8-Human Health and Diseases.pptx

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8-Human Health and Diseases
By- Milind A Kherde,
PGT-Biology,
JNV-Washim

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 According to the World Health
Organisation (WHO) health is defined as-
“health is a state of complete physical,
mental and social wellbeing and not
merely an absence of disease or physical
fitness.”
 Healthy people are more efficient at work.
 Thus increasing productivity and
bringing economic prosperity.
 Balance diet, Personal hygiene and
regular exercise are very important to
maintain good health.

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Health is affected by following factors.
1) Genetic disorders: - defects which the
child inherits from parents.
2) Infections,
3) Lifestyle including food and water we
take, rest and exercise, our habits etc.
Disease: - Any condition that interferes
with the normal functioning of the body
and impairs the health is called disease.

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Types of diseases: - The diseases are
broadly grouped into two categories.
1) Congenital diseases: - These diseases
have been present since birth. They are
caused due to genetic abnormality or due
to metabolic disorders or malfunctioning
of any organ or system. Generally they
are not easily curable and maybe
inherited to the children.
2) Acquired diseases: - These diseases
develop after birth. Acquired diseases are
of two types.

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i) Communicable or infectious diseases: -
Diseases which are easily transmitted from
an infected person to the healthy person are
called infectious diseases. Infectious
diseases may be Contagious or non-
contagious.
ii) Non communicable or non-infectious
diseases: -
Diseases which are not transmitted from an
infected person to healthy person are called
non infectious diseases.

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Pathogens: - Disease causing organisms
are called pathogens.
 Bacteria, viruses, fungi, protozoan,
helminths, etc. are the examples of
pathogens.
 All parasites are pathogens as they cause
harm to the host by living in or on them.
 Pathogens enter in our body, multiply
and interfere with normal vital activities,
resulting in morphological and functional
damage.

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 The abnormal changes in the
functioning or appearance of normal body
activities are called disease symptoms.
 Headache,
 coughing,
 loose motion,
 wound with pus,
 inflammation,
 swelling,
 fever, etc. are common symptoms.

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Diseases caused by pathogens: -
Bacterial diseases- Typhoid, pneumonia,
cholera, tetanus, etc.
Viral diseases- common cold, chicken
pox, polio, rabies, AIDS, etc.
Protozoan diseases- malaria, amoebiasis.
Helminth diseases- ascariasis, Filariasis
Fungal diseases- Ringworms.

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Common diseases in humans: -
1) Typhoid (Enteric fever): -
 Typhoid is caused by bacteria
Salmonella typhi.
 It is an acute infection of the intestine.
 These pathogens generally enter the small
intestine through food and water
contaminated with them.
 The common symptoms of typhoid are
headache, high fever, low pulse rate, loss of
appetite, stomach pain, and frequent stools.
 Death may occur in severe cases.

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 Typhoid fever could be confirmed by the
Widal test.
 Relapse is very common in typhoid.
 The patient is treated with antibiotics
such as Terramycin and Chloromycetin.
 Any person carrying typhoid bacteria in
his intestine can spread the disease to
others even though the person himself may
not be suffering from the disease.
 These persons are known as healthy
carriers.

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 The classic case in medicine, that
of Mary Mallon Known as Typhoid
Mary, who was the cook and a
typhoid carrier.
 She gave rise to more than 1300
cases in her lifetime through food she
prepared.

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2) Pneumonia: -
 Pneumonia is caused by bacterium
Streptococcus pneumoniae and
Haemophilus influenzae.
 It is an acute respiratory infection
which affects the alveoli of the lungs.
 As a result of the infection, the alveoli
get filled with fluid leading to severe
problems in respiration.
 Its infection is Airborne.
 Bacterial cysts are spread by sputum
of the patients.

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 The common symptoms of
Pneumonia are fever, chills, cough,
headache, and lips and fingernails may
become Grey to bluish coloured etc.
 Its treatment includes the use of
penicillin, streptomycin and ampicillin.

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3) Common cold: -
 It is one of the most infectious diseases
caused by a group of viruses called
Rhinoviruses.
 The viruses are transmitted through
inhalation of droplets from infected persons.
 They infect the nose and respiratory
passage but not the lungs.
 The common cold is characterised by
nasal congestion, and discharge, sore
throat, hoarseness, cough, headache,
tiredness etc.
 Antibiotics are given for treatment.

