The cardiovascular system consists of the heart and blood vessels. The heart has four chambers and pumps blood through the blood vessels. It is surrounded by layers including the outer fibrous pericardium, middle myocardial muscle layer, and inner endocardial lining. Blood flows from the heart through arteries and arterioles, into capillaries where gas exchange occurs, and returns to the heart through veins and venules. Valves in the heart and vessels ensure one-way blood flow. The cardiovascular system circulates blood to supply the body with oxygen and nutrients and remove waste.

1. CARDIOVASCULAR SYSTEM
BY
SONI KUMARI SHAH

2. Cardiovascular System
The cardiovascular (cardio – heart, vascular – blood vessels)
system is divided for descriptive purposes into two main parts:
The heart, whose pumping action ensures constant circulation of
the blood
The blood vessels, which form a lengthy network through which
the blood flows.

3. Organs Of Cardiovascular System
Blood: It is a fluid connective tissue.
Blood vessel: It is the channel in which blood is flowing.
Heart: It is a muscular blood pumping organ.

4. Blood Vessels
Blood vessels vary in structure, size
and function, and there are several
types:
Arteries
Arterioles
Capillaries
Venules
Veins
arterioles
venules

5. Types of Blood vessels

6. Arteries And Arterioles
These blood vessels transport blood away from the heart.
They vary considerably in size and their walls consist of three layers of
tissue:
tunica adventitia or outer layer of fibrous tissue
tunica media or middle layer of smooth muscle and elastic tissue
tunica intima or inner lining of squamous epithelium called
endothelium.

7. Arteries And Arterioles
The amount of muscular and elastic tissue varies
in the arteries depending upon their size and
function.
In the large arteries, including the aorta,
sometimes called elastic arteries, the tunica media
contains more elastic tissue and less smooth
muscle.
This allows the vessel wall to stretch, absorbing
the pressure wave generated by the heart as it
beats.

8. Arteries And Arterioles
These proportions gradually change as the arteries branch many times
and become smaller until in the arterioles (the smallest arteries) the
tunica media consists almost entirely of smooth muscle.
This enables their diameter to be precisely controlled, which regulates
the pressure within them.
Arteries have thicker walls than veins to withstand the high pressure of
arterial blood.

9. Anastomoses And End-arteries
Anastomoses are arteries that form a link between main arteries
supplying an area, e.g. the arterial supply to the palms of the hand and
soles of the feet, the brain, the joints and, to a limited extent, the heart
muscle.
If one artery supplying the area is occluded, anastomotic arteries
provide a collateral circulation.
This is most likely to provide an adequate blood supply when the
occlusion occurs gradually, giving the anastomotic arteries time to
dilate.

10. Anastomoses And End-arteries
An end-artery is an artery that is the sole source of blood to a tissue,
e.g. the branches from the circulus arteriosus (circle of Willis) in the
brain or the central artery to the retina of the eye.
When an end-artery is occluded the tissues it supplies die because
there is no alternative blood supply.

11. Capillaries And Sinusoids
The smallest arterioles break up into a number of minute vessels
called capillaries.
Capillary walls consist of a single layer of endothelial cells sitting on a
very thin basement membrane, through which water and other small
molecules can pass.
Blood cells and large molecules such as plasma proteins do not
normally pass through capillary walls.
The capillaries form a vast network of tiny vessels that link the smallest
arterioles to the smallest venules.

12. Capillaries And Sinusoids
In certain places, including the liver and bone marrow, the capillaries
are significantly wider and leakier than normal.
These capillaries are called sinusoids and because their walls are
incomplete and their lumen is much larger than usual, blood flows
through them more slowly under less pressure and can come directly
into contact with the cells outside the sinusoid wall.
This allows much faster exchange of substances between the blood
and the tissues.

13. Capillary Refill Time
When an area of skin is pressed firmly with a finger, it turns white
(blanches) because the blood in the capillaries under the finger has been
squeezed out.
Normally it should take less than two seconds for the capillaries to refill
once the finger is removed, and for the skin to turn pink again.
Although the test may produce unreliable results, particularly in adults,
its use in children can be useful and a prolonged capillary refill time
suggests poor perfusion or dehydration.

14. Veins And Venules
Veins return blood at low pressure to the heart.
The walls of the veins are thinner than arteries but have the same
three layers of tissue .
They are thinner because there is less muscle and elastic tissue in
the tunica media, as veins carry blood at a lower pressure than
arteries.
When cut, the veins collapse while the thicker-walled arteries
remain open. When an artery is cut blood spurts at high pressure
while a slower, steady flow of blood escapes from a vein.

