Health is a state of physical, mental and social well
The conditions necessary for good health are :i) Good physical and social environment.
ii) Good economic conditions.
iii) Social equality and harmony.
Good physical and social environment includes
clean surroundings, good sanitation, proper
garbage disposal and clean drinking water .
Good economic conditions includes job
opportunities for all for earning to have
nutritious food and to lead a healthy life.
Social equality and harmony are necessary for a
healthy and peaceful life.
2) Differences between
Healthy and Disease free :Healthy
It is a state of physical, mental
and social well being.
It is a state of absence from
It refers to the individual,
physical and social
It refers only to the individual.
The individual has good health.
The individual may have good health
or poor health.
When a person is affected by
a disease either the normal
functioning or the appearance
of one or more systems of
the body changes for the
These changes give rise to
signs of the disease called
On the basis of the symptoms
Diseases are of different types. They
diseases which last only
for a short period of time and does not have long term
effect on health.
Eg:- cold, cough, typhoid, cholera etc.
are diseases which lasts
for a long time and
has long term drastic effect
Eg :- diabetes, tuberculosis,
elephantiasis, arthritis, cancer etc.
and disposal of
immunity for 3
It is caused by microbes or micro –organisms
.These diseases can spread in the community .
Infectious diseases are caused by bacteria,
viruses , fungi, and unicellular organisms like
protozoans.Some multicellular organisms like worms
also cause infectious diseases.
Infectious diseases caused by viruses are such as
common cold ,influenza , dengue fever, AIDS etc.
Bacterial diseases of bacteria are typhoid fever ,
cholera, tuberculosis ,anthrax etc.
Common infectious skin diseases are caused by
Protozoan cause diseases such as malaria ,kalaazar .Worms cause intestinal diseases as well as
are not spread to other persons. These
are of following types:Deficiency- caused deficiency of nutrients and
hormones. E.g. diabetes , scurvy.
Allergic – when body is hypersensitive to
foreign elements. E.g. asthma
Cancer- uncontrolled growth of certain tissues.
Mental disorder- depression ,anxiety etc.
Addiction :- alcohol, drugs.
Degenerative- malfunctioning of important
organs .E.g. heart diseases.
Viral :- influenza , chickenpox , small pox ,common cold, dengue
fever and AIDS
Common cold (viral)
cause – Rhino virus
symptoms – sore throat , cough , headache.
Chicken pox (viral)
symptoms – rashes, fever, aches , uneasiness.
symptoms –red and watery eye, pink rashes, itching or
burning or rashes.
Cause- salmonella typhi.
Symptoms- fever ,headache ,loss of appetite, skin rash ,either
constipation or diarrhea.
Cause – Mycobacterium tuberculosis.
Symptoms – night sweats, fatigue, weight loss.
Cause –female anopheles mosquito
Symptoms –fever at interal,weakness .
Cause- abnormal and uncontrolled growth of cells
Risk factors – tobacco, alcohol, high fat diet , smoking.
Cause- blood pressure levels, stress, tension , salt intake ,fat
Picture of Leishmania ,the protozoan organism that causes kala –azar .The
Organisms are oval shaped ,and each has one long whip like structure . One
organism(arrow )is dividing ,while a cell of the immune system (lower right ) has gripped
on the two whips of the dividing organism and is sending cell processes up to eat up the
organism . The immune cell is about ten micrometers in diameter.
Picture of staphylococci ,the bacteria which can cause acne .
Picture of an adult roundworm (Ascaris lumbricoides is the technical name )
From the small intestine .The ruler next to it shows
These categories of infectious agents are
important factors in deciding what kind of
treatment to use .Members of each one of
these groups- viruses, bacteria , and so on –
have many biological characteristics been
An antibiotic is a selective poison. It hasin
common. that it will for the desired bacteria,
chosen so All viruses , kill example ,live inside
host cells ,whereas bacteria very rarely do.
but not the cells in our body. Each different
type of antibiotic affects different bacteria in
different ways. For example, an antibiotic might
inhibit a bacterium's ability to turn glucose into
energy, or its ability to construct its cell wall.