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4) Malaria: -
 Malaria is one of the oldest and most
destructive diseases of mankind.
 It is more common in Africa and Asia.
 Malaria is caused by tiny Protozoa a
Plasmodium. Different species of plasmodium
(P. vivax, P. malaria and P. falciparum) are
responsible for different types of Malaria.
 Of these malignant malaria caused by
Plasmodium falciparum is the most serious
and can cause death.
 Malaria is caused by toxic pigment
haemozoin formed from haemoglobin of RBCs
when RBCs are destroyed by plasmodium.

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Symptoms of malaria: -
 The patient shows symptoms of malaria
after a period of 14 days.
 Early symptoms are restlessness,
headache, nausea and muscular pain.
 Next there is shaking chills with rapidly
rising temperature up to 1060 F.
 The patient sweats a lot and the
temperature goes down to normal, till the
next attack after 48 hours.

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Life cycle of Plasmodium: -
 Life cycle of plasmodium requires two
hosts (digenetic) and triphasic
(Sporogony, Schizogony, and Gamogony ).
 Female Anopheles Mosquito is a
primary host and man is secondary host.
 (Sporogony)Plasmodium enters the
human body as sporozoites (infective
stage) through the bite of infected female
Anopheles Mosquito.
 The parasites (sporozoites) reach the
liver through blood where it multiplies
asexually (Schizogony).

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 By bursting liver cells it is released into
the blood where it attacks the red blood cells
and ruptures them.
 The rupture of RBCs releases a toxic
substance haemozoin, which cause chill
and high fever.
 Released parasites infect new blood cells.
 Sexual stage (gametocytes) develops in
red blood cells (Gamogony).
 Female Anopheles Mosquito takes up
gametocytes with blood.
 Fertilisation and development takes place
in the mosquito’s stomach.

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 The zygote elongates and becomes a
motile called ookinete.
 The ookinete bores through the wall of
the stomach and changes to oocyst.
 Inside the oocyst, sporozoites are formed
which are stored in their salivary glands.
 When the female Anopheles Mosquito
bites a healthy person; the sporozoites are
introduced in his/ her body along with
saliva.
 Quinine is a drug used for malaria which
is extracted from the bark of the Cinchona
tree.

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5) Amoebiasis (Amoebic dysentery): -
 Amoebiasis is the condition of harbouring
the protozoan parasite Entamoeba
histolytica in the large intestine of humans.
 It is more commonly found in males than
females.
 The sources of infection are the cysts
from the faeces of the infected persons.
 Contaminated raw vegetables, fruits, and
water transmit the disease.
 House flies, Cockroaches, rodents act as
carriers of the cysts.

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 The symptoms of this disease are mild
diarrhoea alternating with constipation.
 In severe cases there may be dysentery
with mucus and blood in stool and pain in
the abdomen.
 Its treatment includes the use of
metronidazole and tinidazole.

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6) Ascariasis: -
 Ascariasis is an infection of the small
intestine caused by the roundworm, Ascaris
lumbricoides.
 Ascaris lumbricoides is an endoparasite
which is elongated, cylindrical and tapering
at both ends.
 It is more common in children because
children are having the habit of eating soil
and clay.
 In human infection is direct and oral with
contaminated food and water.
 Flies and Cockroaches are passive vectors.

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The symptoms of ascariasis are internal
bleeding, muscular pain, fever, anaemia and
blockage of the intestinal passage.
In children where infection is more
common, show dull mental capacity and
stunt growth.
The eggs of the parasite are excreted
along with the faeces of infected people which
contaminate soil, water, vegetables etc.

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7) Elephantiasis or Filariasis: -
 Filariasis is caused by Wuchereria
bancrofti and W. malayi, commonly called
filarial worms.
 The adult worm lives in the lymphatic
vessels and lymph glands, especially of
lower limbs.
 Life history of filarial worm is digenetic.
 It is a viviparous worm.
 The mature female gives birth to
juveniles known as microfilariae.
 The microfilariae pass into blood vessels
from the lymphatic system.

