This document provides an overview of the cardiovascular system and human heart. It begins with definitions and functions of the cardiovascular system. It then describes the internal and external structure of the heart, including the four chambers, valves, blood vessels, and conducting system. Key concepts covered include the cardiac cycle, blood pressure, electrocardiogram, coronary and systemic circulation. Common heart conditions such as coronary artery disease, heart attack, arrhythmias and valve disease are also summarized.

1. I d pharma
Human anatomy and physiology
Cardiovascular system
 Lakshman v bendre
 Asst. prof
 Dept.pharmacology

2. Table of Contents
1. Introduction
2. Position of heart
3. Structure of the Human Heart
4. Physiology of heart
5. Coronary circulation
6. Conducting system
7. Cardiac cycle
8. Cardiac output
9. Electrocardiogram
10. Blood pressure
11. Functions of heart
12. Types of circulation
13. Disorders of heart

3. CARDIO~VASCULAR
SYSTEM
“heart” “vessels”
Definition: There is
continuous flow of blood
through out the human
body the process is known
as blood circulation.
Made up of heart, blood vessels,
and blood
Functions
Heart- pump blood
Vessels- (veins, arteries,
capillaries) circulate blood
Blood- transports nutrients,
waste, hormones, oxygen,
antibodies

4. Introduction to the Human
Heart
 The human heart is one of the
most important organs
responsible for sustaining life.
It is a muscular organ with
four chambers. The size of the
heart is the size of about a
clenched fist.
 The human heart functions
throughout a person’s lifespan
and is one of the most robust
and hardest working muscles
in the human body.

5. Position of Heart in Human Body
 The human heart is located between the lungs
in the thoracic cavity, slightly towards the left of
the sternum (breastbone). It is derived from the
embryonic mesodermal germ layer.

6. EXTERNAL STRUCTURE OF THE HUMAN HEART
 The human heart is hollow muscular organ which
is situated to the left of the chest and is enclosed
within a fluid-filled cavity described as the
pericardial cavity. The walls and lining of the
pericardial cavity are made up of a membrane
known as the pericardium.

7. • The pericardium is a fiber membrane
found as an external covering around the
heart. It protects the heart by producing a
serous fluid, which serves to lubricate the
heart and prevent friction between the
surrounding organs. Apart from the
lubrication, the pericardium also helps by
holding the heart in its position and by
maintaining a hollow space for the heart
to expand itself when it is full. The
pericardium has two exclusive layers—
• Visceral Pericardium: It directly covers
the outside of the heart.
• Parietal Pericardium: : It forms a sac
around the outer region of the heart that
contains the fluid in the pericardial cavity.

8. STRUCTURE OF THE HEART WALL
The heart wall is made up of 3 layers, namely:
 Epicardium – Epicardium is the outermost layer of the heart. It
is composed of a thin-layered membrane that serves to lubricate
and protect the outer section.
 Myocardium – This is a layer of muscle tissue and it constitutes
the middle layer wall of the heart. It contributes to the thickness
and is responsible for the pumping action.
 Endocardium – It is the innermost layer that lines the inner
heart chambers and covers the heart valves. Furthermore, it
prevents the blood from sticking to the inner walls, thereby
preventing potentially fatal blood clots

9. INTERNAL STRUCTURE OF
HEART
 The internal structure of the heart
is rather intricate with several
chambers and valves that control
the flow of blood.
 Chambers of the Heart
 Avian and mammalian hearts
consists of four chambers.
Humans are mammals; hence, we
have four chambers, namely:
1. Left atrium
2. Right atrium
3. Left ventricle
4. Right ventricle

11.  Atria are thin, less muscular walls and smaller than
ventricles. These are the blood-receiving chambers
that are fed by the large veins.
 Ventricles are larger and more muscular chambers
responsible for pumping and pushing blood out to the
circulation. These are connected to larger arteries that
deliver blood for circulation.
 The right ventricle and right atrium are comparatively
smaller than the left chambers. The walls consist of
fewer muscles compared to the left portion, and the
size difference is based on their functions. The blood
originating from the right side flows through the
pulmonary circulation, while blood arising from the left
chambers is pumped throughout the body.
 SEPTUM: Right and left atria are separated by inter
auricular septum where as Right and left ventricles
are separated by inter ventricular septum.

