducting the complex signals that govern
contraction and relaxation. Surrounding the heart is a
sac called the pericardium
BLOOD PRESSURES
 The pressure created in the arteries by the contraction
of the left ventricle is the systolic blood pressure.
 Once the left ventricle has fully contracted it begins to
relax and refill with blood from the left atria. The
pressure in the arteries falls whilst the ventricle
refills. This is the diastolic blood pressure.
 Normal systolic blood pressure is 120mmHg or
below.
 Normal diastolic pressure is 80mmHg or below.
 A normal blood pressure level is less than 120/80
mmHg. The “120” here refers to the systolic blood
pressure while the “80” refers to the diastolic b.p.
Heart Valves
The heart has four valves. All four valves of the heart
have a singular purpose: allowing forward flow of blood
but preventing backward flow. The outflow of each
chamber is guarded by a heart valve:
Atrioventricular valves between the atria and ventricles
1. tricuspid valve (R side of the heart)
2. mitral valve/bicuspid valve (left side of the heart)
Semi lunar valves which are located in the outflow tracts
of the ventricles
1. aortic valve (L side heart)
2. pulmonary valve (R side heart)
Heart Conduction System
 An electrical conduction system regulates the
pumping of the heart and timing of contraction of
various chambers. Heart muscle contracts in
response to the electrical stimulus received system
generate electrical impulses and conducts them
throughout the muscle of the heart, stimulating the
heart to contract and pump blood. Among the major
elements in the cardiac conduction system are the
sinus node, Atrioventricular node, and the autonomic
nervous system.
 The sinus node is the heart's natural pacemaker. The
sinus node is a cluster of cells situated in the upper
part of the wall of the right atrium. The electrical
impulses are generated there. (The sinus node is also
called the sinoatrial node.)
 The electrical signal generated by the sinus node
moves from cell to cell down through the heart until
it reaches the atrioventricular node (the AV node), a
cluster of cells situated in the center of the heart
between the atria and ventricles.
 The AV node serves as a gate that slows the
electrical current before the signal is permitted to
pass down through to the ventricles. This delay
ensures that the atria have a chance to fully contract
before the ventricles are stimulated. After passing
the AV node, the electrical current travels to the
ventricles along special fibers embedded in the walls
of the lower part of the heart.
 The autonomic nervous system (the same part of the
nervous system as controls the blood pressure)
controls the firing of the sinus node to trigger the
start of the cardiac cycle. The autonomic nervous
system can transmit a message quickly to the sinus
node so it in turn can increase the heart rate to twice
normal within only 3 to 5 seconds. This quick
response is important during exercise when the
heart has to increase its beating speed to keep up
with the body's increased demand for oxygen.
ECG AND ECHOCARDIOGRAM
 An electrocardiogram ( or ECG) and an
echocardiogram (echo) are tests that help find
problems with the heart muscle, valves, or rhythm.
 At every beat, the heart is depolarized to trigger its
contraction. This electrical activity is transmitted
throughout the body and can be picked up on the
skin. This is the principle behind the ECG. An ECG
machine records this activity via electrodes on the skin
and displays it graphically. An ECG involves attaching
10 electrical cables to the body: one to each limb and
six across the chest
 It prints out this information on ECG paper made up
of small squares 1mm squared.
 Each electrical stimulus takes the form of a wave and
so patterns emerge made up of a number of
connected waves. A standard ECG is printed at 25mm
per second or 25 small squares per second (see
above). In this way it is possible to calculate the
duration of individual waves.
 An ECG is a painless test that checks your heart’s
function without being invasive. It records the
electrical activity of the heart as wavy lines on a piece
of paper.
ECG can detect the following:
Irregular heartbeat
Damage to heart muscle and tissue
Changes in the thickness of the muscle in the heart
chamber walls
Chemical or electrolyte imbalances in the body
WAVES IN THE ECG
P wave
The P wave is a small deflection wave that represents atrial
depolarization.
PR interval
The PR interval is the time between the first deflection of
the P wave and the first deflection of the QRS complex.
QRS wave complex
The three waves of the QRS complex represent ventricular
depolarization.
ST segment
The ST segment, which is also known as the ST interval, is
the time between the end of the QRS complex and the
start of the T wave. It reflects the period of zero potential
between ventricular depolarization and repolarization.
T wave
T waves represent ventricular repolarization (atrial
repolarization is obscured by the large QRS complex)
 The picture given below is a representation of a
normal ECG. Any deviation from this graph could be
pointing to a condition in the heart.
An echo is an ultrasound of your heart. Ultrasounds use
high-frequency sound waves to take a picture of organs
inside the body. A wand-like device called a transducer
sends out sound waves. Then, the sound waves “echo”
back. Like an EKG, the test is painless and not invasive.
You may need an echo before, during, or after cancer
treatment to check for:
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Blood clots in the heart’s vessels
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Damage from previous heart attacks
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Any tumors
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Infection
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Problems with heart valves
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How well the heart pumps blood
Common heart conditions
Coronary heart disease
This is caused when the heart’s blood vessels - the
coronary arteries - become narrowed or blocked and can’t
supply enough blood to the heart.
It can lead to angina and/or a heart attack.
Angina
Angina is a pain or discomfort in your chest, arm, neck,
stomach or jaw that happens when the blood supply to
your heart becomes restricted because of your arteries
becoming narrowed. This clogging is called atheroma.
Angina is a symptom of coronary heart disease, not an
illness in itself.
Angina is heart’s way of telling it’s not getting enough
oxygen when the person is doing something strenuous or
feeling under stress.
Heart attack
A heart attack - also known as myocardial infarction or MI
- happens when the blood supply to part of the heart
muscle becomes completely blocked. This is most
commonly caused by a piece of fatty material breaking off
and a blood clot forms within a coronary artery. This can
cause damage to the part of the heart muscle which that
particular coronary artery was supplying.
Heart failure
If the heart’s pumping action can’t work effectively, the
heart muscle can’t meet the body’s demand for blood and
oxygen, and body develops various different symptoms,
like fatigue and shortness of breath. This is called heart
failure because of the failure of your heart to work
efficiently.
Key facts
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Cardiovascular diseases (CVDs) are the leading cause of
death globally.
An estimated 17.9 million people died from CVDs in
2019, representing 32% of all global deaths. Of these
deaths, 85% were due to heart attack and stroke.
Over three quarters of CVD deaths take place in lowand middle-income countries.
Out of the 17 million premature deaths (under the age
of 70) due to noncommunicable diseases in 2019, 38%
were caused by CVDs.
Most cardiovascular diseases can be prevented by
addressing behavioural risk factors such as tobacco use,
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unhealthy diet and obesity, physical inactivity and
harmful use of alcohol.
It is important to detect cardiovascular disease as early
as possible so that management with counselling and
medicines can begin.
BIBLIOGRAPHY:
https://www.who.int/news-room/factsheets/detail/cardiovascular-diseases-(cvds)
https://www.cancer.net/navigating-cancer-care/diagnosingcancer/tests-and-procedures/electrocardiogram-ekg-andechocardiogram
https://www.nottingham.ac.uk/nursing/practice/resources/cardiol
ogy/function/placement_of_leads.php
https://www.nhsinform.scot/illnesses-and-conditions/heart-andblood-vessels/conditions/common-heart-conditions