15. Veins And Venules
Some veins possess valves, which prevent backflow of blood, ensuring that it flows
towards the heart.
They are formed by a fold of tunica intima and strengthened by connective tissue.
The cusps are semilunar in shape with the concavity towards the heart.
Valves are abundant in the veins of the limbs.
They are absent in very small and very large veins in the thorax and abdomen.
Valves are assisted in maintaining one-way flow by skeletal muscles surrounding the
veins.

16. Veins And Venules
The smallest veins are called venules.
Veins are called capacitance vessels because they are distensible,
and therefore have the capacity to hold a large proportion of the
body’s blood.

17. Types Of Blood Vessels On The Basis Of Function
Conducting vessels
Distributing vessels
Resistance vessels
Exchanging vessels
Capacitance vessels

18. Blood Supply Of Blood Vessels
The outer layers of tissue of thick-walled blood vessels receive
their blood supply via a network of blood vessels called the vasa
vasorum.
Thin-walled vessels and the endothelium of the others receive
oxygen and nutrients by diffusion from the blood passing through
them.

19. Blood Vessel Diameter And Blood Flow
Resistance to flow of fluids along a tube is determined by three factors: the
diameter of the tube; the length of the tube; and the viscosity of the fluid.
The most important factor determining how easily the blood flows through blood
vessels is the diameter of the resistance vessels (the peripheral resistance).
The length of the vessels and viscosity of blood also contribute to peripheral
resistance, but in health these are constant and are therefore not significant
determinants of changes in blood flow.
Peripheral resistance is a major factor in blood pressure regulation. Constant
adjustment of blood vessel diameter helps to regulate peripheral resistance and
systemic blood pressure.

20. Differences Between Artery And Vein
SN Arteries Vein
1 Arteries carry oxygenated blood,
away from heart except pulmonary
artery
Veins carry deoxygenated blood,
towards the heart except pulmonary
vein
2 These are mostly deeply situated in
the body.
These are superficial and deep in
location.
3 They have thick wall. They have thin wall.
4 They pass narrow lumen. They pass wide lumen.
5 They are reddish in color. They are bluish in color.
6 Arteries blood pressure is high. Veins blood pressure is low.
7 High elasticity. Low elasticity.
8 Internal valves are absent. Internal valves are present.

21. Thrombus and Embolus
A blood clot formed within the heart or blood vessels from the
constitute of blood, causing obstruction of blood vessel is known as
thrombus.
Embolus or embolism is a mass of undissolved matter present in the
blood vessel or lymphatic vessel causing obstruction, which is brought
there by blood or lymph and it may be solid, liquid or gaseous.

22. Heart
The heart is a roughly cone-shaped
hollow muscular organ.
It is about 10 cm long and is about
the size of the owner’s fist.
It weighs about 225 g in women and
is heavier in men (about 310 g).

23. Position of heart
The heart lies in the thoracic cavity in the
mediastinum (the space between the lungs).
Vertebral level: 5th to 8th thoracic vertebrae
It lies obliquely, a little more to the left than
the right, and presents a base above, and an
apex below.
The apex is about 9 cm to the left of the
midline at the level of the 5th intercostal
space, i.e. a little below the nipple and
slightly nearer the midline.
The base extends to the level of the 2nd rib.

24. Apex Beat
The apex is the tip or summit of the heart and the apex beat is the impact of
the organ against the chest wall during systole.
The normal apex beat can be palpated in the pericardium on left 5th intercostal
space.
In children apex beat occurs 4th intercostal space medial to nipple.
Importance Of Apex Beat
Measurement of heart rate
Position of heart
Diagnosis of different heart diseases.

25. External Structure Of Heart
Surfaces of heart
Anterior surface
Inferior surface
Posterior surface
Right and left pulmonary surface
The coronary sulcus circles the heart, separating atria from the ventricle.
The anterior and posterior interventricular sulcus separates the two ventricles.

26. Organs associated with the heart
Inferiorly – the apex rests on the central
tendon of the diaphragm
Superiorly – the great blood vessels, i.e. the
aorta, superior vena cava, pulmonary artery
and pulmonary veins
Posteriorly – the oesophagus, trachea, left
and right bronchus, descending aorta, inferior
vena cava and thoracic vertebrae
Laterally – the lungs – the left lung overlaps
the left side of the heart
Anteriorly – the sternum, ribs and intercostal
muscles.

27. Structure Of Heart
The heart wall
The heart wall is composed of
three layers of tissue:
Pericardium
Myocardium and
Endocardium.

28. Pericardium
The pericardium is the outermost layer and
is made up of two sacs.
The outer sac (the fibrous pericardium)
consists of fibrous tissue and the inner (the
serous pericardium) of a continuous double
layer of serous membrane.
The outer layer of the serous pericardium,
the parietal pericardium, lines the fibrous
pericardium. The inner layer, the visceral
pericardium, which is continuous with the
parietal pericardium, is adherent to the
heart muscle.

