CIRCULATION:

FUNCTIONING OF HEART (10 MARK)

 Heart is a pumping organ.
 It receives blood from different parts of the body through the
veins .
 Veins open through inferior and superior vena cava and
pulmonary veins
 Right atrium receives deoxygenated blood.
 The left atrium receives oxygenated blood from the lungs.
 When the walls of the atria contract the right and the left atria
pump the blood into the right and left ventricle respectively.
 A pulmonary trunk arising from the right ventricle takes away
the blood to the lungs for oxygenation.
 The left ventricle gives to an aorta, from which oxygenated
blood is supplied to the coronary arteries and the systemic
circulation of the body.
 The blood flow between the right atrium and the right
ventricle is regulated by tricuspid valve.
 The bicuspid or mitral valve regulates the flow on the left
chambers of the heart.
 In the pulmonary trunk and the aorta, back flow of blood is
prevented by a set of semilunar valves.
ORIGIN AND CONDUCTION OF HEART BEAT:
 During pumping action of heart, the heart muscles
cause rhythmic contraction and relaxation of the heart
chambers in a specific sequence.
 The rhythmic, sequential functioning of the cardiac
chamber is maintained by sino-atrial node(SA node),
 Atrio-ventricular node(AV node),
 Bundle of His
 And purkinje fibres
 The SA node situated in the upper ,lateral wall of the
right atrium is a small, flattened strip of muscle fibre that
is 1.5cm into 3mm in size.
 The fibres of the SA node are closely associated with
the muscles of auricles.
 SA node is capable of generating action potential that
can travel throughout the auricles.
 The velocity of conduction is 0.3m/sec.

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  The excitation from the SA node stimulates the AV
node.
 The AV node in turn conducts the stimulus to bundle of
His and purkinji fibres.
 These myocardial fibres are found all over the wall of
the ventricles.
 In the conduction of stimulus through the AV node and
the fibrous system there is a delay in transmission.
 MYOCARDIAL INFRACTION (5 MARK)
•myocardial infraction is a coronary artery disease which
involves sudden death of the part of the heart muscle due to
blockage in the coronary artery.
• It may cause severe unremitting chest pain.
CAUSES:
• The coronary artery that supply the heart muscle with fresh
oxygenated blood become narrowed.
• This narrowing is usually due to an accumulation of droplets
of fatty substances, like cholesterol.
• the fibrous cover of the fat deposit sometimes rupture,
triggering the formation of a blood clot.
• If this blood clot blocks the artery, blood flow to an area of
the heart muscle stops, causing myocardial infraction and
leads to death of the tissue.

SYMPTOMS:

 Severe heavy crushing pain may spread up to the neck and

in to the arms especially the left arm.
 Sweating
 Shortness of breath
 Nausea and vomiting
 Anxiety sometimes accompanied by fear of dying.
 About one in five people experience no chest pain in
myocardial infraction.
 However, there may be fainting, sweating and pale skin.
 This pattern of symptom is known as ‘silent infraction’
 This type of infraction is common in people with diabetes
mellitus or those with elevated blood pressure.
RISK FACTORS:

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 a) Habitual cigarette smokers have a substantially increased
risk of dying from myocardial infraction.
b) High blood pressure is a major risk factor increases with
higher pressure
c) The risk of atherosclerosis and coronary artery disease
increases dramatically in those who are more than 30%
overweight.
d) A raised blood cholesterol level increases the risk. A high fat
diet is also a factor.
e) Physical inactivity is also a major factor.
ANGINA PECTORIS (5 MARK)
1) Angina is a term that describes a strangling or constrictive
pain
2) Angina has become synonymous with the heart disorder
called angina pectoris.
3) This heart disorder refers to chest pain caused by
insufficient supply of oxygen to the heart muscle ,usually a
result of poor blood supply
4) Angina pectoris usually occurs when the demand for
oxygen is increased during exercise and at the time of
stress.
5) The pain usually comes on suddenly
6) The pain ranges from a tight ache to intense crushing
agony
7) It lasts for 30 minutes or more and it is not relieved by rest
Causes:
a. Inadequate blood supply to heart due to coronary
artery disease such as atherosclerosis.
b. Severe attack of anaemia which reduces the oxygen
carrying capacity of blood.
c. Polycythemia (increased number of red blood
cells)which thickens the blood, causing it to slow its
flow through the heart muscle
d. Thyrotoxicosis (a disorder caused by excessive
secretion of thyroxin) can precipitate angina pectoris
by making the heart work harder and faster than its
blood supply will permit..