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 The microfilariae will develop further
when they are sucked up along with human
blood by mosquitoes.
 The female Culex mosquito is an
intermediate host.
 Infection is transmitted by infected
female Culex mosquitoes.
 Filariasis is characterised by the
inflammation of lymph glands usually of the
lower limbs results in elephantiasis or filariasis.
 This is due to excessive growth of
connective tissue and enormous swelling in the
arms, legs, scrotum, breasts, etc.

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8) Ringworms:
 It is one of the most infectious diseases in
man.
 It is caused by fungi with genera like
Microsporum, Trichophyton, and
Epidermophyton.
 In human infection occurs either through
contact with infected persons or from soil or
through the towels, clothes, comb etc. of the
infected person.
 These are characterised by dry and scaly
lesions on skin, nails, scalp, etc. of the
body accompanied with severe itching.

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 Growth of fungus and spread of
ringworm is favoured by heat and moisture.
 Antibiotics are
recommended for
treatment.

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9) Chikungunya: -
 It is caused by Chikungunya virus.
 Its transmission takes place by the bite
of Aedes aegypti mosquito.
 No vaccine is available.
 Its symptoms are sudden onset of fever,
crippling joint pain, lymphadenopathy and
conjunctivitis.
 Paracetamol is given to reduce fever and
drugs such as aspirin for the joint pain.

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10) Dengue Fever: -
 Dengue fever is caused by flavi- ribovirus
and is transmitted by the bite of Aedes aegypti
female mosquitoes.
 Two types of dengue fever are common-
classical dengue fever and dengue
haemorrhagic.
 Symptoms of classical dengue fever are high
fever, Headache, muscular and joint pains, loss
of taste and appetite, nausea and vomiting.
 In haemorrhagic fever bleeding from the
nose, mouth, gums and skin, severe stomach
pain, frequent vomiting etc.
 No specific treatment is available.

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Prevention and control of diseases: -
Measures for personal hygiene.
 Measures for prevention and control of
diseases include keeping the body clean,
consumption of clean drinking water, food,
vegetables, fruits, etc.
 For public hygiene the important things
are proper disposal of waste and excreta,
periodic cleaning and disinfection of
water reservoirs, pools and tanks.
 To prevent airborne diseases such as
pneumonia and common cold one should avoid
close contact with the infected persons and
their belongings.

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 To prevent malaria and filariasis we
have to eliminate the vectors and their
breeding places.
 We have to avoid stagnation of water
around residential areas.
 Use of mosquito net, spraying
insecticides and introducing fishes like
Gambusia in ponds is also helpful to control
mosquitoes.
 Infectious diseases like polio, diphtheria,
pneumonia and tetanus have been
controlled to a large extent by the use of
vaccines.

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Immunity: -
The overall ability of the host body to
protect from all types of foreign bodies like
bacteria, viruses, toxic substances etc. with
the help of the immune system is called
immunity.
 The infected person with no disease is
called immune.
The immune system can differentiate
between self (own cells) and non self.
Any foreign substance or pathogen that
enters the body is called antigen.

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The protective chemicals produced by
the body in response to antigens are
called antibodies.
Antibodies are a group of proteins
called immunoglobulin.
The antibodies are antigen-specific.
Majority of antigens are proteins or
polysaccharides found on the cell walls
of bacteria and other cells.

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Types Of Immunity-
1) Innate immunity and
2) Acquired immunity.
1) Innate immunity: -
 Innate immunity is nonspecific and is
present at the time of birth.
 It is inherited by the organism from the
parents and protects it from birth
throughout life.
 This is accomplished by providing
different types of barriers to the entry of the
foreign agents into our body.
 Innate immunity consists of four types
of barriers.

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i) Physical barriers: -
 The intact skin is the main barrier which
prevents entry of the microorganisms.
 The mucus coating of the epithelium
lining the respiratory, gastrointestinal, and
urogenital tracts traps the microorganisms
entering our body.

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ii) Physiological barriers: -
 Body temperature, pH of the body
fluids and various body secretions
prevents growth of many diseases causing
microorganisms.
 Acid in the stomach, saliva in the
mouth, tears from Eyes, bile produced by
liver, ear wax, vaginal secretions, all they
prevent the growth of microorganisms.

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iii) Cellular barriers: - Certain types of
leukocytes (WBC) of our body like
poly morpho-nuclear leukocytes (PMNL -
neutrophils), monocytes, and natural killer
in the blood as well as macrophages in
tissue can phagocytose and destroy
microorganisms.
iv) Cytokine barriers: - Virus infected
cells secrete proteins called interferon
which protect non- infected cells form viral
infection.

