A brief introduction to human health and diseases according to ICSE syllabus

1. Human Health and
Diseases
By:- Binkal Thakur
Lecturer Biology
Mount Carmel School
Palampur
By:- Binkal Thakur
Lecturer Biology
Mount Carmel School
Palampur

2. Types of Immune Systems
 Immune system is of two types:
 1. Humoral or Antibody-mediated
immune system (AMIS)
 2. Cell-mediated immune system

3. 1. Humoral or Antibody-mediated
immune system (AMIS)
It is formed of antibodies
which are produced by B
lymphocytes and circulate in
blood plasma and lymph.
◦ Immuno-competent B
lymphocytes, each programmed
to recognise one particular
antigen only.

4. 2. Cell-mediated immune system
(CIMS)
 It is formed by T-lymphocytes, which
directly attack the pathogenic micro-
organisms that has entered the host’s body
or allograft.
 So increase the chances of rejection of
transplanted organs.

5. Antibodies
 These are specific proteins
synthesized by B-lymphocytes in
response to antigen.
 All antibody molecules are
immunoglobulins (Ig, γ globulins) and
are released from plasma cells.
 Immunoglobulins are of five types –
IgG, IgM, IgA, IgD and IgE.

6.  IgG : it is most abundant immunoglobulin in
serum.
 This immunoglobulin is transferred from mother
to foetus through placenta.
 IgA : it is found in saliva, tears, colostrum, etc.
 It is the first antibody formed inside human
body at about the age of 4 months.
 IgE : it is found in mast cells of tissues and
serum and present in least amount.
 It mediates allergic reactions.

7. Basic structure of IgG
IgG has Y- shaped structure formed of
2 identical light chains and 2 identical
heavy chains(H2L2).
Light chain : each light chain is formed
of 214 amino acids and each light
chain has two regions(variable and
constant region).
Each light chain has two inter-chain
disulphide loops; one in variable
region and one in constant region.

8.  Heavy Chain : each heavy chain is
forme of 440 amino acids and each
heavy chain has two regions(variable
and constant region).
 Each heavy chain has four inter-chain
disulphide loops; one in variable
region and three in constant region.

9. Variabl
e
Region
Constant region of
light and heavy
chain
(IgG
)

10. Autoimmunity
 Autoimmunity is the system of immune
responses of an organism against its own
healthy cells and tissues. Any disease that
results from such an aberrant immune
response is termed an "autoimmune disease".
 Prominent examples include diabetes
mellitus type 1, Hashimoto's thyroiditis,
Addison's disease, rheumatoid arthritis (RA).
 Autoimmune diseases are very often treated
with steroids.

11. Allergies
 Allergies are a number of conditions
caused by hypersensitivity of the
immune system to typically harmless
substances (Allergen) in the
environment.
 These diseases include hay fever, food
allergies, atopic dermatitis, allergic
asthma, and anaphylaxis.
 Symptoms may include red eyes, an
itchy rash, sneezing, a runny nose,
shortness of breath, or swelling. Food
intolerances and food poisoning are

12. Acquired Immuno-Deficiency Syndrome
(AIDS)
 AIDS is a spectrum of conditions
caused by infection with the human
immunodeficiency virus (HIV).
 HIV is a retrovirus that primarily infects
components of the human immune
system such as CD4+ T cells,
macrophages and dendritic cells. It
directly and indirectly destroys CD4+ T
cells.

13. Modes of Transmission
 HIV is transmitted by three main
routes:
 sexual contact,
 significant exposure to infected body
fluids or tissues,
 and from mother to child during
pregnancy, delivery, or breastfeeding.

14. Diagnosis
 AIDS can be diagnose by ELISA test
and Western Blot test. These tests
give results only 2 to 24 weeks after
the infection.

15. Symptoms
 Symptoms that you may have during this
time can include:
 weight loss
 chronic diarrhoea
 night sweats
 a fever
 a persistent cough
 mouth and skin problems
 regular infections
 serious illnesses or diseases.