When this happens, the bacterium dies instead of
reproducing. At the same time, the antibiotic
acts only on the bacterium's cell-wall-building
mechanism, not on a normal cell's. Antibiotics
commonly block biochemical pathways
important for bacteria .These inhabit the
growth of bacteria or kill them.
Antibiotics do not work on viruses because
Germs can spread to
the hands by sneezing,
coughing, or rubbing
the eyes and then can
be transferred to other
family members or
washing your hands
can help prevent such
illnesses as the
common cold or eye
Hands to food:
Usually germs are transmitted from
unclean hands to food by an
infected food preparer who didn’t
wash his or her hands after using
the toilet. The germs are then
passed to those who eat the food.
Germs are also transmitted from
raw foods, such as chicken, to
hands while preparing a meal.
Wash your hands after petting animals or
touching any surfaces they come into contact
refers to the transfer of an infectious agent from an infected host to a new host,
without the need for intermediates such as air, food, water or other animals.
Direct modes of transmission can occur in many ways:
Direct projection of droplets
Across the placenta
modes of transmission
Indirect transmission is when infectious
agents are transmitted to new hosts
through intermediates such as air, food,
water, objects or substances in the
environment, or other animals. Indirect
transmission has three subtypes:
The infectious agent
may be transmitted in
dried secretions from
the respiratory tract,
which can remain
suspended in the air for
some time. For
example, the infectious
tuberculosis can enter a
new host through
A vehicle is any non-living substance or
object that can be contaminated by an
infectious agent, which then transmits it to a
new host. Contamination refers to the
presence of an infectious agent in or on the
A vector is an
agent to a new
which act as
Microbes which enter our
body are Likely to go to
different Sites in our body
such as :-
Q1: Which one of the following is an infectious disease?
Q2: Elephantiasis disease can have
(a) short-term affect on our health
(b) no effect on our health
(c) long term affect on our health
(d) sometimes bad effect on our health
1: (a) diphtheria
2: (c) long term affect on our health
Q3: Ascaris worm lives in which part of human body?
(c) small intestine
(d) large intestine
Q4: Microbes which enter the body through nose most likely affect
Q5: Which of the following is a viral infection?
3: (c) small intestine
4: (d) lungs
5: (b) Influenza
Q6: HIV virus when active in body mainly attacks on
Q7: An Organism which carries pathogens is termed as
Q8: Diseases which are always present in certain location are called?
(a) epidemic diseases
(b) endemic diseases
(c) acute diseases
(d) chronic diseases
6: (c) immunity
7: (b) vector
8: (a) epidemic diseases
Q9: DPT vaccines are administered to develop immunity
(d) All of these
Q10: Anti-viral drugs are difficult to make because, viruses
(a) live outside the host cells
(b) live inside the host cells
(c) live in consumed food particles
(d) live in blood stream
Q11: BCG vaccine is used to develop immunity against
9: (d) All of these
10: (a) live outside the host cells
11: (d) tuberculosis
Q12: Which of the following is a communicable disease?
Q13: The causative organism for malaria is a:
Q14: Vaccination helps in controlling diseases because
(a) it develops resistance against the pathogen attack
(b) it kills the pathogens causing disease
(c) it blocks the food supplied to pathogens
(d) it does not allow pathogens to multiply in hosts
12: (d) Cholera
13: (b) protozoa
14: (a) it develops resistance against the
Q15: ORS is given in
Q16: Which of the following is an example of
nutritional deficiency disease?
15: (a) diarrhea
16: (b) Rickets
a) Define disease?
b)What are the two major categories of human diseases. Give
two examples of each ?
Ans a)-Any functional or physical change from the natural state that
cause discomfort or disability is called a disease.
Ans b) The major categories of human diseases are :
Communicable (infectious) diseases
e.g.- Malaria ,jaundice.
