heart blood vessels lymphatic system

2. Mrs. Neha Sharma

3. OBJECTIVES
•Circulatory system
- Parts Of Circulatory System
- Anatomy Of Heart (Diagram)
- Cardiac Cycle
- Types Of Circulation
- Blood-composition
- Arterial System And Venous System

4. INTRODUCTION
 The circulatory system is also known as the Cardiovascular System or the Vascular
System.
 The essential components of the human cardiovascular system are
the Heart, Blood and Blood Vessels.

5. The world heart day is celebrated on 29 September.

6. Function of Heart
 The human heart is one of the most important organs responsible for
sustaining life. It is the most vital organ of the human body.
The heart performs the following important functions:
• The primary function of the heart is to pump blood throughout the body.
• It supplies oxygen and nutrients to the tissues and removes carbon dioxide
and wastes from the blood.
• It also helps to maintain adequate blood pressure throughout the body.

7. • The heart pumps around 5 litres 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.
• The average male heart weighs around 280 to 340 grams (10 to 12
ounces). In females, it weighs around 230 to 280 grams (8 to 10
ounces).
• An adult heart beats about 60 to 100 times per minute.

8. TYPES OF CIRCULATION
• 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.
• 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.

9. • Coronary circulation is an essential portion of the
circulation, where oxygenated blood is supplied to the heart.
This is important as the heart is responsible for supplying
blood throughout the body.

10. • first functional organ to develop and
starts to beat and pump blood at
around 3 weeks or 21 - 22 days.
• The human heart is located within the
thoracic cavity, medially between the
lungs in the space known as the
mediastinum. About two-thirds of your
heart is on the left side of your chest,
and one-third is on the right side
• The heart is a hollow muscular organ
about the size of a fist, and is roughly
cone-shaped. It is about 12cm long,
9cm across the broadest point and
about 6cm thick.

13. • The pericardium is a thin double-membraned sac that surrounds heart and
attaches to the mediastinum.. It protects and lubricates your heart and keeps it in
place within chest.
• The pericardium has two layers:
• Fibrous pericardium is the outer layer. It’s made from thick/dense
connective tissue and is attached to your diaphragm. It holds your heart in
place in the chest cavity and protects from infections.
• Serous pericardium is the inner layer made up of mesothileal layer . It’s
further divided into two more layers: the visceral and parietal layers. The
serous pericardium helps to lubricate your heart.

15. • Between the layers is the pericardial cavity, a potential space filled
with 15 - 50 ml of serous pericardial fluid. Pericardial fluid is
secreted by pericardial cells, and it is this fluid that reduces friction
between the parietal and visceral layer during heart contractions.

16. LAYERS OF HEART
• The heart wall is made up of three layers: the inner endocardium,
middle myocardium and outer epicardium.
Layers of heart:
• The wall of the heart is made up of three layers:
• Epicardium- this is a protective layer made of connective tissues.
• Myocardium- this layer forms the heart muscles.
• Endocardium- this is the innermost layer and protects the valves and
the heart.

17. • The heart is made up of four chambers: two upper chambers known
Atrias as the left atrium and right atrium and two lower chambers
called Ventricles as the left and right ventricles.

18. Chambers of heart
• Left atrium
• Right atrium
• Left ventricle
• Right ventricle
• 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.

21. Valves of Heart
There is a valve through which blood passes before leaving each chamber of the
heart.
The valves are made of strong, thin flaps of tissue called leaflets or cusps
The valves prevent the backward flow of blood.
These valves are actual flaps that are located on each end of the two ventricles
(lower chambers of the heart).
They act as one-way inlets of blood on one side of a ventricle and one-way
outlets of blood on the other side of a ventricle.
Normal valves have three flaps, except the mitral valve, which has two flaps.

