What is Pathology? this Introduction to Pathology Disease

Posted by hidup sehat On Thursday, November 3, 2011 0 comments
The scientific study of disease is called pathology. It is the study of how the organs and tissues of a healthy body change to those of a sick person.
Pathology is classified in several ways; it may be divided in:

  • General and Special pathology OR
  • Clinical and anatomical pathology
General pathology
It is the study of the basic reactions of cells and tissues to abnormal stimuli that under lie all diseases i.e. it describes basic principles and mechanisms of disease production. For example: such basic principle may be inflammation.
Special pathology
It is the study of specific responses of specialized organs and tissues to more or less well-defined stimuli i.e. special pathology deals with disease of specific organs or systems of the body. For example: inflammation in lung or kidney.
Any deviation from or interruption of the normal structure or function of any part. Organ or system of the body that is manifested by a characteristic set of signs and symptoms is called disease.

Classification of Disease
  • Inflammatory disease i.e tuberculosis appendicitis.
  • Degenerative disease e.g osteoarthritis etc.
  • Neoplastic disease e.g. lung cancer, breast cancer etc
  • Traumatic diseases e.g fracture of bone.
Core of pathology comprises the four aspects of a disease that are:
  • Etiology (cause of disease)
  • Pathogenesis (mechanism of its developments)
  • Morphologic changes (structural alterations included in the cells and organs of the body)
  • Clinical significance (functional consequences of the morphologic changes)
There are two groups of etiology.
  • Genetical
  • Acquired

Genetical : Due to abnormalities of chromosomes called mutations or defect in genes.
Acquired : Which may be caused by:
  • Physical agents
  • Chemical poisons
  • Nutritional deficiencies
  • Infections
  • Abnormal Immunological reactions
  • Psychological factors
Pathogenesis means the sequence of events the cells or tissues or the whole organism in response to the causative agent – from the initial stimulus to the ultimate expression of the manifestation of the disease.
Morphologic Changes:
This refers to the structural and associated functional changes in the cells or tissues that are either characteristic of the disease or diagnostic of the etiologic process.
Clinical Significance
It refers to the signs and symptoms. Course and prognosis of the disease.
The removal of tissue from body during life for diagnostic purposes is called biopsy.
The study of individual cell is called cytology.
  • Simple columnar: GIT (Stomach recturn), gall bladder, and cervix.
  • Ciliated pseudostratfied columnar: Respiratory tract. (Trachea, Bronchi. Larynx, nasopharynx)
  • Stratified squamous: Skin epidermis, oral, lip, tongue, pharynx, esophagus.
  • Transitional stratified: Urinary bladder, pelvis.

The cell has three parts i.e cell membrane, nucleus and cytoplasm. In cytoplasm there are some organelles serving various functions.
  1. Mitochondria: It is power house of the cell, extracts energy from nutrients in the form of ATP.
  2. Ribosomes: They synthesize protein in the cell.
  3. Lysosomes: They provide an intracellular digestive system that allows the cell to digest and remove unwanted substances such as bacteria.
  4. Endoplasmic Reticulum: It detoxifies the damaging substances to the cell.
  5. Cell Membrane: It maintains fluid ionic balance and provides pathway for controlled transport of various substances.
  6. Nucleus: It is the control centre of the cell and is composed of DNA.

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