29. Pericardial Fluid
The serous membrane consists of flattened epithelial cells. It secretes
serous fluid, called pericardial fluid, into the space between the visceral
and parietal layers, which allows smooth movement between them when
the heart beats.

30. Myocardium
The myocardium is composed of specialized
cardiac muscle found only in the heart.
It is striated, like skeletal muscle, but is not
under voluntary control.
Each fiber (cell) has a nucleus and one or
more branches.

31. Myocardium
The ends of the cells and their branches are in very close contact with
the ends and branches of adjacent cells.
Microscopically these ‘joints’, or intercalated discs, are thicker, darker
lines than the striations.
The myocardium is thickest at the apex and thins out towards the base

32. Endocardium
This lines the chambers and valves of the heart.
It is a thin, smooth membrane to ensure smooth flow of blood
through the heart.
It consists of flattened epithelial cells, and it is continuous with the
endothelium lining the blood vessels.

33. Interior Of The Heart
Consists of
Chambers Of Heart(four)
Right Atrium
Right Ventricle
Left Atrium
Left Ventricle
Valves Of Heart
Atrioventricular Valve
Bicuspid Valve
Tricuspid Valve
Semi Lunar Valve
Pulmonary Valve
Aortic Valve

34. Chambers Of The Heart
Heart is made up of four chambers. Upper two chambers are known as
atrium and lower two chambers are known as ventricles.
Right Atrium
The right atrium serves as the receiving chamber for blood returning to
the heart from the systemic circulation.
The two major systemic veins, the superior and inferior venae cava, and
the large coronary vein called the coronary sinus that drains the heart
myocardium empty into the right atrium.

35. Right Atrium
The superior vena cava drains blood from regions superior to the
diaphragm: the head, neck, upper limbs, and the thoracic region.
The inferior vena cava drains blood from areas inferior to the
diaphragm: the lower limbs and abdominopelvic region of the body.
The atria receive venous blood on a nearly continuous basis, preventing
venous flow from stopping while the ventricles are contracting. The
opening between the atrium and ventricle is guarded by the tricuspid
valve.

36. Right Ventricle
The right ventricle receives blood from the right atrium through the tricuspid
valve.
Each flap of the valve is attached to strong strands of connective tissue, the
chordae tendineae, They connect each of the flaps to a papillary muscle.
There are three papillary muscles.
When the right ventricle contracts, it ejects blood into the pulmonary trunk,
which branches into the left and right pulmonary arteries that carry it to each
lung.
At the base of the pulmonary trunk is the pulmonary semilunar valve that
prevents backflow from the pulmonary trunk.

37. Left Atrium
After exchange of gases in the pulmonary capillaries, blood returns to
the left atrium high in oxygen via one of the four pulmonary veins.
The opening between the left atrium and ventricle is guarded by the
mitral valve.

38. Left Ventricle
The muscular layer is much thicker in the left ventricle compared to
the right.
The mitral valve is connected to papillary muscles via chordae
tendineae.
There are two papillary muscles.
The left ventricle is the major pumping chamber for the systemic
circuit; it ejects blood into the aorta through the aortic semilunar
valve.

39. Valves Of Heart
Atrioventricular Valve:
Right atrioventricular valve: It lies
between right atrium and right ventricle. It
is also known as tricuspid valve. It has
three flaps.
Left atrioventricular valve: It lies between
left atrium and left ventricle. It is also
known as bicuspid valve or mitral valve. It
has two flaps.

40. Valves Of Heart
Semilunar Valve: These are the two types
of valve found on the main branch of
arteries
Pulmonary valve: It lies in the opening of
pulmonary trunk.
Aortic valve: It lies in the opening of
aorta.

41. Valves Of Heart

42. Interior Of The Heart
The heart is divided into a right and left side by the septum.
Each side is divided by an atrioventricular valve into the upper atrium
and the ventricle below.
The right atrioventricular valve (tricuspid valve) has three flaps or
cusps and the left atrioventricular valve (mitral valve) has two cusps.
Flow of blood in the heart is one way; blood enters the heart via the
atria and passes into the ventricles below.

43. Interior Of The Heart
The valves between the atria and ventricles open and close passively
according to changes in pressure in the chambers.
They open when the pressure in the atria is greater than that in the
ventricles.
During ventricular systole (contraction) the pressure in the ventricles
rises above that in the atria and the valves snap shut, preventing
backward flow of blood prevented from opening upwards into the atria
by tendinous cords, called chordae tendineae attached to papillary
muscles.

45. Flow Of Blood Through The Heart
The two largest veins of the body, the superior
and inferior venae cava, empty their contents
into the right atrium.
 This blood passes via the right atrioventricular
valve into the right ventricle, and from there is
pumped into the pulmonary artery or trunk
(the only artery in the body which carries
deoxygenated blood). The opening of the
pulmonary artery is guarded by the pulmonary
valve, formed by three semilunar cusps. This
valve prevents the backflow of blood into the
right ventricle when the ventricular muscle
relaxes.