22. • The leaflets are attached to and supported by a ring of tough, fibrous
tissue called the annulus. The annulus helps to maintain the proper
shape of the valve.
• The leaflets of the mitral and tricuspid valves are also supported by:
• Chordae tendineae: tough, fibrous strings. These are similar to the
strings supporting a parachute.
• Papillary muscles: part of the inside walls of the ventricles.
• The chordae tendineae and papillary muscles keep the leaflets stable
to prevent blood from flowing backward.

23. The four heart valves include the following:
• Tricuspid valve: located between the right atrium and the right
ventricle
• Pulmonary valve: located between the right ventricle and the
pulmonary artery
• Mitral valve: located between the left atrium and the left ventricle
• Aortic valve: located between the left ventricle and the aorta

24. How heart valves function???
As the heart muscle contracts and relaxes, the valves open and
shut, letting blood flow into the ventricles and atria at
alternate times.

25. Tricuspid valve
Mitral/Bicuspid
valve
Atrioventricular
valves
Pulmonary
valve
Aortic valve
Semilunar
valves

27. Four valves regulate blood flow through the heart:
• The tricuspid valve regulates blood flow between the right atrium
and right ventricle.
• The pulmonary valve controls blood flow from the right ventricle
into the pulmonary arteries, which carry blood to lungs for
oxygenation.
• The mitral valve lets oxygen-rich blood from lungs pass from the
left atrium into the left ventricle.
• The aortic valve opens the way for oxygen-rich blood to pass from
the left ventricle into the aorta, (body’s largest artery).

29. A wall of muscle called the Septum separates the left and right atria
and the left and right ventricles.
The left ventricle is the largest and strongest chamber in the heart.
Largest & longest artery is the Aorta.
Largest vein is Inferior Vena Cava.

30. CARDIAC MUSCLE
• Striated and resemble the skeletal muscle fibre
• Sarcomere is the functional unit
• Sarcomere of the cardiac muscle has all the contractile proteins, namely actin,
myosin, troponin tropomyosin.

31. The physiological properties of the cardiac muscle are:
1. Rhythmicity :- the ability of the heart to initiate its beat continuously
and regularly without external stimulation
2. Excitability:- the ability of cardiac muscle to respond to a stimulus of
adequate strength & duration
3. Contractility :- ability of cardiac muscle to contract in response to
stimulation
4. Conductivity:- property by which excitation is conducted through the
cardiac tissue

32. CARDIAC CONDUCTION SYSTEM
Cardiac conduction is the rate at which the heart conducts electrical
impulses. These impulses cause the heart to contract and then relax. The
constant cycle of heart muscle contraction followed by relaxation causes
blood to be pumped throughout the body. Cardiac conduction can be
influenced by various factors including exercise, temperature, and endocrine
system hormones.

34. The cardiac conduction system is a collection of nodes and
specialised conduction cells that initiate and co-ordinate contraction of
the heart muscle. It consists of:
• Sinoatrial node (SA node)
• Atrioventricular node (AV node)
• Atrioventricular bundle (bundle of his)
• Purkinje fibres

35. SINOATRIAL NODE (SA NODE)
• It is located at the junction of the superior vena cava and the right atrium.
• Generates electrical impulses at 60-100 times per minutes.
• It is controlled by the sympathetic & parasympathetic nervous system.
• The SA node continuously produces action potential, setting the rhythm of the
heart and so is known as the heart's natural pacemaker.
• SA node transmits impulse directly to the two atria simultaneously causing them
to contract.
• Intra-atrial tracts - Bachmann's Bundle
• As the electrical impulse leaves the SA node, it is conducted through the left atria
by way of the bachmann's bundles, through the right atria, via the atrial tracts

36. ATRIOVENTRICULAR NODE ( AV NODE)
• Located in the lower aspect of the atrial septum.
• Receives electrical impulses from the SA node.
• If SA node fails, the AV node can initiate and sustain a heart rate of
40-60 beats/minute.
• The AV node sends an impulse into the ventricles.
• The lower heart chambers (ventricles) contract or pump
• Also called “secondary pacemaker”.

