This document provides an overview of the cardiovascular system. It discusses the composition and functions of blood, the structure and layers of the heart, types of circulation including pulmonary and systemic circulation, the cardiac cycle, heart valves and conducting system, blood pressure, electrocardiograms, and some common cardiovascular disorders like hypertension and stroke. The document is intended as an educational resource on the key components and functioning of the cardiovascular system.

1. CARDIOVASCULAR SYSTEM
By
Mr. Vinayak R. Bodhankar
M. Pharm. (QA)

2.  CONTENTS
 Blood
 Composition of Blood
 Functions of blood
 Blood group
 Coagulation of blood
 Disorders of blood
 Structure & function of Heart
 Types of Circulation
 Cardiac cycle, Arteries & Veins
 Conducting system of Heart
 ECG
 Blood pressure & its recording
 CV disorders

3.  BLOOD
 Fluid connective tissue.
 Composed of plasma (55%) & blood cells (45%).
 Physical properties of blood
 Colour – Red coloured, viscous fluid
 Thicker and heavier than water.
 Constitute 8% of body weight.
 Temp. – 380C.
 Total amount in human body – 5 to5.5 litre.
 pH – 7.4 to 7.5

4.  BLOOD PLASMA
 Slightly yellow coloured fluid.
 Composition
 Water – 90 to 92%
 Plasma protein – 6 to 8%
 Nutrients – Amino acids, glucose, etc.
 Organic waste – Urea, uric acid, etc.
 Mineral salts – Na, K, Ca, etc.
 Gases – Oxygen, carbon dioxide, etc.
 Hormones and enzymes – Antibodies and enzymes.

5.  FUNCTIONS OF BLOOD
 Transport of oxygen from lung to the body.
 Return of carbon dioxide from cell to lungs.
 Drain out waste material in the body.
 Transport of enzymes and hormones.
 Transport system for nourishment.
 Help to maintain body temp.
 Help in defensive mechanism of the body.
 Prevent the loss of body fluid and blood cells.
 Maintain acid base balance of the body.

6.  COMPOSITION OF BLOOD
1. Blood cells
a) RBC’s
b) WBC’s
i) Granulocytes: Neutrophils (70%)
Basophils (1%)
Eosinophils (4%)
ii) Agranulocytes: Lymphocytes (20%)
Monocytes (5%)
c) Thrombocytes
2. Plasma

7. RBC’s
 Small circular, disc shaped.
 Suspended in blood plasma.
 In female: 4 to 4.5 millions per cubic mm
 In male: 5 to 5.5 millions per cubic mm
 Production
o In foetal life: liver
o After birth: Red bone marrow
 Process of production is called erythropoiesis.
 Megacarocytes: from which RBC’s developed.
 Life span – 115 to 120 days.

8. WBC’s
Irregular shaped.
Normal count: 6000 to 10000 per cubic mm
1. Granulocytes
A. Neutrophils
 70% of total WBC.
 Stained with neutral dye – purple
 Responsible for defence mechanism.
B. Eosinophils
 4% of total WBC
 Stain red with eosin.
C. Basophils
 1% of total WBC.
 Stain with basic dye and appear blue colour.

9. 2. Agranulocytes
 Produced in lymph glands.
 Constitute 25% of all WBC.
i) Lymphocytes
 Constitute 23%.
 Responsible for development of immunity.
ii) Monocytes
 Constitute 2%
 Larger than lymphocytes.
 Phagocytic in action.
C. Thrombocytes
 Smaller fragments of megakaryocytes.
 Normal count: 3 to 4 lakh per cubic mm.
 Help in blood clotting.

10.  BLOOD GROUP
 Discovered by Karl Landsteiner in 1900.
 Why Blood group..?
 Blood donor
 Universal donor
 Universal acceptor
 Agglutinogen: Antigen in the membrane of RBC.
 Agglutinin: Natural antibodies.
 Agglutinins in plasma are opposite type.
 Rh antigen
 Important in case of pregnancy.
Blood group Receive from Donate to
A A, O A, AB
B B, O B, AB
AB A, B, AB, O AB
O O A, B, AB, O

11.  BLOOD CLOTTING
 Blood vessel + Injury = Rough surface.
 Platelet + rough surface = thromboplastin.
In presence of thromboplastin & Ca in plasma
 Prothrombin – Thrombin (which helps) in fibrinogen - fibrin
 Thread of fibrin + blood cell = blood clot.
P + Ca + Tp = T
T + Fg = F
F + Blood cell = clot
 Bleeding time: 1 to 4 min
 Clotting time: 3 to 6 min

12. Factor hastening blood clotting
Temp. excess than body temp.
Contact of blood with rough suface.
Slowness of blood flow.
Factor retarding blood clotting

13.  DISORDERS OF BLOOD
Anaemia: Decrease in oxygen carrying capacity of blood.
Types of anaemia:
A. Pernicious anaemia
Factor responsible for absorption of vitamin B12 is absent.
B. Microcytic anaemia
Diameter of RBC is smaller, due to deficiency of iron.
C. Haemolytic anaemia
Life span of RBC is shortened.
D. Sickle cell anaemia
Defect in haemoglobin. Life span of RBC is shortened.
E. Thalassemia
F. Megaloblastic anaemia
Polycythemia: Increase in RBC count.
Bleeding disease.
Leukemia.
Agranulocytosis.