46. Flow Of Blood Through The Heart
After leaving the heart the pulmonary trunk
divides into left and right pulmonary arteries,
which carry the venous blood to the lungs where
exchange of gases takes place: carbon dioxide is
excreted and oxygen is absorbed.
Two pulmonary veins from each lung carry
oxygenated blood back to the left atrium.
Blood then passes through the left
atrioventricular valve into the left ventricle, and
from there it is pumped into the aorta, the first
artery of the general circulation. The opening of
the aorta is guarded by the aortic valve, formed
by three semilunar cusps

47. Blood Supply To The Heart (The Coronary
Circulation)
Arterial Supply
The heart is supplied with arterial blood by the right
and left coronary arteries, which branch from the
aorta immediately distal to the aortic Valve.
The coronary arteries receive about 5% of the blood
pumped from the heart, This large blood supply, of
which a large proportion goes to the left ventricle,
highlights the importance of the heart to body
function.
The coronary arteries traverse the heart, eventually
forming a vast network of capillaries.

48. Branches Of Right Coronary Artery
Anterior ventricular branch
Marginal branch
Posterior ventricular branch
Posterior interventricular artery
Atrial branch
Branches Of Left Coronary Artery
Anterior interventricular branch
Circumflex artery
Left marginal branch
Anterior ventricular and posterior ventricular branch
Atrial branches

49. Venous Drainage
Most of the venous blood is collected
into a number of cardiac veins that join
to form the coronary sinus, which opens
into the right atrium.
The remainder passes directly into the
heart chambers through little venous
channels.

50. Tributaries Of Coronary Sinus
Great cardiac vein
Middle cardiac vein
Small cardiac vein
Left posterior ventricular vein
Left marginal vein
Anterior cardiac vein

51. Nerve Supply Of Heart
Sympathetic supply
From cardiac plexus formed from cervical and upper thoracic portion of
sympathetic trunk.
It increases the conductivity and contractility of heart muscles.
Sympathetic nerves supply the SA and AV nodes and the myocardium of atria
and ventricles
stimulation increases the rate and force of the heartbeat.

52. Nerve Supply Of Heart
Parasympathetic supply
From vagus nerve
It decreases conductivity and contractility.
Supplies SA and AV nodes and atrial muscle.
Vagal stimulation reduces the rate at which impulses are produced, decreasing
the rate and force of the heartbeat.

53. Conducting System Of The Heart
The heart possesses the property of auto rhythmicity, which means it
generates its own electrical impulses and beats independently of nervous
or hormonal control, i.e. it is not reliant on external mechanisms to
initiate each heartbeat.
Small group of specialized neuromuscular cells in the myocardium initiate
and conduct impulses causing a co-ordinate and synchronized contraction
of heart muscles.

54. Components Of Conducting System
1. SA (Sinoatrial) node
2. AV(Atrioventricular) node
3. Bundle of His or AV Bundle
4. Subendocardial plexus of purkinje fibers

55. Sinoatrial node (SA node)
This small mass of specialized cells lies in the wall of the right atrium near the
opening of the superior vena cava.
The sinoatrial cells generate these regular impulses because they are
electrically unstable.
This instability leads them to discharge (depolarize) regularly, usually between
60 and 80 times a minute.

56. Sinoatrial node (SA node)
This depolarization is followed by recovery (repolarization), but almost
immediately their instability leads them to discharge again, setting the
heart rate.
Because the SA node discharges faster than any other part of the heart, it
normally sets the heart rate and is called the pacemaker of the heart.
Firing of the SA node triggers atrial contraction.

57. Atrioventricular node (AV node)
This small mass of neuromuscular tissue is situated in the wall of the atrial
septum near the atrioventricular valves.
Normally, the AV node merely transmits the electrical signals from the
atria into the ventricles.
There is a delay here; the electrical signal takes 0.1 of a second to pass
through into the ventricles. This allows the atria to finish contracting before
the ventricles start.

58. Atrioventricular node (AV node)
The AV node also has a secondary pacemaker function and takes over this
role if there is a problem with the SA node itself, or with the transmission
of impulses from the atria.
Its intrinsic firing rate, however, is slower than that set by the SA node (40–
60 beats per minute).

59. Atrioventricular bundle (AV bundle or bundle of His) and Purkinje Fibers
This mass of specialized fibers originates from the AV node.
The AV bundle crosses the fibrous ring that separates atria and ventricles then,
at the upper end of the ventricular septum, it divides into right and left bundle
branches.
Within the ventricular myocardium the branches break up into fine fibers, called
the Purkinje fibers.
The AV bundle, bundle branches and Purkinje fibers transmit electrical impulses
from the AV node to the apex of the myocardium where the wave of ventricular
contraction begins, then sweeps upwards and outwards, pumping blood into
the pulmonary artery and the aorta.