12. VALVES
 Valves are flaps of fibrous tissues located in
the cardiac chambers between the veins.
They ensure that the blood flows in a single
direction (unidirectional). Flaps also prevent
the blood from flowing backwards. Based
on their function, valves are of two types:
1. Atrioventricular valves
2. Semilunar valves
 Atrioventricular valves : are between
ventricles and atria.
 The valve between the right ventricle and
right atrium is the tricuspid valve and the
one which is found between the left
ventricle and left atrium is known as the
mitral valve (bicuspid valve)
 Semilunar valves : These are present in
Aorta and Pulmonary artery.
 the valve which is located between the left
ventricle and aorta called Aortic valve. It is
also found between the pulmonary artery
and right ventricle called Pulmonary valve.

13. Blood Vessels
In humans with closed circulatory systems,
the blood flows within vessels of varying sizes.
The external structure of the heart has many
blood vessels that form a network, with other
major vessels emerging from within the
structure. The blood vessels typically
comprise the following:
1.Superior venacava and inferior venacava:
They carry deoxygenated blood to the right
atrium of the herat.
2.Pulmonary artery : Carries deoxygenated
blood to the lung for purification
3.Pulmonary vein: They carry oxygenated
blood to the left atrium. Of the heart
4.Systemic Aorta: Carries oxygenated blood
to the various parts of the body from left
ventricle.
Capillaries are tiny, tube-like vessels which
form a network between the arteries to veins.

14. ARTERY VEINS
Involved in carrying oxygenated
blood except for pulmonary
arteries
Involved in carrying deoxygenated
blood except for pulmonary veins
Red in colour. Blue in colour.
Located deep within the body. Peripherally located closer to the
skin.
Carry blood away from the heart
to various parts of the body.
Carry blood towards the heart
from the various parts of the body.
Comparatively higher oxygen
level
Comparatively low oxygen level.
High pressure, as the blood flows
by the pumping pressure of the
heart.
Low pressure, as the blood flows
by the capillary action of the
veins.

16. T.S OF ARTERY AND VEIN

17. PATHWAY OF BLOOD CIRCULATION

19. MECHANISM OF BLOOD CIRCULATION
Blood comes into the right atrium from the
body, moves into the right ventricle and is
pushed into the pulmonary arteries in the lungs.
After picking up oxygen, the blood travels
back to the heart through the pulmonary veins
into the left atrium, to the left ventricle and out to
the body's tissues through the aorta.

21. CORONARY
CIRCULATION(Blood supply
to the heart):
It is the circulation of blood to
the heart first bronets of
aorta in the coronary artery
which supplies oxygenated
blood to the heart muscle it
self,

22. CONDUCTING SYSTEM
OF HEART
The impulses for
contracton of the heart are
transmitted through the
conducting system of
heart.
This pathway is made up
of 4 elements:
1. Sino-atrial (SA) node.
2. Atrio-ventricular (AV)
node.
3. Bundle of His.
4. Purkinje fibres.

23. 1. Sino-atrial (SA) node: It is the specialized cells in the
wall of right atrium near the opening of superior
venacava.
 The SA Node is often called as PACEMAKER
because
it initiates impulse of contraction of heart.
 This cardiac action potential spread over the right
and left atria causing them to contract blood enters
into ventricles.
2. Atrio-ventricular (AV) node: It is also specialized
cells
situated in the wall of the inter septum near the atrio-
ventricular opening.
 Impulse of SA Node passes to this AV Node.