37. THE BUNDLE OF HIS/ ATRIOVENTRICULAR
BUNDLE
• The atrioventricular bundle (bundle of his) is a continuation of the
specialised tissue of the AV node, and serves to transmit the electrical
impulse from the AV node to the purkinje fibres of the ventricles.
• It descends down the membranous part of the interventricular septum,
before dividing into two main bundles:
• Right bundle branch – conducts the impulse to the purkinje fibres of the
right ventricle
• Left bundle branch – conducts the impulse to the purkinje fibres of the left
ventricle.

38. PURKINJE FIBERS
• Are part of the specialized conduction network of the heart that
ensures that the wave of excitation spreads rapidly and almost
synchronously to the ventricular muscle mass.
• Found in the sub-endocardium.
• They are larger than cardiac muscle cells, but have fewer myofibrils,
lots of glycogen and mitochondria

39. NERVOUS SYSTEM
Heart is supplied by 2 branches of the autonomic nervous system
A. Sympathetic nervous system (or adrenergic)
• 1. Accelerates the heart
• 2. Two chemicals are influenced by the sympathetic system – epinephrine & norepinephrine
• 3. These chemicals increase heart rate, contractibility, automaticity, and AV conduction
B. Parasympathetic nervous system ( or cholinergic)
• 1. Slows the heart
• 2. The vagus nerve is one of this systems nerves, when stimulated slows heart rate and AV
conduction.

41. IMPORTANT TERMS
• Polarization is the existence of opposite electrical charges on either side of a cell
membrane (difference in inside a cell versus the outside of the cell)
• Depolarization is the state which the cell membrane change from positive to negative
charged outside the cell and from negative to positive charge inside the cell.
(contraction)
• Repolarization is the state which the cell membrane change back to its resting stage
i.e, from negative to positive charge outside the cell and from positive to negative
charge inside the cell. (relaxation)

42. CARDIAC CYCLE
• The cardiac cycle is defined as a sequence of alternating contraction
and relaxation of the atria and ventricles in order to
pump blood throughout the body. It starts at the beginning of one
heartbeat and ends at the beginning of another.
• The cycle last approximately 0.8 seconds.

43. • The period of contraction that the heart undergoes while it pumps blood into
circulation is called SYSTOLE.
• The period of relaxation that occurs as the chambers fill with blood is
called DIASTOLE.

46. CARDIAC CYCLE PHASES
• Atrial diastole: in this stage, chambers of the heart are calmed. That is when the
aortic valve and pulmonary artery closes and atrioventricular valves open, thus
causing chambers of the heart to relax.
• Atrial systole: at this phase, blood flow from atrium to ventricle and at this period,
atrium contracts.
• Isovolumic contraction: at this stage, ventricles begin to contract. The
atrioventricular valves, valve, and pulmonary artery valves close, but there won’t be
any transformation in volume.
• Ventricular ejection: here ventricles contract and emptying. Pulmonary artery and
aortic valve close

47. • Isovolumic relaxation: in this phase, no blood enters the ventricles and
consequently, pressure decreases, ventricles stop contracting and begin to relax.
Now due to the pressure in the aorta – pulmonary artery and aortic valve close.
• Ventricular filling stage: in this stage, blood flows from atria into the ventricles.
It is altogether known as one stage (first and second stage). After that, they are
three phases that involve the flow of blood to the pulmonary artery from
ventricles.

48. BLOOD PRESSURE
SBP : 90-130 mmHg
DBP : 60-90 mmHg
PULSE PRESSURE : 30-40 mmHg
Note : 1. Small /Narrow cuff leads to false high BP
2. Large/Wide cuff leads to false low BP

49. HEART SOUNDS
Heart sounds are created from blood flowing through the
heart chambers as the cardiac valves open and close during
the cardiac cycle. Heart sounds can be auscultated with the
help of Stethoscope.
LUB DUB