16. Replication Of Retrovirus In The
Infected Human Cell

18. Preventive Measures
 Get tested and know your partner’s HIV status. Talk to
your partner about HIV testing and get tested before you have
sex.
 Have less risky sex. HIV is mainly spread by having anal or
vaginal sex without a condom or without taking medicines to
prevent or treat HIV.
 Use condoms. Use a condom correctly every time you have
sex. Read this fact sheet from CDC on how to use condoms
correctly.
 Limit your number of sexual partners. The more partners
you have, the more likely you are to have a partner with HIV
whose HIV is not well controlled or to have a partner with a
sexually transmitted disease (STD).
 Don’t inject drugs. But if you do, use only sterile drug
injection equipment and water and never share your
equipment with others.

19. Addiction
 Addiction is the physical and mental
dependence on a specific substance
and the person who is unable to resist
is called an addict.

20. Alcoholism
 Regular consumption of alcohol either
in low concentration or in high
concentration causes dependency on
alcohol is called alcoholism.

21. Reason For Alcohol Abuse In
Adolescents
 Social pressure e.g. peer pressure.
 Curiosity, need for adventure and
excitement and experimentation.
 Liking of taste.
 Desire to escape from depression and
frustration.
 Desire to overcome the hardship of daily
life
 False belief of enhanced physical,
mental and intellectual performance.

22. Effects Of Alcoholism On
Health
 Digestive and endocrine glands :
Drinking too much alcohol can cause
abnormal activation of digestive
enzymes produced by the pancreas.
 Liver disease is life-threatening and
leads to toxins and waste build up in
your body.
 Drinking also makes it difficult for your
brain to create long-term memories. It
also reduces your ability to think
clearly and make rational choices.

23.  Circulatory system complications
include:
 high blood pressure, irregular heart
beat, difficulty pumping blood through
the body, heart attack, heart disease,
heart failure.

24. Symptoms Of Alcohol
Withdrawal Include:
 anxiety
 nervousness
 nausea
 tremors
 high blood pressure
 irregular heartbeat
 heavy sweating

25. Drug Addiction
 The habitual non-medical use of
certain drugs forms a habit and one
becomes drug dependent. This is
called drug dependency or drug
addiction or drug abuse.

26. Types Of Drugs
 Drugs can be classified in four
categories on the basis of their mode
of action on brain:
 Seductive and tranquillisers.
 Opioids or narcotics.
 Stimulants.
 Hallucinogens.

27. Effects of Seductive And
Tranquillisers
 They give the feeling of calmness,
relaxation or drowsiness in body.
 Tranquillisers lower tension and
anxiety without inducing sleep.
 Tranquillisers slow down higher
centres of brain and relieve from
worries but do not affect the working
efficiency e.g. Reserpine. So are
normally used as medicines to help
patients suffering from depression and
insomnia.

28. Examples
 Reserpine(drug derived from the roots of
certain species of the tropical plant
Rauwolfia).
 Barbiturates (synthetic sedative from
barbituric acid and called sleeping pills).

29. Effects of Opioids Or
Narcotics
 These act as depressant and
analgesic so are commonly called
pain killers.
 These drugs reduces pain, tension,
anxiety, blood pressure and
respiration rate.
 There overdose causes hypotension,
pinpoint pupil and delayed reflexes.
 In severe cases it may block
respiration and cause death.

30. Examples
 Opium : obtained from Papaver
somniferum.
 Morphine (C17H19O3N) is also a derivative
of Opium.
 Heroin (diacetyle-morphine) commonly
known as smack or brown sugar or
dynamite, is formed from morphine by
acetylation.

31. Effects of Stimulants
 These induce excitement, increased
self confidence, increased alertness,
loss of appetite, etc.
 It also cause hypertension, sweating,
vomiting, etc.

32. Examples
 Caffeine: it is a alkaloid derived from the
seeds of Coffea arabica, leaves of Thea
sinensis and sees of Theobroma cacao.
 Cocaine or coca alkaloids: obtained from
leaves and young branches of South
American plant Erythroxylon coca found
in Bolivia and Peru.

