Pathology Lab Topic: Introduction To Pathology - labsstudies

Pathology Lab Topic: Introduction To Pathology

Pathology Lab Topic: Introduction To Pathology

Definition of Pathology

  • The word pathology comes from the two Greek words “pathos”, which means suffering, and “logos”, which means study of.
  • It is the scientific study of body structure and function in disease.
  • It covers the cause, effects, course and nature of the disease.
  • It is an integrated discipline that combines basic science with clinical practice and is devoted to the study of structural and functional changes in cells, tissues and organs that cause disease.
  • It attempts to explain the causes and causes of a patient’s symptoms and signs while providing a sound basis for medical care and treatment.

Evolution of pathology

Pathological evolution begins with the following concepts in different eras.

  • Religious and superstitious beliefs from a logical point of view (Ancient to 1500 AD).
  • o The original concept of sickness was religious and superstitious belief  that pain or disease was the result of a curse or evil eye.
  • o The practical practice of medicine began between 460 and 377 BC (before Christ).
  • o Hippocrates introduced the concept of ethics in medical practice and loved/respected by the medical professions by Take the Hippocratic Oath when starting a medical practice .
  • The Era of  gross Pathology (1500-1800 AD).
  • o In this age, scientific discovery in scientific research involves the study of scientific fields of Human, autopsy, and microscopy in diagnosing diseased cellular tissues.
  • Era of Technological developments and the era of cytopathology (1800-1950 AD).
  •  In this era, the development of microscopy techniques was involve, includes different staining methods , using electron microscopy to examine and observe the high-level structure of cells and their organs.
  •  In this era, Papanicolaou introduced the psychology of exfoliation in the 1930s for the early detection of cervical cancer.
  • The Era of  modern Pathology  (1960s to early 2000s)
  •  Significant advances in molecular biology in the diagnosis and treatment of genetic diseases, immunity and cancer. These include:
  •  DNA structural information
  •  Chromosome identification and numbering
  •  Recombinant DNA methods
  •  Mammal formation

Divisions of Pathology

  • Human pathology is the largest branch of the disease
  • Usually divided into

o General Pathology

  •  Involves the general principles of disease, that is, the primary influence of cells and tissues on the abnormal stimuli that cause all diseases.

o System Pathology

  •  It includes the diagnosis of diseases related to specific organs and systems of the body.
  • This will examine the specific responses of specific organs and tissues to more or less defined stimuli.
  • Using histopathology similar with anatomical pathology or pathology anatomy is the most common research method and remains the most useful method that has stood the test of time.

Histopathology involves three (3) subdivisions.

  •  A type of surgical pathology used to examine tissue removed from living organisms.
  •  Examination of  biopsy and autopsy includes examination of organs and tissues removed from the cadaver.
  • Cytopathology includes examination of cells hidden in the lesion. Example fine needle aspirate specimen used in cytology.


Disease Development


  • This is a loss of physical convenience
  • Contrary to health, unhealthy is disease
  • The four components of the disease process that underlie the Pathology are:
  •  Its cause or etiology
  •  The Mechanism of its development , pathogenesis
  •  Structural changes, morphological changes caused by cells and organs of the body
  •  Practical consequences of morphological changes, health implications

Aetiology or Cause

  • Knowledge or discovery of the underlying cause remains the spinal cord from which a diagnosis, definitive diagnosis, or treatment can be established.
  • There are two main categories of Aetiologic factors:
  •  Origin or genetics
  •  Environments 
  • Genetic factors are clearly involved in some diseases caused by the environment, such as cancer and atherosclerosis
  • The environment can also have a profound effect on some genetic diseases