50. HEART SOUNDS

53. CARDIAC OUTPUT
SV : STROKE VOLUME ( Volume of blood pumped from the left
ventricle per beat) Normal stroke volume is 70 ml.
HR : HEART RATE ( Number of times the heart beats in one minute)
Normal heart rate is 72/min.
CO : CARDIAC OUTPUT (The amount of blood your heart pumps each
minute.) ( 5-6 L/MIN)
CO= SV * HR

54. ECG /EKG (Electrocardiogram)
• Willem Einthoven
• Measures the electrical activity of the heartbeat.
Depolarization Repolarization

55. ATRIAL DEPOLARIZATION
VENTRICULAR DEPOLARIZATION
VENTRICULAR REPOLARIZATION

56. There are three main components to an ECG:
• The P wave, which represents the depolarization
(contraction) of the atria
• The QRS complex, which represents the depolarization
(contraction) of the ventricles
• The T wave, which represents the repolarization
(relaxation) of the ventricles.

57. • PR interval :- the PR interval is measured from the beginning
of the P wave to the beginning of the QRS complex. This
interval reflects the time the electrical impulse takes to
travel from the sinus node through the AV node.
• ST segment :- the ST segment connects the QRS complex
and the T wave; it represents the period when the ventricles
are depolarized.
• T wave :- the T wave represents the repolarization of the
ventricles.

59. • Blood vessels are flexible tubes that carry blood, associated oxygen,
nutrients, water, and hormones throughout the body.
• Blood vessels are key components of the systemic and pulmonary
circulatory systems that distribute blood throughout the body.
• Blood vessels consist of arteries, arterioles, capillaries, venules , and
veins.
• Vessel networks deliver blood to all tissues in a directed and
regulated manner.

61. There are three major types of blood vessels:
arteries that carry blood away from the heart,
branching into smaller arterioles throughout the
body and eventually forming the capillary network..
Capillaries in turn merge into venules, then into
larger veins responsible for returning the blood to
the heart.

62. Capillaries
• Capillaries are the smallest blood vessels in the body,
connecting the smallest arteries to the smallest veins.
• These vessels are often referred to as the
"Microcirculation.“
• Capillaries facilitates efficient chemical exchange between
tissue and blood

63. TYPES OF CAPILLARIES
• Continuous capillaries have continuous, unbroken walls consisting of cells
that are connected by tight junctions. They are present in muscle, skin,
fat, and nerve tissue. Most capillaries are of this type.
• Fenestrated capillaries have continuous walls between endothelial cells,
but the cells have numerous pores (fenestrations) that increase their
permeability. These capillaries are found in the kidneys, lining the small
intestine, and in other areas where a high transfer rate of substances into
or out of the capillary is required.
• Sinusoidal capillaries (sinusoids) have large gaps between endothelial cells
that permit the passage of blood cells. These capillaries are found in the
bone marrow, spleen, and liver.

65. Arteries and veins are comprised of three distinct layers
while the much smaller capillaries are composed of a single
layer
• Tunica intima: the innermost layer of a blood vessel.
• Tunica media: the middle layer of a blood vessel.
• Tunica externa: the outermost layer of a blood vessel.

67. Tunica Intima
The inner layer (tunica intima) is the thinnest layer, formed from a
single continuous layer of endothelial cells and supported by a
subendothelial layer of connective tissue and supportive cells.
The tunica intima is surrounded by a thin membrane comprised of
elastic fibers running parallel to the vessel.
Capillaries consist only of the thin endothelial layer of cells with an
associated thin layer of connective tissue.

68. Tunica Media
Surrounding the tunica intima is the tunica media, comprised of smooth
muscle cells and elastic and connective tissues arranged circularly around
the vessel.
This layer is much thicker in arteries than in veins.
Fiber composition also differs; veins contain fewer elastic fibers and
function to control calibre of the arteries, a key step in maintaining blood
pressure.

69. Tunica Externa
The outermost layer is the tunica externa or tunica adventitia,
composed entirely of connective fibers and surrounded by an
external elastic lamina which functions to anchor vessels with
surrounding tissues.
The tunica externa is often thicker in veins to prevent collapse
of the blood vessel and provide protection from damage since
veins may be superficially located.