24. 3. Bundle of His: It is a specialized mass fibers that originated from AV
Node which further divides into left and right branches.
4. Purkinje fibers : Right and left branches of Bundle of his breaks up
into
fine fibrous called Purkinje fibers.
 . These fibers convey the impulse of contraction from AV Node to the
entire ventricle system
 Thus the entire sequence of conduction takes place.

25. Cardiac Cycle
“Cardiac cycle refers to the sequence of events that
take place when the heart beats.”
 The cardiac cycle attributes to a comprehensive
heartbeat from its production to the commencement
of the next beat. It comprises diastole, the systole,
and the intervening pause.
 The occurrence of a cardiac cycle is illustrated by a
heart rate, which is naturally indicated as beats per
minute
 A healthy human heart beats 72 times per minute
which states that there are 72 cardiac cycles per
minute.
 The cardiac cycle involves a complete contraction and
relaxation of both the atria and ventricles and the
cycle last approximately 0.8 seconds.

26. Cardiac Cycle Phases
Following are the different phases that
occur in a cardiac cycle:
1) Atrial Diastole
2) Atrial Systole
3) Isovolumic Contraction
4) Ventricular Ejection
5) Isovolumic Relaxation
6) Ventricular Filling Stage

27. Duration of Cardiac Cycle
In a normal person, a heartbeat is 72 beats/minute. So, the
duration of one cardiac cycle can be calculated as:
1/72 beats/minute=.0139 minutes/beat
At a heartbeat 72 beats/minute, duration of each
cardiac cycle will be 0.8 seconds.
Duration of different stages of the cardiac cycle is given
below:
Atrial systole: continues for about 0.1 seconds
Ventricular systole: continues for about 0.3 seconds
Atrial diastole: continues for about 0.7 seconds
Ventricular diastole: continues for about 0.5 seconds

28.  Cardiac output : The amount of blood
the heart pumps through the circulatory system in a
minute.
 stroke volume :The amount of blood put out by
the left ventricle of the heart in one contraction is
called the stroke volume
 Heart rate :Your pulse rate, also known as
your heart rate, is the number of times your heart
beats per minute. A normal resting heart rate should
be between 60 to 100 beats per minute, but it can
vary from minute to minute.
 The stroke volume and the heart rate determine the
cardiac output. A normal adult has a cardiac output
of 4.7 liters (5 quarts) of blood per minute

29. Cardiac output Stroke volume Heart Rate
5040 ml/min 70 ml 72/min

30. Electrocardiogram
An electrocardiogram is a test that
measures the electrical activity of
the heartbeat. With each beat, an
electrical impulse (or “wave”) travels
through the heart. This wave causes
the muscle to squeeze and pump
blood from the heart.
 The ECG recordings are designated
by letters P, Q, R, S, T.
 Wave ‘’P’’ represents Atrial
contractions
 Wave ‘‘Q R S’’ represents
Ventricular contraction.
 Wave ‘‘T’’ represents Ventricular
relaxation.

31. Electrocardiography is the process of
producing an electrocardiogram

32. Blood pressure
Blood pressure is the pressure of circulating blood
against the walls of blood vessels. the term "blood
pressure" refers to the pressure in the large
arteries.
There are two types of blood pressure
1. Systolic blood pressure
2. Diastolic blood pressure
Systolic BP- maximum pressure during systole is 120 mmHg
Diastolic BP- minimum pressure during diastole is 80 mmHg
Normal blood pressure 120/80 mmHg
Pulse pressure- It is the difference between systolic and diastolic BP

33. RECORDING OF BP
A sphygmomanometer is a device that
measures blood pressure. It is
composes of an inflatable rubber cuff,
which is wrapped around the arm. A
measuring device indicates the cuff's
pressure. A bulb inflates the cuff and a
valve releases pressure. A
stethoscope is used to listen to arterial
blood flow sounds.
SIGNIFICANCE:
a. Measuring blood pressure
b. Monitoring effectiveness of
medications.
c. Helps to control hypertension
d. It helps to detect various

34. ARETERY AND VENOUS
SYSTEM
The arterial system is the higher-
pressure portion of
the circulatory system, with
pressure varying between the
peak pressure during heart
contraction ( systolic pressure )
and the minimum (diastolic)
pressure between contractions
when the heart expands and
refills.
The venous system is that part of
the circulation in which the blood
is transported from the periphery
back to the heart. We distinguish
between the superficial and the
deep venous systems.

