Patholosis Lecture Notes - 1st Year Kasr Alainy Medical Students

General pathology flashcards covering definitions, cell injury, death, accumulations, calcifications, amyloidosis, and diagnostic techniques based on the lecture transcript.

Pathology

The scientific study of disease, including its functional and structural changes.

Epidemiology (Incidence)

The distribution and determinants of disease in different populations.

Etiology

The causes of disease, which can be primary (idiopathic), genetic, environmental, or multifactorial.

Pathogenesis

The mechanism by which the etiology produces the disease.

Morphology

The structural changes of a disease, studied either gross (surgical/autopsy) or microscopic (light/electron microscopy).

Lesion

A structural abnormality seen in an organ, such as a mass or an ulcer.

Complications (Sequelae)

The secondary effects of a disease, such as an intestinal obstruction caused by a tumor.

Prognosis (Outcome)

The course and fate of a disease, which can be changed by surgical or medical intervention.

Homeostasis

The normal balance between physiological demands and the limitations of cell structure and metabolic capacity.

Adaptation

A state where physiological or pathological stressors cause the cell to change while preserving its viability.

Hypertrophy

An adaptive response resulting in an increase in cell size, such as LVH in hypertension or aortic valve stenosis.

Hyperplasia

An adaptive response resulting in an increase in the number of cells.

Metaplasia

A change in cell type, such as squamous metaplasia or Barrett’s esophagus.

Hypoxia

Deprivation of $O_2$ supply which affects aerobic respiration, commonly caused by ischemia, decreased $O_2$ carrying capacity, or cardiorespiratory failure.

Ischemia

A cause of hypoxia resulting from arterial occlusion.

ROS (Reactive Oxygen Species)

Intracellular toxic oxygen free radicals containing single unpaired electrons at the outer orbit, including superoxide $O_2^-$, hydroxyl $OH^-$, and hydrogen peroxide $H_2O_2$.

Lipid Peroxidation

The oxidative stress-induced damage of lipids in the cell membrane.

Phospholipase

An enzyme activated by increased intracellular $Ca^{++}$ that degrades membrane phospholipids.

Protease

An enzyme that breaks down cellular proteins.

Endonuclease

An enzyme that causes DNA injury.

Karyolysis

The fading of nuclear basophilia (faint nuclear staining) during cell death.

Pyknosis

A stage of nuclear change where the nucleus shrinks and stains darkly (increased basophilia).

Karyorrhexis

Destructive nuclear fragmentation following pyknosis.

Necrosis

The death of a group of cells within a living body resulting in an inflammatory response and repair by fibrosis.

Coagulative Necrosis

A type of necrosis caused by a sudden cut in blood supply (acute ischemia) characterized by protein denaturation and preservation of cellular outlines (ghost cells).

Liquefactive Necrosis

A type of necrosis characterized by rapid liquefaction and lysis, common in nervous tissue or suppurative inflammation.

Caseous Necrosis

A type of necrosis with a semisolid yellowish-white 'cheesy' appearance, typically seen in tuberculosis lesions.

Fibrinoid Necrosis

A special form of necrosis in blood vessel walls featuring deposition of fibrin-like material, seen in immunological diseases like Polyarteritis Nodosa (PAN).

Apoptosis

Programmed, energy-dependent cell death involving the deletion of individual cells with intact membranes and no inflammatory response.

Caspase

An enzyme whose activation brings about apoptosis by destroying the nuclear membrane and activating DNAse.

Steatosis (Fatty Changes)

The abnormal accumulation of triglycerides (most common) within parenchymal cells like the liver (hepatocytes) or heart.

Xanthoma

Foamy clusters of macrophages overloaded with lipids, seen in hereditary or acquired hyperlipidemia.

Hyaline

A descriptive histological term for homogenous, glassy, pink-appearing protein material stained with H&E.

Mallory Bodies

Intracellular hyaline material found in hepatocytes due to chronic alcohol consumption.

Russell Bodies

Intracellular hyaline material (immunoglobulins) found in plasma cells during chronic inflammation.

Anthracosis

Exogenous pigmentation caused by the inhalation of carbon, appearing as black pigment in the lung and lymph nodes.

Lipofuscin

The 'wear-and-tear' pigment; an insoluble, brownish-yellow intracellular material resulting from lipid peroxidation of cell membranes.

Hemosiderin

A hemoglobin-derived, golden-yellow granular pigment containing ferritin micelles.

Hemochromatosis

The most common form of iron overload, often due to a congenital gene defect on chromosome 6, leading to tissue damage and organ dysfunction.

Hemozoin

A brown iron-containing pigment produced by blood-feeding parasites (Malaria, Bilharzia) that is not reactive to Prussian blue.

Dystrophic Calcification

Deposition of calcium in injured or necrotic dead tissue while serum calcium levels remain normal.

Metastatic Calcification

Deposition of calcium in normal living tissue due to hypercalcemia (high serum calcium levels).

Amyloidosis

Extracellular deposition of abnormal protein with a $\beta$-pleated configuration that appears waxy and hard.

Congo Red

A microscopic stain that colors amyloid orange-red and displays apple-green birefringence under polarized light.

Macroglossia

Enlargement of the tongue, which is the most common oral manifestation of systemic amyloidosis.

Surgical Pathology

The part of anatomic pathology that studies tissue and organ samples (biopsies) to obtain a diagnosis and determine prognosis.

Excisional Biopsy

A procedure where the whole lesion is removed for diagnosis.

Incisional Biopsy

A procedure where only a part of a lesion is sampled for diagnosis.

Cytology

A rapid, inexpensive method of patient evaluation that studies cell samples, such as smears (PAP smear) or fine needle aspirations (FNAC).