Human Health and disease 1

Question 1

good humor hypothesis

Answer 1

• Health, for a long time, was considered as a state of body and mind where
  there was a balance of certain ‘Humors’. (Asserted by Greek & Indian
  Ayurveda System Good Humor Hypothesis)
• It was thought that persons with ‘Black bile’ belonged to hot personality and
  would have fevers.
• Four humors  Black bile (spleen), yellow bile, phlegm (mucous) & blood.

Question 2

who disproved good humor hypothes

Answer 2

The discovery of blood
circulation by William Harvey using experimental method
and the demonstration of normal body temperature in
persons with blackbile using thermometer disproved the
‘good humor’ hypothesis of health.

Question 3

factors that affects health of a person

Answer 3

1. Genetic disorders- deficiencies with which a child is born and
   deficiencies/defects which the child inherits from parents from birth
2. Infections
3. Life style including food and water we take, rest and exercise we give to our
   bodies, habits that we have or lack e

Question 4

define health

Answer 4

• Health does not simply mean ‘absence of disease’ or ‘physical fitness’. It
  could be defined as a state of complete physical, mental and social well-
  being.
• When people are healthy, they are more efficient at work.
• This increases productivity and brings economic prosperity.
• Health also increases longevity of people and reduces infant and maternal
  mortality.
• Balanced diet, personal hygiene and regular exercise are very important
  to maintain good health.
• Yoga has been practiced since time immemorial to achieve physical and
  mental health.

Question 5

define diseases

Answer 5

When the functioning of one or more organs or systems of the body is
adversely affected, characterized by various signs and symptoms, we say that
we are not healthy, i.e., we have a Disease.

Infectious Disease
* Diseases which are easily
transmitted from one person to
another.
* Caused by Pathogen

Non Infectious Disease
* Diseases which are not transmitted
from one person to another.
* Caused due to hereditary factors,
lifestyle.

Question 6

typhoid fever
i) causative pathogen
ii) mode of infection
iii)symptoms and effects
iv) test for identification

Answer 6

i) It is caused by salmonella typhi( bacterium)

ii) These pathogens generally enter the small intestinethrough food and water contaminated with them and migrate to other
organs through blood.

iii)Sustained high fever (39° to 40°C), weakness,
stomach pain, constipation, headache and loss of appetite are some of
the common symptoms of this disease. Intestinal perforation and death
may occur in severe cases.

iv)Typhoid fever could be confirmed by Widal test : A classic case in medicine, that of Mary Mallon nicknamed Typhoid Mary, is worth mentioning here. She was a cook by profession
and was a typhoid carrier who continued to spread typhoid for several
years through the food she prepared.

Question 7

pneumonia
i) causative pathogen
ii) mode of infection
iii)symptoms and effects

Answer 7

i) Bacteria like Streptococcus pneumoniae and Haemophilus influenzae
are responsible for the disease pneumonia in humans which infects the
alveoli (air filled sacs) of the lungs.

ii) A healthy
person acquires the infection by inhaling the droplets/aerosols released
by an infected person or even by sharing glasses and utensils with an
infected person.

iii)As a result of the infection, the alveoli
get filled with fluid leading to severe problems in respiration. The symptoms
of pneumonia include fever, chills, cough and headache. In severe cases,
the lips and finger nails may turn gray to bluish in colour.

Question 8

common cold
i) causative pathogen
ii) mode of infection
iii)symptoms and effects

Answer 8

i)Rhino viruses
represent one such group of viruses which cause one of the most infectious
human ailments – the common cold.

ii)Droplets resulting from
cough or sneezes of an infected person are either inhaled directly or
transmitted through contaminated objects such as pens, books, cups,
doorknobs, computer keyboard or mouse, etc., and cause infection in a
healthy person.

iii)The common cold is characterised by nasal
congestion and discharge, sore throat, hoarseness, cough, headache,
tiredness, etc., which usually last for 3-7 days.

Question 9

causative organism of malaria

Answer 9

Plasmodium, a tiny protozoan is responsible for this disease. 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 one and can even be fatal.