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2) Acquired immunity: -
The immunity that an individual
acquired during life is called acquired
immunity or adaptive immunity.
Acquired immunity is characterised by
memory.
Acquired immunity is pathogen specific.
When the immune system of our body
encounters a pathogen for the first time, it
produces an immune response called
primary response or first encounter.
The immune system retains the memory
of the first encounter.

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Second encounter occurs more quickly and
highly intensified than the first encounter
and is called secondary response.
The primary and secondary immune
responses are carried out with the help of
immunologically active cells called
lymphocytes.
These are formed by the liver and spleen in
the foetus and by the bone marrow and
lymph nodes in adults.

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There are two types of lymphocytes-
i) T-Lymphocytes and
ii) B- lymphocytes.
 About 75% of lymphocytes are T-cells.
 Both types of lymphocytes are formed
from the stem cells in the bone marrow of
an adult person.
 Both types of lymphocytes need
stimulation by specific antigen but their
mode of response is different.

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a) Mode of action of B- lymphocytes: -
(B for bone derived)
Once B- lymphocytes are stimulated by
an antigen they produce a group of plasma
cells called clones.
 These plasma cells produce antibodies at
a high rate of about 2000 molecules per
second.
These antibodies circulate in the lymph to
fight the antigen.

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This antibody mediated immunity where
antibodies are found in lymph and blood is
called the humoral immune system.
The B- Lymphocytes are short lived and
replaced by new cells after every few days.
Different types of antibodies
are produced in our body with different
immunoglobulin. These are IgA, IgM,
IgE, IgD and IgG. Out of these IgG is most
abundant (80%) in man.

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Structure of an antibody molecule: -
Each antibody is a Y shaped tetrapeptide
protein formed of two identical light chains
and two identical heavy chains.
So and antibody is
represented as H2L2.
Two light chains and
two heavy chains are
interlinked through
-S-S (disulfide) bonds.
Light chains are
small and heavy
chains are longer.

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Heavy and light chains may be either
Lambda or Kappa type. There are five heavy
chain isotypes (IgM, IgD, IgG, IgE, and IgA),
which confer different antibody functions,
and two light chain isotypes (kappa and
lambda).
Heavy chain has two
parts- Variable region
and Constant region.
Variable region of the
antibody has an antigen
binding site bind
antigen and form
antigen- antibody
complex.

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b) Mode of action of T- lymphocytes:
(T-for thymus derived)
T-Lymphocytes mature in the thymus, thus
this immunity is called T- cell immunity.
The T- lymphocytes mediate the cell
mediated immunity (CMI).
During transplantation of human organs
like heart, eye, liver, kidney etc. tissue
matching, blood group matching, etc are
important because the body is able to
differentiate self and nonself with the help of
cell mediated immunity.

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T-cells respond to antigens by
producing clones of T-cells.
Normally T-cells remain alive for 4-5
years.
The clones of the T-cells are similar but
they perform different functions

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T-cells are of following types according to
their functions.
i) Killer T- cells or cytotoxic T-cells: -
These cells directly attack and destroy
antigens.
They migrate to the site of infection and
release lymphokines, lymphotoxin
and interferon. So the phagocytic activity
is enhanced at the site of infection.
These also killed the cancer cells.
ii) Helper T-cells: -
They secrete helper factors which stimulate
B-cells to produce more antibodies and
enhance the activity of Killer T-cells.

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iii) Suppressor T-cells: -
They secrete suppressive factors which
suppress the whole immune system to
protect own body cells from its attack,
called immune tolerance.
Some of these change into memory cells
and get stored in spleen and lymph nodes
to produce antibodies spontaneously
against the same antigen enter the body.

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Types of acquired immunity: - Acquired
immunity is of two types-
Active immunity and Passive immunity.
Active Immunity: -When a host is exposed
to antigens in the form of living or dead
microbes or other proteins, antibodies are
produced in the host body. This type of
immunity is called active immunity.
 It is slow and takes time to give its full
effective response.
 It is long lasting and is harmless.
 During immunisation or during natural
infection active immunity gets produced.
 Active immunity may be natural or artificial.