70. Valve Function
A major structural difference between arteries and veins is
the presence of valves. In arteries, the blood is pumped
under pressure from the heart, so backflow cannot occur.
However, passing through the capillary network results in a
decrease in blood pressure, meaning that backflow of blood
is possible in veins. To counteract this, veins contain
numerous one-direction valves that prevent backflow.

73.  Blood is a fluid connective tissue that consists of a liquid
matrix containing cells and cell fragments. The liquid
matrix is the plasma and the cells and cell fragments are
the formed elements.
The total blood volume in the average adult is about 4–5
litres (l) in females and 5–6 l in males. Blood makes up
about 8% of total body weight.

74. Functions of the blood
 1. Carrier of gases, nutrients, and waste products. Oxygen enters blood in
the lungs and is transported to cells. Carbon dioxide, produced by cells, is
transported in the blood to the lungs, from which it is expelled. Ingested
nutrients, ions, and water are carried by the blood from the digestive tract to
cells, and the waste products of the cells are moved to the kidneys for
elimination.
 2. Clot formation. Clotting proteins help stem blood loss when a blood vessel is
injured.
3. Transport of processed molecules. Most substances are produced in one
part of the body and transported in the blood to another part.

75. 4. Protection against foreign substances. Antibodies help
protect the body from pathogens.
5. Transport of regulatory molecules. Various hormones and
enzymes that regulate body processes are carried from one part
of the body to another within the blood.
6. Maintenance of body temperature. Warm blood is
transported from the inside to the surface of the body, where
heat is released from the blood.
7. pH and osmosis regulation. Albumin is also an important
blood buffer and contributes to the osmotic pressure of blood,
which acts to keep water in the blood stream.

76. Physical Characteristics And Volume
• Blood is a sticky, opaque fluid with a characteristic metallic taste.
• Color: Depending on the amount of oxygen it is carrying, the color of blood
varies from scarlet (oxygen-rich) to a dull red (oxygen-poor).
• Weight: Blood is heavier than water and about five times thicker, or more
viscous, largely because of its formed elements.
• pH: Blood is slightly alkaline, with a ph between 7.35 and 7.45.
• Temperature: Its temperature (38 degrees celsius, or 100.4 degrees
fahrenheit) is always slightly higher than body temperature.

79. PLASMA
• Plasma is referred to as the matrix of blood.
• Blood is primarily composed of RBC (red blood cells), WBC (white
blood cells), blood platelets, plasma and serum. Among these
components, plasma is the main component of blood.
• Plasma can be defined as an extracellular and liquid portion of a
blood, which is transparent and pale yellow or straw-colored.
• Plasma constitutes 50 to 55 percent of total blood volume.
• Plasma in blood cells is rich in proteins, immunoglobulin, clotting
factors and fibrinogen. This protein helps in coagulation factors and
also maintains serum osmotic pressure.

81. Features Of Blood Plasma
• It contains fibrinogen, immunoglobulin, electrolytes and proteins.
• Blood plasma is the main medium for excretory product
transportation.
• Blood plasma has a density of approximately 1025 kg/m3, or 1.025
g/ml.
• Plasma is the medium of the blood, in which different types of blood
cells exist.
• Blood plasma has a long shelf life; therefore, it can be preserved for
more than a year and can be used

82. Blood Cells
• Blood cells, also known as hematocytes, hemocytes, or hematopoietic cells.
• The process of making blood cells is called hematopoiesis. Blood cells are
made in the red bone marrow. That's a spongy tissue located inside some
bones. It contains young parent cells called stem cells.
• Myeloid stem cells develop into red cells and some white cells (neutrophils,
eosinophils, basophils and monocytes) and platelets. Immature myeloid stem
cells are called myeloblasts.
• Lymphoid stem cells develop into t-cells and b-cells. Immature lymphoid stem
cells are called lymphoblasts.