Non –communicable (non-infectious)diseases.
e.g.– Cancer, diabetes.
What are the causes of non-infectious diseases?
Ans- These are not spread to other persons and are not caused by any
infection are called non –infectious. Causes arei.
Genetic abnormabilities: Haemophilia, some type of cancers .etc.
Internal causes : Such as high blood pressure can be caused by
excessive weight and lack of
What is infectious disease and their causes?
Ans-These are spread to other person and are caused by microbes are called
They are caused by –
List the causes of diseases .
Lack of proper and sufficient food
Lack of public services
Genetic differences .
List four diseases caused by viruses?
Ans- diseases caused by viruses are –
What are the difference between communicable and non- communicable
NON-COMMUNICABLE (NONINFECTIOUS )DISEASES
They are infectious diseases .They are
transferred from a patient to the healthy
They are not infectious diseases
and cannot be transferred from a
patient to a healthy person.
They are caused by a pathogen (disease
They are not caused by pathogen.
They are spread through some agency
such as air , food , contact ,insects, etc.
They do not spread through any
These are not caused by nutritional
deficiency. These are due to infection.
They are caused by nutritional
deficiency degeneration of organs
or malfunctioning of a vital organ,
not caused by infection.
Explain why antibiotics are more effective in curing bacterial
diseases than viral diseases.
Ans-Antibiotics are effective in curing bacterial and fungal infections (e.g.tuberculosis)but they are ineffective in viral diseases (e.g.-common cold
).Antibiotics affect on life process of bacteria and inhibit their growth
.On the other hand virus is just apiece of DNA (RNA ),not well defined
life form .Viruses can reproduce inside host cells .They do not use
biochemical pathways as used by other microbes (bacteria ,fungi ,
parasites).That's why antibiotic are ineffective in viral infections.
Define antibiotic? Explain how it is able to control bacterial
infections but not viral infections?
Ans-Antibiotics (anti means against , biotic –living) are types of
medications that destroy or slow the growth of bacteria. They are often
termed as antibacterial .They work against the life processes of bacteria
.Many bacteria ,for example ,make a cell-wall to protect themselves .The
antibiotic penicillin blocks the bacterial processes that build the cell wall.
Thus bacteria fail to build their cell –wall, stop multiplying and die out
.Human cells don’t make a cell-wall anyway, so penicillin cannot have
such effect on us.
Give causes and remedy of
i) Hepatitis is caused by virus
ii) AIDS is caused by HIV.
iii) Malaria is caused by
Spread by bite of female
- Hepatitis A and B vaccination
- Avoid eating stale food .
- Avoid any type of infection
- Now anti – viral drugs that keep HIV
infection under control are available .
-Avoid breeding of mosquito in stagnant
water ditches ,ponds,etc.
- Consult doctor for treatment .
-Use mosquito repellents.
What Is Cancer? What Causes Cancer?
ANS-Cancer is a class of diseases characterized by out-of-control cell growth. There are
over 100 different types of cancer, and each is classified by the type of cell that is initially
Cancer harms the body when damaged cells divide uncontrollably to form lumps or
masses of tissue called tumors (except in the case of leukemia where cancer prohibits
normal blood function by abnormal cell division in the blood stream). Tumors can grow
and interfere with the digestive, nervous, and circulatory systems, and they can release
hormones that alter body function. Tumors that stay in one spot and demonstrate
limited growth are generally considered to be benign.
More dangerous, or malignant, tumors form when two things occur:
1.a cancerous cell manages to move throughout the body using the blood or lymph
systems, destroying healthy tissue in a process called invasion
2.that cell manages to divide and grow, making new blood vessels to feed itself in a
process called angiogenesis.
When a tumor successfully spreads to other parts of the body and grows, invading and
destroying other healthy tissues, it is said to have metastasized. This process itself is
called metastasis, and the result is a serious condition that is very difficult to treat.