Lecture #1 - FIRST PART

Pathology

Pathology

The study of the structural, functional, biochemical changes in cells, tissues and organs that underlie a disease

Anatomical Pathology

Type of pathology that involves the examination of surgical specimens removed from the body or sometimes the examination of the whole body to investigate and diagnose disease.

Surgical Pathology

Type of pathology that involves the examination of a specimen that is removed or obtained from the body to see if it is cancerous or not.

Histopathology

Type of pathology that involves examination of cells and tissues under the microscope, and utilizes H+E staining.

Cytopathology

Type of pathology that involves examination of cells shed into body fluids or obtained through scrapping or aspiration, such as sputum washings

Clinical Pathology

Type of pathology that involves laboratory analysis of body fluids and bodily tissues for disease diagnosis.

Molecular Pathology

Focuses on the disease at the sub microscopic level

Labile cells

• Cells that continue to proliferate throughout life

• They frequently undergo cell division to replace lost cells

• Cells that are from the surface of ET cells

Stable cells

• Definite pattern of replication with cells lost by wear and tear being replaced by the mitotic activity of others.

• Cell division does not occur frequently

• Division only occurs when there are injured cells

Example includes parenchymal cells of liver and kidney

Permanent cells

• These are non-replicating cells

• They are not capable of cell division

Example includes neurons / nerve cells

Aplasia

• Incomplete or defective development of tissue or organs.

• Affected tissue does not show resemblance to normal adult structure

Example includes paired organs like kidneys and gonads

Agenesia

The complete non-appearance of tissue or organ

Hypoplasia

It refers to the failure of tissue/organ to reach its normal mature adult size

Atresia

• Failure of tissue/organ to form an opening

Example includes an imperferate anus, Microtia, and Biliary atresia

Microtia

Absence of ear canal

Atrophy

• Acquired decrease in tissue or organ size

Example includes formation of intracytoplasmic vacuoles, also called AUTOPHAGIC

Physiologic atrophy

Happens as consequence of maturation

Pathologic atrophy

Decrease in size is due to a disease

Vascular atrophy

Type of atrophy due to lack of blood supply or diminished blood supply

Pressure atrophy

Type of atrophy due to persistent pressure applied to organ

Starvation atrophy

Type of atrophy due to lack of nutritional supply needed for normal growth

Atrophy of disuse

Type of atrophy due to diminished activity or inactivity

Exhaustion atrophy

Type of atrophy due to excessive workload

Endocrine atrophy

Type of atrophy due to lack of hormones needed to maintain normal size

Hypertrophy

• The increase in tissue/organ size due to an increase in the size of individual cells making up that organ

• No new cells are produced

• Seen in skeletal and cardiac muscles

Physiologic hypertrophy

Type of hypertrophy that causes an increase in muscle due to exercise

Compensatory hypertrophy

Type of hypertrophy that happens when one of the paired organs is removed

Pathologic hypertrophy

Type of hypertrophy of the Myocardium due to hypertension

Hyperplasia

It is the increase in tissue/organ size due to an increase in the number of cells.

Neoplasia

• Process of tumor formation

• Characterized as continuous proliferation of abnormal cells.

• Cells that are useless

Grave’s Disease

Diffuse crowding of epithelial cells forming papillary projections

Metaplasia

• Transformation of adult cell into another adult cell

• It is a reversible process

Dysplasia

• a.k.a Atypical metaplasia

• Change in size, shape, and orientation

• It is a reversible once stimulus is removed

Anaplasia

• a.k.a De-differentiation

• It is an irreversible process

• Transformation of adult cell intro embryonic cells

• It is used as a criterion for malignancy

Cellular Injury

This happens when limits of adaptive response is exceeded and when cells are exposed to injurious agent or stressful stimuli

Causes of Cellular Injury

• Anoxia, Ischemia, Anemia, CO2 poisoning, decreased perfusion of tissues by oxygen carrying blood, poor oxygenation of blood

• Physical agents

• Chemical agents

• Infectious agents

• Immunologic reactions

• Genetic defects

• Nutritional imbalances

Cellular swelling and Eosinophilia

These are microscopic changes in Reversible Injury

Carbon, silica, iron

These are exogenous pigments that accumulates in Reversible Injury

Melanin, bilirubin, hemosiderin, lipofuscin

These are endogenous pigments that accumulates in Reversible Injury

• Nuclear aggregations

• Dilation of ER

• Mitochondrial changes

• Plasma membrane alterations

These are ultrastructural changes in Reversible Injury