60. Mechanism Of Action Of Conducting System
The impulses from SA node are conducted to
AV node by three types of internodal fibers.
All these fibers converge towards the AV
node and interdigitate with fibers of AV
node, the bundle of His arises and this
divides into right and left branches.
These branches run on either side of
interventricular septum and gives off
Purkinje fibers which spread all over the
ventricular myocardium.

61. The Cardiac Cycle
At rest, the healthy adult heart is likely to beat at a rate of 60–80 beats per minute
(bpm). During each heartbeat, or cardiac cycle, the heart contracts (systole) and then
relaxes (diastole).
The rhythmic contraction and relaxation of heart chambers in cyclic pattern is called
cardiac cycle.
During each heart beat or cardiac cycle the heart contract and then relax.
The period of contraction is called systole and relaxing period is called diastole.
The complete cardiac cycle is of 0.8 seconds.

62. Stages Of The Cardiac Cycle
Taking 74 bpm as an example, each
cycle lasts about 0.8 of a second and
consists of:
Atrial Systole – contraction of
the atria
Ventricular Systole –
contraction of the ventricles
Complete Cardiac Diastole –
relaxation of the atria and ventricles.

63. Atrial Systole
Simultaneous contraction of both atria.
Opens AV valves( bicuspid and tricuspid valves).
Blood flows within the ventricles of respective sides.
No heart sound is produced.
Completes within 0.1 sec.

64. Ventricular Systole
Simultaneous contraction of both ventricles.
Bicuspid and Tricuspid valves get closed so that first heart sound
(LUBB) is produced
Blood is forced into pulmonary artery and aorta.
It completes within 0.3 seconds.

65. Complete Cardiac Diastole
Relaxation of both atria and ventricles together.
Both atria gets filled with blood.
Pulmonary and aortic valves get closed to prevent backflow of
blood so that second heart sound(DUBB) is produced.
It completes within 0.4 seconds.

66. The Cardiac Circle

67. Control Of Cardiac Cycle
Intrinsic Control
The heart beat originates and is controlled by SA node present
within the heart. SA node rhythmically generates the impulses
throughout the life.
Extrinsic Control
Though cardiac impulse is self generated and controlled, it can be
changed extrinsically(outside the heart) by hormones and neural
impulses.

68. Extrinsic Control
Hormonal Control
Various hormones like thyroxin, insulin, adrenaline, nor adrenaline and
sex hormones directly act on the SA node stimulating and inhibiting the
cardiac impulse.
Neural Impulse
The cardiovascular area is situated in the medulla. Heart is under control
of autonomic nervous system. ANS have two group of nerve fibers:
sympathetic and parasympathetic. Vagus nerve from parasympathetic
nervous system slows the heart rate while sympathetic nerves accelerate
the heart beat.

69. Heart Sound
There are four heart sounds, each corresponding to a particular event in the
cardiac cycle. The first two are most easily distinguished, and sound through the
stethoscope like ‘lub dup’.
The first sound (S1), ‘lub’, is fairly loud and is due to the closure of the
atrioventricular valves. This corresponds with the start of ventricular systole.
The second sound(S2), ‘dup’, is softer and is due to the closure of the aortic and
pulmonary valves. This corresponds with ventricular diastole.
In both cases, as the valves close, the openings within the atrioventricular
septum guarded by the valves will become reduced, and blood flow through the
opening will become more turbulent until the valves are fully closed.

70. Heart Sound
There is a third heart sound, S3, but it is rarely heard in healthy
individuals. It may be the sound of blood flowing into the atria, or blood
sloshing back and forth in the ventricle, or even tensing of the chordae
tendineae. S3 may be heard in youth, some athletes, and pregnant
women. If the sound is heard later in life, it may indicate congestive
heart failure, warranting further tests.
The fourth heart sound, S4, results from the contraction of the atria
pushing blood into a stiff or hypertrophic ventricle, indicating failure of
the left ventricle. S4 occurs prior to S1

71. Heart Murmur
The term murmur is used to describe an unusual sound coming from the
heart that is caused by the turbulent flow of blood.
Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the
most difficult sound to detect, and the least serious. The most severe is 6.
Phonocardiograms or auscultograms can be used to record both normal and
abnormal sounds using specialized electronic stethoscopes.

72. Heart Murmur
During auscultation, it is common practice for the clinician to ask the patient
to breathe deeply.
This procedure not only allows for listening to airflow, but it may also amplify
heart murmurs.
Inhalation increases blood flow into the right side of the heart and may
increase the amplitude of right-sided heart murmurs.
Expiration partially restricts blood flow into the left side of the heart and may
amplify left-sided heart murmurs.