Environmental Factors

  • They are numerous and categorized as follows:
  •  Physical factors, which include trauma, radiation, extreme heat and cold, electricity, ie any form of excessive energy expenditure of the body.
  •  Chemical toxins, which have increased with advances in industrial processing, some act in a general way, i.e. toxic effects on all cells. Some act as acids and dermal agents on the skin and mucous membranes, and some affect certain organs such as the lungs, kidneys, liver and pancreas.
  • Malnutrition  which result from insufficient supply, disturbance and absorption, improper transport in the body.
  • The Effects may be of a general nature, such as starvation or hypoxia.
  • The Special damage may occur, eg in vitamin deficiencies.
  •  Overnutrition can lead to many systemic diseases, such as heart disease.
  •  Infections, viruses, bacteria, fungi, protozoa and metazoans all cause disease.
  •  They may do this by causing direct damage to the tissue, or the damage may be due to toxins produced by these bacteria.
  •  Abnormal immune response, the immune process is often immunosuppressive but may not be fully understood.
  •  Increased sensitivity to various substances can lead to serious conditions, such as allergic reactions.
  •  The immune system can act on the body’s cells—the body’s immune system.
  • Psychological factors contribute to and influence the disease process in a number of ways.
  •  Psychological stress can lead to mental illness.
  •  Their impact on individual symptoms and response to established medical conditions is evident.
  •  They are an important part of addiction-related disorders, such as alcohol and tobacco.
  •  Psychological factors are related to diseases such as hypertension, gastric ulcer, cardiovascular thrombosis, and peptic ulcer.

Genetic Factors

  • It is primarily the result of individual gene and genome activity. Normal and abnormal genes affect disease remission and resistance.
  • Normal gene
  • Affected by fair (light ) damaged skin such as skin cancer and UV radiation from the sun. This is due to the lack of a protective pigment called melanin.
  •  Blood type A is associated with an increased incidence of dangerous anemia and gastric cancer. Blood type B is associated with duodenal ulcers.
  •  Human leukocyte antigen (HLA) is associated with susceptibility and resistance to infection and the development of immune diseases.


  • Abnormal genes
  •  Mutations cause variations in chromosomal and genetic components; many occur spontaneously for no reason, and in some cases, become electrically charged by radiation, chemicals, or infectious agents.
  •  With hereditary diseases, genetic defects directly determine the disease, but most diseases are multifaceted genetic and environmental factors.
  •  A specific genetic defect has been found in stem cells that contributes to the growth of malignant tumors.


  • Refers to the sequence of events in the response of a cell or tissue to a pathogen, from the initial stimulus to the final manifestation of the disease.
  • Pathogenesis studies are still in the main field of pathology Morphological changes
  • Refers to structural changes in cells or tissues that are characteristic of a disease or process causative diagnosis.

Functional deficits and clinical significance

  • The nature of morphological changes and their distribution in different organs or tissues affects normal function and determines the clinical features, course and prognosis of the disease.
  • All types of joint damage begin with molecular or structural changes in cells.
  • Cell-matrix-matrix interactions significantly promote wound healing, leading to joint tissue and organ damage, which is as important as cellular damage in determining disease patterns and morphology.
  • The inability to cope with what is seen in the pathology can be caused by:
  • Inability to respond correctly, a serious infection in which the body does not respond.
  •  The disease is in part the result of systemic changes in the host, not in its favor.

 For example, antibodies that help destroy harmful parasites (such as bacteria) may cause disease due to mutations in host tissues, but they may be mistakenly considered foreign and cause damaging immune responses, such as various allergic reactions.

Disease classification

  • This disease is usually caused by the deterioration of living systems.
  • Once the pathological process begins with one major event leading to another, adaptation failures may stabilize and continue.
  •  This is most common in chronic (chronic) diseases and is usually caused by inappropriate activation of the homeostatic system.
  • When the body responds rapidly to adverse environmental events, the response is often excessive.

 Under normal circumstances, if more leukocytes are needed, the bone marrow will supply the appropriate amount in case there is a significant additional pathological release from the bone marrow.

  • Pathological wars, such as those between bacteria and humans, tend to fight in unity rather than outright victory. The reason for this paradox is the conclusion that natural selection favors both the parasite and the host.
  • Reflection on the above topics provides a starting point for the basic concept of disease.
  • The basis of the immune response can be divided into:
  •  Congenital
  •  Inflammation
  •  Damaged
  •  Tumor
  • The disease usually develops after cells or tissues have been injured or damaged by various factors and fail to mutate.


• Kumar, A. et al (2004). Robbins Basic Pathology. WB: Saunders.
• Spector, T.D. & Axford, J. S. (1999). Introduction to General Pathology. Edinburgh: Churchill Livingstone.
• Walter, J.B, & Talbot, I. C. (1996). General Pathology. New York: Churchill Livingstone.

You may also like...

Leave a Reply

Your email address will not be published.