Pathology

Definition:

The scientific study of disease is called pathology

Types of pathology:

A.     General pathology:

The study of basic or general principles of cells and tissues that under lie diseases is called general pathology

B.     Special pathology:

The study of diseases in the specific organ and tissue is called special pathology

Infection:

Any living entry which produces signs and symptoms is called infection

Infestation:

It is the state of having parasite in or on the body which includes arthropods or animal parasites.

Disease:

The absence of health is called disease. Any deviation from normal structure and function of any part which have signs and symptoms is termed as disease. Any change in normal state of the body is known as disease.

Core of pathology/ aspects of disease:

There are the following four aspects of diseases:

1)    Etiology (cause of disease):

There are two types of etiology.

        i.            Genetic:

It is due to abnormalities in chromosomes or mutations or defect in genes.

Example: thalasemia, hemophilia, sickle cell anemia etc

     ii.            Acquired:

This may be due to:

a.       Physical agents: accidents

b.      Chemical poisons: certain chemicals like organophosphorus poisoning

c.       Nutritional deficiencies: anemia, malnutrition etc

d.      Immunological: hypersensitivity or hyposensitivity reactions such as Asthma

e.      Infections: staphylococcus aureus is the common cause of boil

f.        Neoplasia: cancer

g.       Psychological factors: depression, anxiety etc

2)    Pathogenesis (mechanism of its development):

The sequence of events from the initial stimulus to the ultimate expression of the disease is called pathogenesis.

3)    Morphological changes (alteration in shape and size of the cells and organs):

The structural and functional changes in the cells due to disease are called morphological changes.

4)    Clinical significance (signs and symptoms):

It includes signs and symptoms, course and prognosis of the disease.

Biopsy:

The removal of tissue from the body during life diagnostic purposes is called biopsy.

Cytology:

The study of cells in the fluid medium is called cytology.

Histopathology:

The abnormal tissue or part of tissue which is examined under microscope is called histopathology.