83. These constitute the other half, around 45%. There are three types of cells, namely:
• Erythrocytes or red blood cells ( RBC)
• Leucocytes or white blood cells ( WBC)
• Thrombocytes or platelets

86. Red Blood Cells (Erythrocytes)
• Most abundant cells in the blood
• Account for approximately 40 to 45 percent of the blood.
• Biconcave disc which is round and flat, sort of like a shallow bowl.
• Disk diameter of approximately 6.2-8.2 micrometer.
• They have a thick rim and a thin sunken center.
• Nucleus absent.
• Can change shape without breaking.
• Production of RBCs is controlled by erythropoietin.

87. • RBC contains hemoglobin (33%).
• The iron found in hemoglobin gives the blood its red color.
• RBCs cannot repair themselves.
• Life span of 120 days.
• 4 million new erythrocytes are produced per second in human adults.
• 20–30 trillion red blood cells at any given time.
• Male: 4.3-5.9 million/mm3 and female: 3.5-5.5 million/mm3

88. Functions
• Transport oxygen from the lungs to the cells of the body.
• Pick up carbon dioxide from other tissues and unload it in the lungs.

89. Hemoglobin
• Hemoglobin is formed by the combination of heme with globin (protein).
Hemoglobin is a protein made up of four amino acid chains. Each of these
chains contains heme, a compound that contains iron and transports
oxygen in the bloodstream. The pigment in hemoglobin is responsible for
the red color of blood.
• Hemoglobin forms an unstable reversible bond with oxygen. In the
oxygenated state, it is called oxyhemoglobin and is bright red; in the
reduced state, it is purplish blue.

91. WHITE BLOOD CELLS (WBC) OR
LEUKOCYTES
• White blood cells (WBC) or leukocytes are a heterogeneous group
of nucleated cells that are found in the blood that are primarily
involved in the various activities related to immunity.
• Leukocytes are separated into two major groups; granulocytes
and agranulocytes, based on the density of their cytoplasmic
granules.

93. Granulocytes
• Granulocytes are a group of white blood cells that are characterized
by the presence of cytoplasmic granules.
• All granulocytes are differentiated cells with a life span of only a
few days.
• The cell contains Golgi complexes and rough ER that are poorly
developed, with few mitochondria mainly needed for glycolysis to
meet their energy needs.
• Granulocytes are further divided into eosinophils, neutrophils, and
basophils

94. • Basophils (0.5-1%) : these represent less than 1% of white blood
cells in the body and are typically present in increased numbers after
an allergic reaction.
• Eosinophils (2-4%): these are responsible for responding to
infections that parasites cause. They also play a role in the general
immune response, as well as the inflammatory response, in the body.
• Neutrophils (60-70%): these represent the majority of white blood
cells in the body. They act as scavengers, helping surround and
destroy bacteria and fungi that may be present in the body.

95. Agranulocytes: they are the types of white blood cells, with
the absence of granules in their cytoplasm.

96. LYMPHOCYTES (20-25%)
These white blood cells include the following:
• B cells: also known as B-lymphocytes, these cells produce antibodies
to help the immune system mount a response to infection.
• T cells: also known as T-lymphocytes, these white blood cells help
recognize and remove infection-causing cells.
• Natural killer cells: these cells are responsible for attacking and
killing viral cells, as well as cancer cells.

97. MONOCYTES
• Monocytes are white blood cells that make up around 2–8%
of the total white blood cell count in the body. These are
present when the body fights off chronic infections.
• They target and destroy cells that cause infections.

98. PLATELETS
• Platelets, also called thrombocytes are a component of blood
whose function (along with the coagulation factors ) is to react
to bleeding from blood vessel injury by clumping, thereby
initiating a blood clot.
• Coagulation, also known as clotting, is the process by
which blood changes from a liquid to a gel, forming a blood clot.

99. WHAT IS SERUM ?????
• The clear yellow fluid separated when
blood is allowed to clot freely.
• It is the watery fluid from blood
without the clotting factors.
• The serum contains proteins,
electrolytes, antibodies, antigens, and
hormones.
• The serum contains 90% water.