Question 10

steps of infection of malaria

Answer 10

i) Plasmodium enters the human body as sporozoites (infectious form)
through the bite of infected female Anopheles mosquito.

ii) The parasites
initially multiply within the liver cells( They reproduce asexually in the liver cells, bursting the cells and releasing into blood) and then attack the red blood cells( parasites reproduce asexually in the rbc)
(RBCs) resulting in their rupture.

iii) The rupture of RBCs is associated with
release of a toxic substance, haemozoin, which is responsible for the chill
and high fever recurring every three to four days.

iv) The sexual stages of the parasite are formed in the RBC’s ( gametocytes)

v) When a female Anopheles
mosquito bites an infected person, these parasites( gamaetocytes) enter the mosquito’s
body and undergo further development. ( fertilization and development take place int he gut of the mosquito)

vi) The parasites multiply within
them to form sporozoites, which escape from the gut and migrate to salivary glands of mosquito where they are stored.

vii) When these mosquitoes bite a human, the sporozoites are introduced into his/
her body, thereby initiating the events mentioned above.

viii) It is interesting to note that the malarial parasite requires two hosts – human and mosquitoes – to complete its life cycle (Figure 7.1); the female Anopheles
mosquito is the vector (transmitting agent) too.

Question 11

ameobic dysentery
i) causative pathogen
ii) mode of infection
iii)symptoms and effects

Answer 11

i) Entameoba histolytica.Entamoeba histolytica is a protozoan parasite in the large intestine of
human which causes amoebiasis (amoebic dysentery).

ii)Houseflies act as mechanical carriers
and serve to transmit the parasite from faeces of infected person to food and food products, thereby contaminating them.
Drinking water and food contaminated by the faecal
matter are the main source of infection.

Question 12

filariasis
i) causative pathogen
ii) mode of infection
iii)symptoms and effects

Answer 12

Wuchereria (W. bancrofti and W. malayi), the filarial
worms cause a slowly developing chronic inflammation
of the organs in which they live for many years, usually
the lymphatic vessels of the lower limbs and the disease
is called elephantiasis or filariasis (Figure 7.2).

The
genital organs are also often affected, resulting in gross
deformities. The pathogens are transmitted to a healthy
person through the bite by the female mosquito vectors. ( Culex)

Question 13

ring worms
i) causative pathogen
ii) mode of infection
iii)symptoms and effects

Answer 13

i) Many fungi belonging to the genera Microsporum,
Trichophyton and Epidermophyton are
responsible for ringworms which is one of
the most common infectious diseases in man.

ii) Ringworms are generally
acquired from soil or by using towels, clothes
or even the comb of infected individuals.

iii)Appearance of dry, scaly lesions on various
parts of the body such as skin, nails and
scalp (Figure 7.3) are the main symptoms of
the disease. These lesions are accompanied
by intense itching. Heat and moisture help
these fungi to grow, which makes them thrive
in skin folds such as those in the groin or
between the toes.

Question 14

methods to prevent speread of diseases

Answer 14

• Maintenance of personal hygiene- consumption of clean drinking water,
  food, vegetables, fruits, etc.
• Maintenance of public hygiene- proper disposal of waste and excreta;
  periodic cleaning and disinfection of water reservoirs, pools, cesspools and
  tanks and observing standard practices of hygiene in public catering.
• In cases of air-borne diseases- contact with the infected persons or their
  belongings should be avoided.

For diseases such as malaria and filariasis- Control or eliminate the vectors
and their breeding places. Avoid stagnation of water in and around residential
areas, regular cleaning of household coolers, use of mosquito nets, introducing
fishes like Gambusia in ponds that feed on mosquito larvae, spraying of
insecticides in ditches, drainage areas and swamps, etc. Doors and windows
should be provided with wire mesh to prevent the entry of mosquitoes.

• Use of vaccines and immunization programmes have enabled us to
  completely eradicate a deadly disease like smallpox.
• Discovery of antibiotics and various other drugs has also
  enabled us to effectively treat infectious diseases.