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ii) Passive immunity: -
 When readymade antibodies are directly
given to protect the body against foreign
agents, it is called passive immunity.
 It provides immediate relief.
 It is not long lasting.
 The yellowish fluid colostrum secreted by
mother during the initial days of lactation
has abundant antibodies (IgA) to protect the
infant.
 The foetus also receives some antibodies
from their mother through the placenta
during pregnancy.
 These are examples of passive immunity.

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Vaccination and immunisation: -
Vaccine is a suspension or extract of dead
or weakened pathogens of disease which on
injection into a healthy person provides
temporary or permanent immunity against
that disease.
 The principle of immunisation or
vaccination is based on the property of
memory of the immune system.
The vaccines also generate memory B and
T- cells that recognise the pathogen quickly.

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Usually two or three injections are needed to
achieve full immunity against a specific
pathogen. The doses given later are
called booster doses.
If a person is infected with some deadly
microbes to which quick immune response is
required as in tetanus or Snake bites, we
need to directly inject the preformed
antibodies or anti toxin. This type of
immunisation is called passive
immunisation.

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The process of the introduction of
vaccines into an individual to provide
protection against a disease is called
vaccination.
In vaccination, antigenic proteins
of pathogens or weakened pathogens are
introduced into the body.
These antigens generate the primary
immune response and the memory B and
T cells.

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 Vaccination and immunisation are two
different processes. Vaccination is the only
administration of a vaccine or toxoid,
while immunisation is the process by
which the body produces antibodies against
the diseases.
 With the help of Recombinant DNA
technology it is possible to produce
antigenic polypeptides of pathogens in
bacteria or yeast.
 Vaccines produced using this approach
is now being used for immunisation,
ex. Hepatitis- B vaccine produced from
yeast.

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Allergies: -
The exaggerated response of the immune
system to certain antigens present in the
environment is called allergies.
The substances to which allergy response is
produced are called allergens.
Antibodies produced to these are of IgE type.
Common examples of allergens are dust,
Pollens, animal dander, Spores, foods, heat, etc.
The symptoms of allergic reaction are sneezing,
watery eyes, running nose, difficulty in
breathing, itching, skin rash etc.
Allergy is due to the release of chemicals like
histamine and serotonin from the mast cells.

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Autoimmunity: -In this immune disorder
when the immune system of an individual fails
to recognise “self” from “nonself” and starts
destroying its own body cells.
This leads to some diseases called
autoimmune diseases.
These may be due to genetic or some other
causes.
The body cells acting as antigens or
nonself are called autoantigens.
Autoimmune disorders occur more in women
than in men.
Rheumatoid arthritis is an autoimmune
disease.

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If the autoantigens are RBCs, then the
lymphocytes of the immune system start
destroying their own RBCs and cause
chronic anaemia.
If the autoantigens are muscle cells, it
destroys own muscle cells and causes
Myasthenia gravis.
If the autoantigens are the liver cells then
it destroys its own liver cells causing
chronic hepatitis.
Other common autoimmune diseases are
insulin- dependent diabetes, multiple
sclerosis, Addison's disease, Hoshimoto
disease, etc.

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Immune system in the body: -
The human immune system consists
of lymphoid organs, tissue, cells and
soluble molecules like antibodies.
Lymphoid organs: -
Lymphoid organs are those organs
where the maturation and
proliferation of lymphocytes takes
place.
Lymphoid organs are of two types.
1) Primary lymphoid organs,
2) Secondary lymphoid organs.

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Bone marrow and thymus are primary
lymphoid organs.
Bone marrow is the main lymphoid organ
where all blood cells including lymphocytes
are formed.
B- Lymphocytes mature in bone marrow.
T- Lymphocytes mature in thymus.
Thymus is situated near the heart.
The thymus is quite large at the time of
birth but keeps reducing in size with
age and by the time puberty it is reduced
to a very small size.

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Secondary lymphoid organs are spleen,
lymph nodes, tonsils, peyer's patches of the
small intestine and appendix.
 The secondary lymphoid organs provide the
sites for interaction of lymphocytes with the
antigen, which then proliferate to become
effector cells.
The spleen is a large bean shaped organ
present just behind the stomach.
It acts as a filter of the blood by trapping
blood-borne microorganisms.
Spleen also acts as blood bank because it
stores both RBCs and WBCs.
It is also called as graveyard of RBCs as it is
site of haemolysis of dead RBCs.