ANGIOGRAM (5 MARK)

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  Angiogram is a special contrast X-ray and can be used to
detect an abnormality in a blood vessel such as a narrowing
of a large diseased artery.
CORONARY ANGIOGRAM:
 Coronary angiogram is used to image the arteries that supply the
heart muscle with blood.
 Angiography can image narrowed or blocked coronary arteries,
which are not visible on a normal X-ray.
 A local anesthesia is injected and a fine flexible catheter is passed
within the femoral artery, through the aorta and into a coronary
artery.
 A contrast dye is injected through the catheter and a series of X-ray
taken.
 The procedure is painless.
CORONARY ANGIOPLASTY:
• Coronary angioplasty is an operation done to clear flow of
blood when the coronary arteries are narrowed or blocked by
fatty deposits with the help of a baloon catheter.
• Under local anesthesia, a guide wire is inserted through the
femoral artery in the groin and up into the affected coronary
artery.
• A baloon catheter is passed up the wire and the baloon is
inflated in the narrowed area to widen it.
• Sometimes, a metal tube called a stent is inserted.
• It keeps the artery open.
CORONARY BYPASS SURGERY:
 It is an operation to circumvent narrowed or blocked
coronary arteries by grafting additional blood vessels to transmit
blood flow.
 During this procedure the heart is temporarily stopped and
blood circulation and oxygenation is taken over by a heart lung
machine.
CARDIAC CYCLE (3&5 MARK)
 The sequential events occurring from the initiation of one
heart beat to the commencement of the next is called as one
cardiac cycle.
 In this cycle, the contraction phase is called systole.
 The relaxation phase is the diastole.
 A single heart beat comprises a systole and diastole in both
atria and ventricles.

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ATRIAL SYSTOLE:
o There is a continuous flow of blood into the right atrium
through superior and inferior vena cava and coronary sinus.
o Simultaneously the left atrium receives blood from 4
pulmonary veins.
o There is a passive movement of nearly 70% of the blood into
the ventricle.
o The remaining 30% is pumped into the ventricles by atrial
contraction.
VENTRICULAR FILLING:
• When the valves in between atria and ventricles open nearly
two-third of the ventricle is filled.
• Remaining space gets filled up by atrial constraction.
VENTRICULAR SYSTOLE:
 As the atrial systole ends, the action potential generated by the SA
nade reaches the AV node and rest of the fibrous system.
 It causes contraction of the ventricular wall.
 Thus ventricular pressure results.
 The very strong ventricular pressure pumps the blood into
respective arteries by causing the semilunar valves to open
VENTRICULAR DIASTOLE
 Soon after the blood leaves the ventricles there is a fall in the
ventricular pressure
 The semilunar valves close and the atrial valves open to begin the
next cycle.
HEART SOUND:
 The heart sound felt by a stethoscope is caused due to the closure
and opening of the valves
 The generation of sound is rhythmic
 The first sound is louder (lubb) and of longer duration(0.16 – 0.90
sec)
 It is due to closure of the atrioventricular valves at the ventricular
systole
 The second sound is of shorter duration (dubb)(0.10sec)
 It is caused at the end of the ventricular systole by the closure of
semilunar valve
 The heart beats at the rate of about 72-80 times per minute in
adults

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  The ventricular systole causes a wave of distension in the arteries
due to blood flow
 It is called as arterial pulse
 It can be felt on the wrist
 The pulse rate corresponds to rate of heart beat.

ATHEROSCLEROSIS (5 MARK)
• Atherosclerosis is narrowing of the arteries caused by plagues on
their inner linings
• These plagues are composed mainly of fats deposited from the
blood stream
• They disrupt the normal flow of blood through the affected artery
• Atherosclerosis encourages thrombus and embolus(fragment of
blood clot)
• Men are affected earlier than women are protected by natural
oestrogen hormones
Causes:
 Narrowing of the vessel is due to the development of raised patches
called plagues
 These plagues consists of athroma (fat and oil mixture),
 decaying muscle cells,
 fibrous tissue,
 clumps of blood platelets
 cholesterol and calcium(abnormal blood clot)
 in atherosclerosis the risk factors are
 cigarette smoking
 heredity
 aggressive personality
 hypertension
 male gender
 obesity
 physical inactivity
 diabetes mellitus
 severe effects of atherosclerosis are stroke (loss of blood supply to
brain)and heart attack (loss of blood supply to heart)
Heart block (3MARK)
 complete failure of the system that conducts electrical impulses
from the upper to the lower heart chamber is called the heart block

