Introduction of pathology

Pathology is derived from two Greek words pathos ( disease or suffering ) and logos ( study) .
Pathology means scientific study of structure and function of the body in disease .
Definition of pathology
it is abridging discipline involving both basic science and clinical practice and is devoted to the study of the structural and functional changes in cells, tissues, and organs that underlie disease

Pathology is divided in to two branches :-

A- General pathology :- deals with general changes in all tissues of the body e.g.. Inflammation, cancer, ageing, edema, hemorrhage ….etc .
B- Special or Systemic pathology :- study of diseases pertaining to specific organs and body systems e.g. Cardio Vascular System CVS, Central Nervous System CNS, Gastro Intestinal Tract GIT…..etc.

Specialties of pathology 1- Histopathology .2-Hematology3-Clinical pathology 4-Immunpathology 5-Experimental pathology6- Molecular pathology

What is the Disease?

It is the “State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal”
Disease may be defined as :
an abnormal alteration of structure or function in any part of the body.

There are four aspects of a disease process

1-cause (etiology),
2-pathogenesis (the mechanisms of its development ).
3-morphologic changes (the structural alterations induced in the cells and organs of the body ),
4- clinical significance(the functional consequences of the morphologic changes)



1- Etiology :- means study the causes of disease If the causes of disease is known its called primary etiology
If the causes of disease is un known its called idiopathic
There are two major classes of etiologic factors :-
A- Genetic or Intrinsic .
B-Acquired (infectious , nutritional , physical , and chemical).

• 2- Pathogenesis:- The sequence events in the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease,”from the time it is initiated to its final conclusion in recovery or death .

3- Morphological changes

Means all structural alterations in cell or tissue which occur following the pathogenic mechanisms .
These structural alterations can be seen with naked eye ( Gross morphological changes or macroscopic changes )
or under the microscope ( microscopic changes ).

Gross or macroscopic changes

size, shape
weight
color
consistency
surface
edge, section


:

4 - Clinical manifestations

Means the morphologic changes in the organ influence the normal function of the organ . these morphologic changes determine the clinical features ( signs and symptoms) ,course , and prognosis of disease

Signs In medical terms, the word ‘sign‘ is used by health care professionals to get actual information about the particular disease by asking symptoms from the patients and also using other measurable modes like the blood test, X-ray, observing temperature.The Signs are observable by feeling, hearing or on seeing and so is said to be the objective evidence of disease. For example swelling, fractures, bleeding are the signs. Hence signs are the physical demonstration of a disease, can be detected by doctors.

There are three types of medical signs:-

Anamnestic signs refer to the past experience of the disease or conditions. An example is paralysis stroke, heart attack.
Prognostic signs predict the future disease, means by observing the signs and symptoms doctor predicts the chances of occurrence of disease.
Diagnostic signs show the actual disease from which the person is suffering currently.

Symptoms

Symptoms are felt by the patient only; it is provided by the patient to the doctor, on the basis of which further diagnosis are done. Symptoms are said to be subjective as they can only be felt by the person. Example: shivering, headache, body ache, nausea, muscles fatigue. Symptoms can be considered as an indication of a particular disease; these are not visible to others. Symptoms should be taken seriously, and if noticed, one should consult a physician as soon as possible.

There are three types of medical symptoms

Chronic Symptoms: In this kind of symptom there is a long-lasting pain, which does not go away like in cancer, AIDS, asthma.
Relapsing symptoms: These are the symptoms which reoccur, after disappearing in the past. The best example is multiple sclerosis and cancer.
Remitting symptoms: Symptoms which get completely escape from the body.

prognosis

Expected outcome of the disease, It is the clinician's estimate of the severity and possible result of a disease.
Robbins Basic Pathology . Page 1