This document provides an overview of basic pathology concepts. It discusses that pathology is the study of diseases and involves investigating the causes, mechanisms, and structural and functional changes that occur in cells and tissues. Pathology is divided into general pathology, which examines cellular reactions to stimuli, and systemic pathology, which examines organ-specific disorders. The document also defines key terminology like etiology, pathogenesis, and clinical manifestations. It describes different disease types and explains cellular adaptation processes like atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia that can occur in response to stressors or damage.

1. Basic Pathology
Introduction, Cell & Tissue Damage
Francis G. Kazoba BSc.RTT

2. Pathology
• Pathology is the study of suffering/diseases.
• It is derived from two Greek words pathos (disease) and logos
(study).
• It is devoted to the study of the structural, biochemical, and
functional changes in cells, tissues, and organs that underlie disease.
• Involves basic medical sciences and clinical practice to investigates of
the causes (etiology) of the diseases and the mechanism of disease
development (pathogenesis)

3. Branches of Pathology
• The study of pathology is divided into general pathology and
systemic pathology.
• General pathology is concerned with the reactions of cells and tissues
to abnormal stimuli and to inherited defects, which are the main
causes of disease.
• Systemic pathology examines the alterations in specialized organs
and tissues that are responsible for disorders that involve these
organs.

4. Basic Terminology
Disease
Etiology
Pathogenesis
Diagnosis
Clinical manifestation - Signs and symptoms
Prognosis
Epidemiology

5. Disease
• Disease is a condition in which the presence of an abnormality of
the body causes a loss of normal health
Idiopathic – no identifiable causes
Iatrogenic – occur as a result from medical treatment
Congenital – disease existing at birth or before birth, involves in the
development of fetus
Acquired - develops post – fetally
Nosocomial – due to being in a hospital environments

6. Aspects of Disease
• The four aspects of a disease process that form the core of
• pathology are its cause (etiology), the mechanisms of its development
• (pathogenesis), the biochemical and structural alterations
• induced in the cells and organs of the body (molecular
• and morphologic changes), and the functional consequences of
• these changes (clinical manifestations).

7. Etiology
• Refers to the study of the cause of the disease.
• During early time if someone became ill it was the patient’s own fault
(for having sinned) or the effects of outside agents, such as bad
smells, cold, evil spirits, or gods.
• We now recognize that there are two major classes of etiologic
factors: genetic (e.g., inherited mutations and disease-associated
gene variants, or polymorphisms) and acquired (chemical, physical,
infective agents , radiation, mechanical trauma, malnutrition).

8. Pathogenesis
• Is the mechanism of disease development in the body.
• Is a mechanism of the disease which etiology operates to produce the
pathological and clinical manifestation.
• Pathogenesis refers to the sequence of events in the response of cells
or tissues to the etiologic agent from the initial stimulus to the
ultimate expression of the disease.
• Pathogenesis can be shown by inflammation, degeneration, immune
response.

9. Pathogenesis of malaria

10. Diagnosis
• Refers to the process of attempting to determine or identify a
possible disease or disorder.
• The method of disease diagnosis involves
Physical examination.
Laboratory tests.
Imaging tests.
Biopsy.
• Prognosis refers to the expected outcome of a disease.

11. Clinical manifestation
• Are the signs and symptoms or evidence of disease.
• Signs – objective alteration that can be observe or measured by
another person; pulse rate, blood pressure, Temperature etc.
• Symptoms – subjective experiences reported by the person,
complains such as pain, nausea, vomiting etc.

12. Epidemiology
• Is the study of tracking patterns of disease occurrence and
distribution among populations and by geographic areas.
• Incidence of a disease– is the number of new cases occurring in
specific time of period
• Prevalence of a disease – is the number of existing cases within a
populations during the specific time of period.

13. Naming of diseases
Root- the foundation of the word
Prefix – place before the root to modify its meaning
Suffix – places after root to modify and give essential meaning to the
root
1. Hyperlipoproteinemia
• Prefix : hyper (higher)
• Roots : lipoprotein
• Suffix : -emia (blood condition)

14. Naming of diseases
2. Hepatomegaly
• Root : hepato (liver)
• Suffix : -megaly (enlargement)
3. Meningitis
• Root : mening (meninges)
• Suffix : - itis (inflammation)
4. Tachycardia
• Root : cardia (heart)
• Prefix : tachy – (fast/rapid)

15. Cell injury
• The normal cell is confined to a fairly narrow range of function and
structure by its state of metabolism, differentiation, and specialization
called homeostasis.
• Adaptations are reversible functional and structural responses to more
severe physiologic stresses and some pathologic stimuli, during which new
but altered steady states are achieved, allowing the cell to survive and
continue to function.
• The adaptive response may consist of
an increase in the size of cells (hypertrophy)and functional activity,
an increase in their number (hyperplasia),
a decrease in the size and metabolic activity of cells(atrophy),
or a change in the phenotype of cells (metaplasia).

16. Cell injury
• Cell injury is reversible up to a certain point, but if the stimulus
persists or is severe enough from the beginning, the cell suffers
irreversible injury and ultimately cell death.
• Adaptation, reversible injury, and cell death may be stages of
progressive impairment following different types of insults.

17. Summary
• All forms of disease start with molecular or structural alterations in
cells.
• Consideration of pathology starts with the study of the causes,
mechanisms, and morphologic and biochemical correlates of cell
injury.
• Injury to cells and to extracellular matrix ultimately leads to tissue and
organ injury, which determine the morphologic and clinical patterns
of disease.

19. Cellular adaptation
• Under normal conditions, cells must constantly adapt to changes is
their environment (physiological, pathological).
• The common cellular adaptation process includes
Atrophy
Hypertrophy
Hyperplasia
Dysplasia
Metaplasia

20. Atrophy
• Shrinkage of the size of the cells by the lost of the cells substance.
• The entire tissue or organs diminishes in size and function.
• Atrophy may be due to
Decrease in workload,
Lost of nerve innervations,
Lack of blood supply,
Inadequate nutrition,
Lost of endocrine stimulation and
Aging process

21. Atrophy

22. Hypertrophy
• Increase the size of the cells and consequently the size of the organs
• Hypertrophy is due to increase of the synthesis of structural protein
and organelles.
• Can be physiologic (ex;increase workload during exercise, uterine
myometrium during pregnancy) and pathologic (hypertrophy of
myocardium – hypertension/aortic valve disease)

23. Hypertrophy

24. Hyperplasia
• Increase the number of cells in an organ or tissue. (increase rate of
cellular division).
• Hyperplasia can be
Physiological hyperplasia
oIncrease in the size of breast during lactation and puberty , increase in
thickness of endometrium during menstrual cycle and liver growth
and regeneration after partial hepatectomy.

25. Hyperplasia
 Pathological hyperplasia
o Endometrial hyperplasia due to excess of estrogen hormones
o Benign prostatic hyperplasia due to excess androgens
o Skin warts due to viral infection

26. Hyperplasia

27. Metaplasia
• Is a replacement of one differentiated somatic cell type with another
differentiated somatic cell type of the same tissue.
• Adaptation of cells that are sensitive to particular stress to cell types
better able to withstand the adverse of environment.

28. Metaplasia

29. Dysplasia
• Not a true cellular adaptation as it is the form of hyperplasia.
• Abnormal change in the size, shape and organization of mature cells.
• Strongly associated with common neoplastic growth Example: CIN –
cervical intraepithelial neoplasia.

30. Pathoslogos