100. Hemoglobin normal range:
• Male (ages 15+): 13.0 - 17.0 g/dl
• Female (ages 15+): 11.5 - 15.5 g/dl
Hematocrit normal range:
• Male: 40 - 55%
• Female: 36 - 48%
Platelet count normal range:
• Adult: 150,000 - 400,000/ml
White blood cell (WBC) normal range:
• Adult: 5,000-10,000/ml

102. LYMPHATIC SYSTEM
• The lymphatic system is a part of the circulatory system, comprising a
network of conducts called lymphatic vessels that carry a clear fluid called
lymph, uni-directionally towards the heart.
• Some tissue fluid returns to the capillaries at their venous ends and the
remainder diffuses through the more permeable walls of the lymph
capillaries, forming lymph. The cells of the body are bathed in interstitial
fluid which leaks constantly out of the blood stream through the permeable
walls of blood capillaries.
• Some tissue fluid returns to the capillaries at their venous ends and the
remainder diffuses through the more permeable walls of the lymph
capillaries, forming lymph.

103. The lymphatic system has three main functions:
• It maintains the balance of fluid between the blood and tissues, known
as fluid homeostasis.
• It forms part of the body’s immune system and helps defend against
bacteria and other intruders.
• It facilitates absorption of fats and fat-soluble nutrients in the
digestive system.

104. Lymph
• Lymph is a clear colorless watery fluid, similar in composition to
plasma, with the important exception of plasma protein.
• Lymph contains less proteins than blood.
• It is identical in composition to interstitial fluid.
• The hydrostatic pressure of blood in the blood vessel force our water
and small protein into the interstitial space.
• Once carried by the lymphatic capillaries, it is known as lymph.
• Its main function is to nourish and bath tissues.

105. • It transports the plasma protein that sweeps out of the capillary bed
to the blood stream.
• It also carries away larger particles such as bacteria and cell debris
from damaged tissues, which can then be filtered out and destroyed
by the lymph node.
• Lymph consists of lymphocytes, which circulates in the lymphatic
system permitting them to patrol the different regions of the
absorbed into the lymphatics give the lymph, a milky appearance.
• Lymph is the most common route for cancer cell spread (metastasis).
(Second common route is via the blood)

106. Lymphatic system consists of:
• Lymphatic capillaries (lacteals)
• Lymphatic vessels
• Lymph node (lymph gland)
• Lymphoid organs:
• Tonsil
• Spleen
• Thymus gland
• Aggregated payer patches

116. Blood Group System
• Karl landsteiner, an austrian scientist discovered the ABO
blood group system in the year 1900.
• The ABO blood group system consists of 4 types of blood
group – A, B, AB, and O and is mainly based on the antigens
and antibodies on red blood cells and in the plasma.
• Both antigens and antibodies are protein molecules in which
antigens are present on the surface of red blood cells and
antibodies are present in the plasma which is involved in
defending mechanisms.

117. ABO Blood group system
• The basis of ABO grouping is of two antigens- antigen A and
antigen B. The ABO grouping system is classified into four types
based on the presence or absence of antigens on the red blood
cells surface and plasma antibodies.
• GROUP A – Contains antigen A and antibody B.
• GROUP B – Contains antigen B and antibody A.
• GROUP AB – Contains both A and B antigen and no antibodies
(neither A nor B).
• GROUP O – Contains neither A nor B antigen and both antibodies A
and B.

119. Individuals of blood group O are called as universal donors,
whereas individuals of blood group AB are universal
recipients.

120. Rh blood group system
In addition to the ABO blood grouping system, the
other prominent one is the Rh blood group system.
About two-thirds of the population contains the
third antigen on the surface of their red blood cells
known as Rh factor or Rh antigen; this decides
whether the blood group is positive or negative. If
the rh factor is present, an individual is rhesus
positive (Rh+ve); if an rh factor is absent individual
is rhesus negative (Rh-ve) as they produce rh