14.  STRUCTURE OF THE HEART
 The heart is divided into the left and right side by partitions called septa (singular septum).
 The interatrial septum separates the two upper chambers, called atria (from atri/o, meaning “upper chambers”).
 The interventricular septum separates the two lower chambers, called ventricles (from ventricul/o, meaning
“lower chamber).
Interventricular Septum
Interatrial Septum

15.  LAYERS OF HEART
 The endocardium (from endo- + cardi/o + -ium, meaning “inner layer of the heart”) is formed by
endothelial cells, and it lines the interior of the heart chambers and valves.
 The myocardium (from my/o + cardi/o + -ium, meaning “heart muscle”) is the muscular middle
layer of the heart that consists of heart muscle cells.
 The epicardium (from epi- + cardi/o + -ium, meaning “outer layer of the heart”) is formed by
epithelial cells, and forms the outer cell layer of the heart.
 The pericardium (from peri- + cardi/o + -ium, meaning “surrounding the heart”) is a membranous
sac that surrounds the heart. It consist of two layers called the visceral pericardium (adheres to the
epicardium) and parietal pericardium (the outer coat). The space between these two layers is called
pericardial cavity and it contains pericardial fluid.

16.  HEART CHAMBERS AND VALVES
 The human heart has four chambers, which are responsible for pumping blood and
maintaining blood circulation throughout the body.
 The four chambers are name:
The right atrium
The left atrium
The right ventricle
The left ventricle
 Blood is only pumped to one direction.
 Four heart valves ensure that blood does not flow backward within the heart.

17.  HEART VALVES
 The tricuspid valve (from tri- + cuspid, meaning “having three points”) located between right atrium and
ventricle.
 The pulmonary valve (from pulmon/o, meaning “lungs”) located between right ventricle and pulmonary artery.
Also called semilunar valve.
 The mitral valve, also called bicuspid valve ( from bi- + cuspid, meaning “having two points”) located
between left atrium and ventricle.
 The aortic valve located between left ventricle and aorta.
 The tricuspid and bicuspid valves are also called atrioventricular valves (meaning “located between the atrium and
ventricle”).

18.  FUNCTIONS OF THE HEART
 The heart functions to circulate blood around the body. The right
and left side of the heart pump blood into two different
circulations.
 The right side pumps deoxygenated blood into the pulmonary
circulation, while the left side pumps oxygenated blood into the
systemic circulation.
 The right atrium receives deoxygenated blood from the body
tissues via the superior and inferior vena cava.
 The blood enters the right atrium, which pumps the blood into
the right ventricle. The tricuspid valve prevents blood from
flowing backward into the right atrium. The right ventricle
pumps the blood into the pulmonary artery via the pulmonary
valve.

19.  The pulmonary artery will deliver the deoxygenated blood to the lungs, where gas exchange occurs.
 Oxygen is taken from the air into the blood (now called oxygenated blood), while carbon dioxide is
expelled from the blood into the air. The oxygenated blood returns to the left side of the heart via the
 pulmonary veins.
 The oxygenated blood enters the left atrium.
 The left atrium pumps blood into the left ventricle. The mitral valve prevents blood from flowing
backward into the left atrium.
 The left ventricle pumps the blood into the aorta and systemic circulation. The oxygenated
blood is delivered everywhere in the body (besides the lungs).

20.  PULMONARY CIRCULATION
 Pulmonary circulation begins at the right ventricle, where the deoxygenated blood from the body
tissues is pumped into the pulmonary arteries and to the lungs.
 In the lungs, the blood exchanges carbon dioxide (waste product of cellular respiration) to oxygen.
 The oxygenated blood them travels back to the heart and the left atrium, via the pulmonary vein.

21.  SYSTEMIC CIRCULATION
 The systemic circulation begins at the left ventricle that pumps oxygenated blood into the
aorta.
 Aorta branches out into smaller arteries, which carry the oxygenated blood to the rest of the
body (with the exception of lungs).
 Oxygen is delivered to the body tissues and exchanged to carbon dioxide. The now deoxygenated
blood is carried back to the heart and the right atrium via veins.

22.  PORTAL CIRCULATION
 Collection by portal vein – digestive organ.
 Pour into liver.
 Liver – already supplied with oxy. blood by hepatic artery.
 Mixing take place.
 Collected by hepatic vein.
 Pour into inferior venacava.