74. Proper Placement Of The Bell Of The Stethoscope To Facilitate
Auscultation.

75. Electrocardiogram (ECG)
The body tissues and fluids conduct electricity
well, so the electrical activity in the heart can be
recorded on the skin surface using electrodes
positioned on the limbs and/or the chest.
This recording, called an electrocardiogram (ECG)
shows the spread of the electrical signal
generated by the SA node as it travels through the
atria, the AV node and the ventricles.
The normal ECG tracing shows five waves which,
by convention, have been named P, Q, R, S and T.

76. Electrocardiogram (ECG)
The P wave arises when the impulse from the SA
node sweeps over the atria (atrial depolarization).
The QRS complex represents the very rapid
spread of the impulse from the AV node through
the AV bundle and the Purkinje fibers and the
electrical activity of the ventricular muscle
(ventricular depolarization).
The T wave represents the relaxation of the
ventricular muscle (ventricular repolarisation).
Atrial repolarisation occurs during ventricular
contraction, and so is not seen because of the
larger QRS complex.

77. Electrocardiogram (ECG)
The ECG described above originates from the SA
node and is called sinus rhythm. The rate of sinus
rhythm is 60–100 b.p.m.
A faster heart rate is called tachycardia(>100bpm)
and a slower heart rate, bradycardia(<60bpm).
By examining the pattern of waves and the time
interval between cycles and parts of cycles,
information about the state of the myocardium and
the cardiac conduction system is obtained.

78. Electrocardiogram (ECG)
Careful analysis of the ECG reveals a detailed picture of both
normal and abnormal heart function, and is an indispensable
clinical diagnostic tool.
The standard electrocardiograph (the instrument that
generates an ECG) uses 3, 5, or 12 leads.
The greater the number of leads an electrocardiograph uses,
the more information the ECG provides.
The term “lead” may be used to refer to the cable from the
electrode to the electrical recorder, but it typically describes
the voltage difference between two of the electrodes.

79. Electrocardiogram (ECG)
The 12-lead electrocardiograph uses 10
electrodes placed in standard locations on the
patient’s skin.
In continuous ambulatory electrocardiographs,
the patient wears a small, portable, battery-
operated device known as a Holter monitor, or
simply a Holter, that continuously monitors
heart electrical activity, typically for a period of
24 hours during the patient’s normal routine.

80. Electrocardiogram (ECG)

81. Electrocardiogram (ECG)

82. Uses of ECG
Determining and diagnosis of
Hear rate
Heart rhythm
Abnormal electrical condition
Poor blood flow to heart muscle
Heart attack
Coronary heart disease
Hypertrophy of heart

83. Blood Pressure
Blood pressure is the force or pressure that the blood exerts on the walls of
blood vessels.
Systemic arterial blood pressure maintains the essential flow of blood into and
out of the organs of the body.
Keeping blood pressure within normal limits is very important.
If it becomes too high, blood vessels can be damaged, causing clots or bleeding
from sites of blood vessel rupture.
If it falls too low, then blood flow through tissue beds may be inadequate. This is
particularly dangerous for essential organs such as the heart, brain or kidneys.

84. Blood Pressure
The systemic arterial blood pressure, usually called simply arterial blood
pressure, is the result of the discharge of blood from the left ventricle
into the already full aorta.
Blood pressure varies according to the time of day, the posture, gender
and age of the individual.
Blood pressure falls at rest and during sleep.
It increases with age and is usually higher in women than in men.

85. Systolic And Diastolic Pressures
When the left ventricle contracts and pushes blood into the aorta, the pressure
produced within the arterial system is called the systolic blood pressure. In adults it
is about 120 mmHg.
In complete cardiac diastole when the heart is resting following the ejection of
blood, the pressure within the arteries is much lower and is called diastolic blood
pressure. In an adult this is about 80 mmHg.
The difference between systolic and diastolic blood pressures is the pulse pressure.
Arterial blood pressure (BP) is measured with a sphygmomanometer and is usually
expressed with the systolic pressure written above the diastolic pressure.

86. Types Of Blood Pressure
Systolic Blood Pressure
This is the maximum pressure exerted in the arteries during the systole of
heart. The normal systolic pressure is 120mm of Hg.
Diastolic Blood Pressure
This is the minimum pressure in the arteries during the diastole of heart.
The normal diastolic blood pressure is 80 mm of Hg.
Pulse Pressure
This is the differences between the systolic and diastolic pressure.
Normally it is 40 mm of Hg.