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Lymph nodes are small solid structures
located different points along the
lymphatic system.
Lymph nodes trap microorganisms or
other antigens.
Antigens trapped in the lymph nodes
are responsible for the activation of
lymphocytes.
Lymph nodes are mainly present in the
neck, axilla, Thorax, abdomen, and
groin.

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Lymphoid tissue located within the lining
of the major tracts (respiratory, digestive
and urogenital tracts) is called mucosal-
associated lymphoid tissue (MALT).
It constitutes about 50% of the lymphoid
tissue in human body.
Tonsils are masses of lymphoid tissue
present at pharynx, posterior to tongue.
Peyer’s patches are clusters of lymph nodes
found in the small intestine along the ileum.

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AIDS: -
The word AIDS stands for Acquired
Immuno Deficiency Syndrome.
AIDS was first reported in 1981 in the USA.
In India AIDS was reported in 1986 in
Tamilnadu.
Africa is considered the World AIDS capital.
 AIDS is caused by the Human
Immunodeficiency Virus (HIV), a member of
a group of viruses called retrovirus.
HIV has a protein capsule.
The genome is diploid, composed of two
identical single stranded RNA molecules.

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The virus mostly found in blood, semen
and cerebrospinal fluid.
 After getting into the body of the person,
the virus enters into macrophages where the
RNA genome of the virus replicates to form
viral DNA with the help of the enzyme
reverse transcriptase.
This viral DNA gets incorporated into host
cell’s DNA and directs the infected cells
to produce viruses and in this way acts like
a HIV factory.
Simultaneously HIV enters into helper
T- lymphocytes where it replicates and
produces progeny viruses.

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The progeny viruses released in the blood
attack other helper T- lymphocytes.
Due to the decrease in the number of helper
T- lymphocytes, the person starts suffering
from infections.
During this period, the infected
person suffers from fever, diarrhoea, and
weight loss.
The patient becomes so immuno deficient
that he is unable to protect himself against
these infections.
This last stage of HIV infection is known as
AIDS.

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Mode of transmission: - Transmission
of HIV infection takes place by following
ways.
i) Sexual contact with infected persons.
ii) By transfusion of contaminated blood
and blood products.
iii) By sharing infected needles.
iv) From infected mother to her child
through placenta.
Diagnostic test: - A widely used diagnostic
test for AIDS is Enzyme-Linked Immuno-
Sorbent Assay (ELISA). The confirmatory
test is a “Western Blot” which is a highly
specific test.

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Prevention of AIDS: - National AIDS Control
Organisation (NACO) and WHO has started a
number of programmes to prevent the spreading
of HIV infection. The following steps are helpful
to prevent AIDS.
i) People, particularly the age of 20-49 years
should be educated about AIDS transmission.
ii) Disposable syringes and needles should used.
iii) Following safe sex and regular check up by
HIV susceptible population.
iv) Before transfusion of blood, it should be made
sure that it is free from HIV by the blood bank.
v) High risk groups should refrain from blood
donation.

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Cancer: -
Cancer is uncontrolled proliferation of cells
without any differentiation.
Cancer cells are different from normal cells
in some aspects.
Normal cells have a limited life span.
They are usually replaced by new cells
through cell division and cell differentiation.
Normal cells show a property called
contact inhibition. Due to this property
they contact other cells that inhibit their
uncontrolled growth.

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Cancer cells appear to have lost this
property.
As a result of this, cancerous cells just
continue to divide giving rise to masses of
cells called tumour or neoplasm.
However all tumours are not cancerous.
No tumour is formed in leukaemia (blood
cancer).
Tumours are of two types- i) Benign and
ii) Malignant.
i) Benign tumours: - It remains confined to
the site of its origin and does not spread to
other parts of the body. It causes little
damage to the body. It is non-cancerous.

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ii) Malignant tumours: - It first grows
slowly and shows no symptoms. This stage is
called the latent stage.
 Later these cells grow very rapidly,
invading and damaging the surrounding
normal tissues.
As these cells actively divide and grow they
also starve the normal cells.
At the last stage tumour breaks and its
cells migrate to other parts of the body
through blood and wherever they get lodged
they start a new tumour there. This property
is called metastasis.
This is the most dangerous property of
malignant tumours.