35.  TYPES OF CIRCULATION
1. Pulmonary circulation is a portion of
circulation responsible for carrying
deoxygenated blood away from the
heart, to the lungs and then brings
oxygenated blood back to the heart.
2. Systemic circulation is another
portion of circulation where
the oxygenated blood is pumped
from the heart to every organ and
tissue in the body, and deoxygenated
blood comes back again to the heart.

36. FUNCTIONS OF THE HEART
The four main functions of the heart are:
1. Pumping oxygenated blood to the other body
parts.
2. Pumping hormones and other vital substances
to different parts of the body.
3. Receiving deoxygenated blood and carrying
metabolic waste products from the body and
pumping it to the lungs for oxygenation.
4. Maintaining blood pressure.

37. Heart d Conditions OR Disorders of heart
1. Coronary artery disease : Over the years, cholesterol plaques can narrow the
arteries supplying blood to the heart. The narrowed arteries are at higher risk
for complete blockage from a sudden blood clot (this blockage is called a heart
attack).
2. Stable angina pectoris: Narrowed coronary arteries cause predictable chest
pain or discomfort with exertion. The blockages prevent the heart from
receiving the extra oxygen needed for strenuous activity. Symptoms typically
get better with rest.
3. Unstable angina pectoris: Chest pain or discomfort that is new, worsening, or
occurs at rest. This is an emergency situation as it can precede a heart attack,
serious abnormal heart rhythm, or cardiac arrest.
4. Myocardial infarction (heart attack): A coronary artery is suddenly blocked.
Starved of oxygen, part of the heart muscle dies.
5. Arrhythmia(dysrhythmia): An abnormal heart rhythm due to changes in the
conduction of electrical impulses through the heart. Some arrhythmias are
benign, but others are life-threatening.
6. Congestive heart failure: The heart is either too weak or too stiff to effectively
pump blood through the body. Shortness of breath and leg swelling are
common symptoms.
7. Cardiomyopathy: A disease of heart muscle in which the heart is abnormally
enlarged, thickened, and/or stiffened. As a result, the heart's ability to pump
blood is weakened.
8. Myocarditis: Inflammation of the heart muscle, most often due to a viral
infection.
9. Pericarditis: Inflammation of the lining of the heart (pericardium). Viral

38. 10. Pericardial effusion: Fluid between the lining of the heart
(pericardium) and the heart itself. Often, this is due to pericarditis.
11. Atrial fibrillation: Abnormal electrical impulses in the atria cause
an irregular heartbeat. Atrial fibrillation is one of the most common
arrhythmias.
12. Pulmonary embolism: Typically a blood clot travels through the
heart to the lungs.
13. Heart valve disease: There are four heart valves, and each can
develop problems. If severe, valve disease can cause congestive
heart failure.
14. Heart murmur: An abnormal sound heard when listening to the
heart with a stethoscope. Some heart murmurs are benign; others
suggest heart disease.
15. Endocarditis: Inflammation of the inner lining or heart valves of
the heart. Usually, endocarditis is due to a serious infection of the
heart valves.
16. Mitral valve prolapse: The mitral valve is forced backward slightly
after blood has passed through the valve.
17. Sudden cardiac death: Death caused by a sudden loss of heart
function (cardiac arrest).
18. Cardiac arrest: Sudden loss of heart functionaa