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  normally, electrical impulses pass from the sinu auricular node to
the atrio-ventricular node in the right atrium and then to the
ventricle
 in complete heart block, the impulses cannot reach the ventricle
 this defective production of the sinu atrial impulses and its
conduction in the heart is called heart block
Echo cardiography (3MARK)
 Echo cardiography is a technique that uses ultra sound waves to
image the interior of heart
 It is used to diagnose disorders of the heart and the heart valves
 The test is usually done by using an ultrasound transductor
(probe) placed on the skin of the chest directly over the heart
 In some cases a small probe is passed down the oesophagus
Rheumatic heart disease(RHD) (3 mark)
i. It is a common form of disease found throughout the world
ii. RHD is a crippling disease
iii. Rheumatic fever develops due to an infection usually of the throat,
caused by streptococcal bacteria
iv. The condition is caused by the immune system attacking the bodys
own tissues in response to the infection
v. The symptoms of rheumatic fever may include high fever, pain and
swelling in bone joints
ICCU-(Intensive coronary care unit ) (5 mark)
A. All major hospital in urban towns and cities have Intensive
coronary care unit to care for people in a critical or unstable
condition
B. They require continuous monitoring
C. This unit has a high variety of sophisticated equipments for
constantly monitoring the condition of the seriously ill patient
D. The patient may be connected to a ventilator to maintain breathing
E. Body fluids and blood sugar levels are maintained by intra venous
infusion of salts and glucose
F. Nutrients may also be supplied intravenously
G. Urine is collected through a catheter
H. Blood pressure is continuously monitored by an automatic
sphygmomanometer
I. Heart rate and rhythm are monitored by an ECG machine
J. Results are often relayed to a central monitoring unit

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 K. Monitors are fitted with alarms to alert the staff if there is any
dangerous variation from the normal range.
Blood Pressure (5mark):
• Blood pressure is the force exerted by the flow of blood against the
walls of the main arteries while flowing through them
• Blood pressure rises or falls as the heart responds to the varying
demands made by the body during different activities such as
exercise, stress and sleep
• Two types of pressure are measured
• Systolic (the highest) is the pressure created, by the ventricular
muscle and the elastic recoil of the aorta (main vessel leaving the
heart ) as the blood flows through it
• Diastole pressure (the lowest ) is recorded during relaxation of the
ventricles between beats
• It reflects the resistance of all the small arteries in the body and the
load against which the heart must work
• The pressure wave transmitted along the arteries with each heart
beat is felt as the pulse
• The blood pressure is measured using a sphygmomanometer
• A healthy adult has a blood pressure reading of about 120/80 mm
Hg-systolic and 80 mm Hg-diastolic)
• This often rises normally with age to about 130/90 at 60
• Abnormally high blood pressure is known as hyper tension
• Hyper tension is defined as the “systolic pressure equal to or greater
than 160 mm Hg and (or) the diastolic pressure equal to or greater
than 95 mm Hg”
• Abnormality low pressure is termed hypotension
Intensive of hypertension: (3&5 mark):
 Hypertension puts a strain on the heart and blood vessels
 Apart from increasing the risk of having a stroke or developing
heart failure or coronary artery disease, high blood pressure may
cause kidney damage and retinopathy (damage to the retina at the
retina at the back of the eye )
Causes:
 Hypertension is linked with obesity and in some people to a high
intake of salt, alcohol , smoking appears to aggravate the effects of
hypertension
Preventive measures:
• Alcohol consumption and smoking should be avoided

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 • obese persons should make an attempt to reduce weight through
restriction of food intake and try regular exercise
• The dietary intake of animal fat (milk, cream< cheese fatty meat
and eggs ) should be reduced
• A restricted intake of salt is recommended
Heart transplantation:
 It involves replacement of a person’s diseased or damaged heart by
a healthy human heart taken from a donor in whom the brain death
has been certified
 Heart transplantation in animals was first achieved bin 1959
 The first human heart transplant was performed by professor
Christian Bernard in south Africa in 1967
Limiting factors for heart transplantation:
1. problem of timing:
A heart transplant is possible only when a suitable donor heart is
available at right time
2. Problem of fall-back system:
if the heart is rejected (attacked by the body’s immune system)the
only hope for the patient is another transplant
2. Problem in certification of brain death:
3. the success of heart transplant lies in allowing doctors to certify brain
death while the heart was beating
4. heart is generatly removed for transplantation from a person certified
for brain death by doctors
pulse rate:
• The rhythmic expansion and contraction of an artery as blood is
forced through it (pumped by the heart ) is known as pulse
• The pulse can be described in terms of its rate (number of
expansion per minute) its rhythm
• Strength and
• Whether the blood vessel feels hard or soft
The blood:
 The blood is a fluid connective tissue
 It consists of liquid plasma and cells
 The plasma makes up 55% of the total volume and 45% of cells or
formed elements
 The total blood volume in human female is about 4-5 litres and 5-6
litres in males

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  PLASMA: the blood is a slightly alkaline fluid. it is straw coloured

Composition of plasma:
Components of plasma

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