23.  CARDIAC CYCLE
 One complete sequence of atrial and ventricular systole and diastole.
 Cycle of events that occurs as the heart contract and relaxes.
 Contraction of atria – short
 Contraction of ventricle – long.
 Time required for one cardiac cycle is 0.8 sec.
 SA node – near the opening of superior vena cava in RA.
 AV node – On the atrioventricular septum.
 Stroke volume: Amount of blood ejected from heart at each contraction of ventricle.
 Cardiac output: Amount of blood ejected each minute.
Stroke volume * heart rate

24.  ARTERIES VS VEINS
 The blood vessels that carry blood AWAY from heart are called arteries.
 The blood vessels that carry blood TOWARD the heart are called veins.
 Only in systemic circulation arteries carry oxygenated blood, while in the pulmonary circulation arteries carry
deoxygenated blood.

25.  CONDUCTION SYSTEM OF THE HEART
The conduction system of the heart controls the rate and pattern of your heartbeat.

26.  SINOATRIAL(SA) NODE
 Myocardium contracts after it receives an electrical impulse generated by a specialized tissue located within
the right atrium.
 This is called the sinoatrial node (SA node), also called the pacemaker of the heart. The SA node is a
bundle of neurons that triggers the contraction of the atria during the cardiac cycle.
 The electrical currents next reach the ventricles, which contract after the atria.
 The SA node initiates approximately 75 electrical impulses each minute, with variation between individuals’
age and general health.

27.  THE PURKINJE FIBERS
 The Purkinje fibers are cells in the inner ventricle walls, just beneath the endocardium. These fibers run
between the ventricles to the apex (bottom) of the heart. The Purkinje fibers play a crucial role in the cardiac
cycle.
 When an electrical stimulus leaves the AV node, it travels via the bundle of His and branches to the Purkinje
fibers. These fibers then carry the impulse through the inner wall of each ventricle. This causes the ventricles to
contract after the atria contract.
 The ventricle contraction forces blood from the right ventricle to the lungs (pulmonary circulation) and
from the left ventricle to the body (systemic circulation).
 These three elements generate a healthy heart rhythm known as sinus rhythm. The rhythm, or contraction of
the heart pumps blood throughout the body. In roughly a minute’s time, blood travels from the heart to the
body and back.

28.  ECG AND THE P-QRS-T SYSTEM
An electrocardiogram (from electr/o + cardi/o + -gram), also called an EKG or ECG, is a diagnostic
test used to record and trace the electrical activity of the heart.

29.  THE ELECTRICALACTIVITY OF THE HEART
 The electrical activity in the heart is displayed as a P wave, QRS interval and T wave.
 The P wave correlates to atrial depolarization (systole) and atrial contractions. There is not a wave
associated with atrial repolarization as it occurs during ventricular depolarization (during the QRS
interval).
 The QRS complex correlates to ventricular depolarization (systole) as the ventricles contract. The Q
wave is the beginning, the R wave the middle of the contraction, and the S wave is the end of
ventricular depolarization, and beginning of ventricular repolarization (diastole).
 The T wave correlates to ventricular repolarization (diastole).

30.  BLOOD PRESSURE
 Types: Systolic & diastolic.
 Measured in terms of mm of Hg.
 Normal systolic: 120 mm of Hg (100-150)
 Normal diastolic: 90 mm of Hg (60-90)
 Pulse pressure: Difference between systolic & diastolic B.P.
 Measured with the help of instrument “Sphygmomanometer”
 Factor affecting blood pressure
 Physiological conditions.
 Emotional conditions.
 Age of individual.
 Body weight.

31.  DISORDERS OF HEART
 Rheumatic heart disease
Streptococcal infection. (Haemolytic)
 Bacterial endocarditis
Non haemolytic infection.
 Coronary artery occlusion
Myocardial infaract
 Congenital heart disease
Defect in formation of septum.
 Arrhythmia
Disturbance in rhythm
 Atherosclerosis
Deposition of fatty material.

32.  HEALTH CONDITIONS
Hypertension:
Hypertension is an abnormal condition that is primarily caused by high blood cholesterol.
 Excess cholesterol is deposited on the arterial walls as plaques.
 These plaques make the lumen of the artery narrower, which causes the blood to flow with higher
pressure.
 If an artery becomes completely blocked, the cells supported by that artery will suffer from lack of oxygen and die.
 If this happens in the coronary arteries, which provide blood to the heart, the result can be myocardial
infarction (heart attack).

33.  STROKE
An artery leading to the brain can become blocked. This can cause a cerebral vascular accident, known as a
stroke.

34.  HYPOTENSION
 Hypotension is also an abnormal condition, in which the blood flows with low pressure.
 Hypotension occurs when a large volume of water or blood is lost from the body.
 The body’s loss of water, dehydration, can occur during diarrhea or vomiting.
 The body’s loss of blood, hemorrhage, can occur due to blood disorders or injury to the blood vessels
(trauma).
 Hypotension can result in shock.