33. Effects Of Hallucinogens
 These cause hallucination (seeing
objects which are not present),
nightmare, photophobia, dilate the
pupil and increased frequency of
urination.

34. Examples
 Lysergic acid diethylamide : obtained
from Ergot fungus( Claviceps purpurea)
 Cannabinoids : obtained from Cannabis
indica, C. sativa

35. Preventive Measures Against
Alcohol/ Drug Abuse
 Avoid undue peer pressure.
 Adolescents should be educated and
properly counselled to accept failures
as a part of life.
 Channelizing their energy into healthy
activities.
 Addicts can be rehabilitated by
seeking professional and medical
help.

36. Cancer
 Cancer is a group of diseases
involving abnormal cell growth with the
potential to invade or spread to other
parts of the body.

37. Characteristics of Cancer
Cells
 Self-sufficiency in growth signals: cancer cells acquire an
autonomous drive to proliferate - pathological mitosis - by
virtue of the activation of oncogenes .
 Insensitivity to growth-inhibitory (antigrowth) signals:
cancer cells inactivate tumour suppressor genes, that
normally inhibit growth.
 Evasion of programmed cell death (apoptosis): cancer cells
suppress and inactivate genes and pathways that normally
enable cells to die.
 Limitless replication potential: cancer cells activate specific
gene pathways that render them immortal even after
generations of growth.
 Tissue invasion and metastasis: cancer cells acquire the
capacity to migrate to other organs, invade other tissues, and
colonize these organs, resulting in their spread throughout the
body.

38. Types of Cancer
1. on the basis of their original tissue
from where they arose :
 Carcinoma is a cancer that starts in
the skin or the tissues that line other
organs.
 Sarcoma is a cancer of connective
tissues such as bones, muscles,
cartilage, and blood vessels.
 Leukaemia is a cancer of bone
marrow, which creates blood cells.
 Lymphoma and myeloma are
cancers of the immune system.

39. 2. On the basis of their
spread :
 Metastasis or Malignant tumour : Cancer can
spread from its original site by local spread,
lymphatic spread to regional lymph nodes or by
haematogenous spread via the blood to distant
sites, known as metastasis. When cancer spreads
by a haematogenous route, it usually spreads all
over the body.
 Benign tumours or Non-malignant tumour :
which do not spread to other parts of the body.
Possible signs and symptoms include a lump,
abnormal bleeding, prolonged cough, unexplained
weight loss and a change in bowel movements.

40. Causes of cancer:
 exposure to cancer-causing
chemicals, called carcinogens
 exposure to radiation
 unprotected exposure to the sun
 certain viruses, such as human
papilloma virus (HPV)
 smoking
 lifestyle choices, such as type of diet
and level of physical activity

41. Diagnosis of cancer
 Biopsy : In most cases, doctors need to do
a biopsy to make a diagnosis of cancer. A
biopsy is a procedure in which the doctor
removes a sample of tissue. A
pathologist then looks at the tissue under
a microscope to see if it is cancer.
 Tumour markers : Tumour markers are
used to detect, diagnose cancer by using
surface antigens, cytoplasmic proteins,
enzymes and hormones.

42.  Radiological Techniques: CT Scan,
MRI and X-rays may be employed to
detect cancer of internal organs like
kidney and pancreas.

43. The most common types of
treatment are:
 Surgery : Surgically removes as much of the cancer as possible.
 Chemotherapy : Uses medications that are toxic to cells to kill
rapidly-dividing cancer cells.
 Radiation Therapy : Uses powerful, focused beams of
radiation inside (brachytherapy) or outside (external beam
radiation) your body to kill cancer cells.
 Stem Cell (Bone Marrow) Transplant : Repairs diseased bone
marrow with healthy stem cells. Stem cells are undifferentiated
cells that can have a variety of functions. These transplants
allow doctors to use higher doses of chemotherapy to treat the
cancer.
 Immunotherapy (Biological Therapy) : Uses antibodies to
help your body’s immune system recognize cancer so it can fight
it off.
 Hormone Therapy : Removes or blocks hormones that fuel
certain cancers to stop cancer cells from growing.