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Types of cancer: -Cancers are classified
on the basis of the tissue from where they
are formed.
Cancers are of three main types.
1.Carcinomas: - This type is mainly
derived from epithelial cells and includes
cervical cancer, breast cancer, skin
cancer, brain cancer, lung cancer,
stomach cancer, etc. about 80% of all
tumours are carcinomas.

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2.Sarcomas: - This time is mainly
located in connective and muscular
tissues and includes the cancer of bones,
cartilages, tendons, adipose tissue,
lymphoid tissue and muscles.
3.Leukaemia: - In this type there is
abnormal increase in white blood
corpuscles and commonly called blood
cancer.

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Causes of cancer: - Study of Cancer cells is
called Oncology.
It is not very clear as to how cancer is caused.
Several factors are now known that are
causing cancer. These factors are
called carcinogens.
Carcinogenic factors are physical, chemical
and biological.
 Ionising radiation like X-rays and gamma
rays and non ionising radiations like U.V.
cause DNA damage leading to neoplastic
transformation.
Tobacco smoking is a cause for lung cancer.
Chewing beetles cause mouth cancer.

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Various Chemicals like nicotine present in
tobacco, caffeine, polycyclic hydrocarbons,
ions of heavy metals, product of combustion of
coal and oil, pesticides, weedicides, some sex
hormones, steroids etc. are also carcinogenic.
Cancer causing viruses are called oncogenic
viruses.
These are having genes called viral
oncogenes.
Several genes called Cellular oncogenes or
proto-oncogenes are present in normal cells
which when activated under certain
conditions cause oncogenic
transformation of the cells.

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Detection and diagnosis of cancer: -
Cancer detection is based on biopsy and
histopathological studies of the tissue. Blood
and bone marrow tests for leukaemia.
In biopsy, a piece of the suspected tissue
examined under microscope
(histopathological studies) by a pathologist.
Techniques like radiography (use of X rays),
CT (computed tomography) and MRI
(magnetic resonance imaging) are very useful
to detect cancers of the internal organs.
Mammography Mammography is
specialized medical imaging that uses a low-
dose x-ray system to see inside the breasts.

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Possible symptoms of cancer: -
i) A persistent cough or hoarseness.
ii) A persistent change in digestive and
bowel habits.
iii) A change in wart or mole.
iv) A lump or hard area in the breast.
v) Unexplained low grade fever.
vi) Unexplained loss of weight.
vii) Any incurable ulcer.
viii) Bleeding in vagina at times other than
menstruation.
ix) Blood loss from any natural orifice or
body openings.

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Treatment of cancer: - Treatment of
cancer consists of different therapies
which are as follows.
1) Surgery: - In surgery, the entire
cancerous tissues are removed
surgically. It has limited utility.
2) Radiation Therapy: - It involves the
exposure of the cancerous parts of the
body to the rays from radioactive
materials, such as Radon, Cobalt,
Iridium, and Iodine. These rays destroy
the cancerous tissue without harming
the surrounding tissue.

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3) Chemotherapy: -
 It involves the administration of certain
anticancer drugs.
 These drugs check cell division by
inhibiting DNA synthesis.
 These drugs may be more toxic to
cancerous cells than to normal cells.
 Thus chemotherapeutic drugs kill
cancerous cells.
 Chemotherapy has side effects like hair
loss, anaemia etc. which get corrected after
the treatment is stopped.

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Drugs and alcohol abuse: -
Drugs which are commonly abused are
Opioids, cannabinoids, and coca
alkaloids.
These are mainly obtained from
flowering plants.
Some of them are obtained from fungi.
4) Immunotherapy: - Patients are given
substances called biological response
modifiers such as γ(gamma)-interferon which
activate their immune system and help in
destroying the tumour.

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Opioids: -
Opioids are the drugs, which bind to
specific Opioid receptors present in our
central nervous system and gastrointestinal
tract.
Opium is extracted from the unripe
capsules of poppy plants Papaver
somniferum.
It is either taken orally or smoked.
Morphine is used to reduce the pain.
Codeine is an ingredient in cough syrups.

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Heroin, commonly called smack is
chemically diacetylmorphine which is a
white, odourless, bitter, crystalline
compound.
The derivatives of opium reduce the
respiratory and cardiovascular activity,
constricts the pupil of eyes, cause nausea
and vomiting.
An overdose leads to respiratory arrest
and death.