87. Factors Determining Blood Pressure
Blood pressure is determined by cardiac output and peripheral
resistance. Change in either of these parameters tends to alter systemic
blood pressure, although the body’s compensatory mechanisms usually
adjust for any significant change.
Blood pressure = Cardiac output X Peripheral resistance

88. Factors Affecting Blood Pressure
Cardiac output
Peripheral resistance
Age
Sex
Posture
Exercise
Emotion and Excitement
Temperature
Blood volume

89. Cardiac Output
The cardiac output is the amount of blood ejected from each ventricle every
minute.
The amount expelled by each contraction of each ventricle is the stroke volume.
Cardiac output = Stroke volume X Heart rate.
In a healthy adult at rest, the stroke volume is approximately 70 mL and if the heart
rate is 72 per minute, the cardiac output is 5 L/minute.
This can be greatly increased to meet the demands of exercise to around
25L/minute, and in athletes up to 35 L/minute. This increase during exercise is
called the cardiac reserve.

90. Stroke Volume
The stroke volume is determined by the volume of blood in the ventricles
immediately before they contract, i.e. the ventricular end-diastolic
volume (VEDV), sometimes called preload.
In turn, preload depends on the amount of blood returning to the heart
through the superior and inferior venae cava (the venous return).

91. Factors Affecting Stroke Volume
VEDV (ventricular end-diastolic volume – preload)
Venous return
position of the body
skeletal muscle pump
respiratory pump
Strength of myocardial contraction
Blood volume

92. Heart Rate
Heart rate is the speed of the heart beat measured by the number of
contractions (beats) of the heart per minute (bpm).
The Main Factors Affecting Heart Rate
Gender
Autonomic activity
Age
Circulating hormones
Activity and exercise
Temperature
The baroreceptor reflex
Emotional states

93. Control Of Blood Pressure (BP)
Blood pressure is controlled in two ways:
Short-term control, on a moment-to-moment basis, which mainly
involves the baroreceptor reflex and also chemoreceptors and circulating
hormones
Long-term control, which involves regulation of blood volume by the
kidneys and the renin–angiotensin aldosterone system.

94. Short-term Blood Pressure Regulation
The cardiovascular center (CVC) is a collection of interconnected
neurons in the medulla and pons of the brain stem. The CVC receives,
integrates and coordinates inputs from:
baroreceptors (pressure receptors)
Chemoreceptors
higher centers in the brain.
The CVC sends autonomic nerves (both sympathetic and
parasympathetic) to the heart and blood vessels. It controls BP by
slowing down or speeding up the heart rate and by dilating or
constricting blood vessels. Activity in these fibers is essential for control
of blood pressure.

95. Baroreceptor Reflex: Mechanism Of Action
During Increased Blood Pressure
Increased blood pressure in artery
Increase baroreceptor activity
Signals send by cardiovascular centre in medulla via IX and X cranial nerves
Increases parasympathetic activity
Causes: vasodilation
decreased heart rate
decrease myocardial contraction
Decrease peripheral resistance
Falling blood pressure
Decrease blood pressure

96. Baroreceptor Reflex: Mechanism Of Action
During Decreased Blood Pressure
Decreased blood pressure in artery
Decrease baroreceptor activity
Signals send by cardiovascular centre in medulla via IX and X cranial nerves
Decreases parasympathetic activity
Causes: increased heart rate
increase force of cardiac contraction
Increase peripheral resistance
Increase blood pressure

97. Long-term Blood Pressure Regulation
Slower, longer lasting changes in blood pressure are effected by the
renin–angiotensin–aldosterone system (RAAS) and the action of
antidiuretic hormone (ADH).
Both of these systems regulate blood volume, thus influencing blood
pressure.
In addition, atrial natriuretic peptide (ANP), a hormone released by the
heart itself, causes sodium and water loss from the kidney and reduces
blood pressure, opposing the activities of both ADH and the RAAS.

98. Renin Angiotensin Mechanism
Decreased arterial blood pressure
Decreased blood flow of the kidney
Renin secretion from kidney increased
Renin converts angiotensinogen to angiotensin I
In lungs, angiotensin I is converted to angiotensin II by angiotensin converting enzyme
Angiotensin acts in two ways to restore blood pressure
Cause vasoconstriction of blood vessels stimulates secretion of aldosterone which
increase absorption of salt and water
from renal tubules
Increased blood pressure increased blood volume
increased blood pressure

99. Renal Body Fluid Mechanism
Increased arterial blood pressure
Increase cardiac output of kidney
Kidney excretes more amount of water and salt particularly sodium
Decreased extracellular fluid and blood volume
Decreased arterial pressure

100. Pulse
The pulse can be felt with gentle finger pressure in a superficial artery when its
wall is distended by blood pumped from the left ventricle during contraction
(systole).
The wave passes quickly as the arterial wall recoils.
Each contraction of the left ventricle forces about 60–80 mm of blood through
the already full aorta and into the arterial system.
The aortic pressure wave is transmitted through the arterial system and can be
felt at any point where a superficial artery can be pressed firmly but gently
against a bone.