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Cannabinoids: -
Cannabinoids are a group of chemicals
which interact with cannabinoid receptors
present in the brain.
 Natural cannabinoids are obtained from the
inflorescence of the plant Cannabis sativa.
Bhang, Ganja and Charas are three drugs
which are obtained from the dried leaves
and flowers of hemp plants, Cannabis indica.
Generally taken by inhalation and oral
ingestion.
Usually mixed with tobacco and smoked.
Their effects are on the cardiovascular
system of the body.

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Coca alkaloid or Cocaine: -
It is obtained from coca plant Erythroxylum
coca.
Cocaine commonly called coke or crack is a
narcotic drug.
It has a stimulating action on the central
nervous system and a feeling of pleasure.
The bad effects are lack of sleep, loss of
appetite and hallucination which ultimately
damage mental function and Insanity.
 Other well known plants with hallucinogenic
properties are Atropa belladonna and Datura.
These days cannabinoids are also being abused
by some sportspersons.

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Drugs like barbiturates, amphetamines,
benzodiazepines, lysergic acid diethyl
amides (LSD) and other similar drugs are
often abused. Morphine is a very effective
sedative and painkiller at is very useful
in patients who have undergone surgery.
A large number of people used tobacco
in the form of smoking, chewing and as a
snuff.
Tobacco contains a large number of
chemical substances including nicotine.

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Nicotine stimulates adrenal gland to
release adrenaline into blood circulation.
It raises blood pressure and increases
heart rate.
Smoking increases the chances of lung
cancer, urinary bladder and throat cancer,
bronchitis, coronary heart disease, gastric
ulcer etc.
 Tobacco chewing increases the risk of
oral cancer.
 In pregnant women, nicotine causes
retardation to the growth of the developing
embryo.

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Adolescence and Drug / Alcohol Abuse: -
Adolescence means both a period and
process during which a child becomes
mature in terms of his / her attitudes and
beliefs for effective participation in society.
The period between 12- 18 years of age is a
period of adolescence.
During adolescence many biological and
behavioural changes take place.

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The reasons for drinking alcohol or
taking alcohol are as follows.
Curiosity, need for adventure and
excitement, experimentation, peer group
pressure, family history etc.
Unstable or unsupportive family
structure is also responsible for drug
and alcohol abuse.

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Addiction and dependence: -
Addiction is the habitual, physiological and
psychological dependence on substance or
practice which is beyond the control of an
individual.
A person who is habitual to a substance or
practice which is harmful is called an addict.
Addiction is a chronic, progressive, and fatal
disorder.

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Drugs are chemical substances used to
treat, prevent and cure diseases.
But when drugs are taken for a purpose
other than their clinical use it forms drug
abuse.
With repeated use of drugs, the tolerance
level of the receptors present in our body
increases.

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If a drug dependent person stop taking
a drug his body stops functioning
normally and he feels severe physical and
psychological disturbances called
withdrawal symptoms.
These may be anxiety, shakiness,
nausea, and sweating.

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Effects of Drug / Alcohol abuse: -
The immediate adverse effect of drugs
and alcohol abuse are in the form of
reckless behaviour, vandalism, and
violence.
Excessive doses of drugs may cause
coma and death due to respiratory failure,
heart failure or cerebral haemorrhage.
Those who take drugs intravenously are
much more likely to get infected by AIDS
and Hepatitis- B.

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Sportspersons are doing misuse of drugs to
enhance their performance.
They misuse narcotic analgesics, anabolic
steroids, diuretics and certain hormones in
sports to increase muscle strength and to
promote aggressiveness and to increase
athletic performance.
The side effects of the use of anabolic steroids
in females are masculinisation, increased
aggressiveness, mood swings, depression,
abnormal menstrual cycles, excessive hair
growth on their face and body, enlargement of
clitoris, deepening of voice.

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Prevention and control: -
1.Avoid undue peer pressure
2. Education and Counselling
3. Seeking help from parents and peers
4. Looking for danger signs
5. Seeking professional and medical
help
In males it induces acne, increased
aggressiveness, mood swings, depression,
reduction of size of testes, decreased sperm
production, breast enlargement, premature
baldness, enlargement of the prostate
gland.

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