101. Pulse
The number of pulse b.p.m. normally represents the heart rate and varies
considerably in different people and in the same person at different times.
An average of 60–80 is common at rest. Information that may be obtained
from the pulse includes:
the rate at which the heart is beating
the regularity of the heartbeat
the artery wall should feel soft and pliant under the fingers.

102. Pulse Rate
In health, the pulse rate and the heart rate are identical.
In certain circumstances, the pulse may be less than the heart rate.
This may occur, for example, if:
The arteries supplying the peripheral tissues are narrowed or blocked and the
blood therefore is not pumped through them with each heartbeat. Provided
enough blood is reaching an extremity to nourish it, it will remain pink in colour
and warm to touch, even if the pulse cannot be felt
There is some disorder of cardiac contraction, e.g. atrial fibrillation and the
heart is unable to generate enough force, with each contraction, to circulate
blood to the peripheral arteries.

103. Factors Affecting The Pulse Rate
Age
Gender
Body built
Exercise activity
Stress and emotions
Body temperature
Blood volume

104. Normal Pulse Rate According To Age
Infants 100-160
Preschoolers 80-110
School age 70-100
Adolescent 60-90
Adult 60-100

105. Measurement Of Pulse And Blood Pressure

106. Measurement Of Blood Pressure
https://www.youtube.com/watch?v=Gmic13mvsgo&ab_channel=PolyFitCP

107. Circulation Of Blood
The movement and distribution of blood in body in different organs
through blood vessels is called circulation.
Circulation in our body are mainly of four types:
Pulmonary Circulation
Systemic Or General Circulation
Portal Circulation
Coronary Circulation

108. Pulmonary Circulation
This is the circulation of blood from the right ventricle of the heart to the lungs and
back to the left atrium. In the lungs, carbon dioxide is excreted and oxygen is
absorbed.
The pulmonary artery or trunk, carrying deoxygenated blood, leaves the upper
part of the right ventricle of the heart.
It passes upwards and divides into left and right pulmonary arteries which enters
to the left and right lungs respectively.
Within the lung these arteries divide and subdivide into smaller arteries, arterioles
and capillaries.

109. Pulmonary Circulation
The exchange of gases takes place between capillary blood and air in the alveoli of
the lungs.
In each lung the capillaries containing oxygenated blood merge into progressively
larger venules, and eventually form two pulmonary veins.
Two pulmonary veins leave each lung, returning oxygenated blood to the left
atrium of the heart.
In this way the deoxygenated blood is pumped from right ventricle and the
oxygenated blood comes to the left atrium of heart is called pulmonary circulation.

110. Pulmonary Circulation

111. Systemic Circulation
The systemic circulation involves all the blood vessels of the body that are
not part of the pulmonary circulation.
The oxygenated blood is pumped out from the heart through aorta and
received through vena cava in right atrium is called systemic circulation.
The blood pumped out from the left ventricle is carried by the branches
of the aorta around the body and returns to the right atrium of the heart
by the superior and inferior vena cava.

112. Systemic Circulation
The blood from left ventricle is pumped out through aorta. The branches of
arch of aorta supply to head, neck and upper limb. The thoracic aorta
supplies blood to lungs, esophagus and muscles of thoracic region. The
abdominal aorta supplies stomach, spleen, liver, intestines, reproductive
organs and lower limb.
The blood is drained by superior and inferior vena cava. The blood from
upper limb, head and neck is drained by superior vena cava to right atrium.
The venous blood from lower limb, abdominal and pelvic organs is drained
by inferior vena cava into right atrium. The venous blood from thoracic area
is drained by azygous and hemiazygous vein to superior vena cava.

113. Systemic Circulation

114. Portal Circulation
In portal circulation, venous blood passes from the capillaries bed of
abdominal part of digestive system, spleen and pancreas to the liver.
It passes through a second capillary bed, the hepatic sinusoids in the
liver before entering the general circulation via the inferior vena cava.
In this way blood with high concentration of nutrients, absorbed from
the stomach and intestine goes to the liver.

115. Portal Circulation

116. Coronary Circulation
The heart is supplied with blood by the right and left coronary arteries.
Right coronary artery gives marginal, posterior interventricular
branches. Left coronary artery is larger branch and gives anterior
interventricular, circumflex and diagonal branches.
Most of the blood is collected by several small veins ( great cardiac,
middle cardiac, small cardiac, anterior cardiac, marginal) that joins to
form the coronary sinus which opens into the right atrium.

117. Coronary Circulation

118. Importance Of Circulation
To carry O2, nutrition, vitamins to the tissue.
To carry away different metabolic waste products and CO2 from tissues
for elimination.
To prevent intravascular coagulation of blood.
Helps to maintain thermal balance throughout the body.