Pathology: General

By Aiman Zaher

Quick reference to Pathology, the basic cellular response to injuries, with succinct definitions ensuring this guide covers in 6 pages what you would usually find in 30 pages or more. This can be combined with the companion guides Pathology Systemic 1 and 2, putting these concise 6 page guides together for a solid 90 pages of information in 18 pages.

• Language: English
• Publisher: BarCharts, Inc.
• Release date: Nov 30, 2009
• ISBN: 9781423237860

Book preview

Cell Injury & Adaptation

Definitions

Pathology: The study of disease; pathology is divided into general pathology (the study of basic cellular responses to injuries) and systemic pathology (the study of specific organ responses to diseases)

Etiology: The underlying causes of a disease

Pathogenesis: The mechanism that leads to the signs and symptoms of a disease

Morphology: The gross or microscopic appearance of cells and tissues

Etiologies of Cell Injury

Hypoxia is an insufficient supply of oxygen to tissues, resulting in a decline of ATP synthesis and subsequent cell injury due to impairment of the Na-K-ATPase pump

Degree of hypoxic cell injury

Degree varies with each type of tissue

Brain tissue is the most susceptible; the kidney and heart are also sensitive

Causes of hypoxia

Ischemia: Insufficient arterial or venous flow (e.g., atherosclerosis, thrombosis)

Hypoxemia: Decreased oxygen concentration in the blood due to abnormal perfusion, ventilation, or diffusion

Hemoglobin problems: Changes in the structure or decline in the serum level of hemoglobin (e.g., anemia, methemoglobinemia in CO poisoning).

Free radical cell injury is caused by molecules with a single unpaired electron in an outer orbital (e.g., superoxide O2−, hydroxyl OH, drug and chemical free radicals, and ultraviolet (UV) light or radiation free radicals) that are able to combine to other molecules, resulting in the destruction and degradation of nucleic acids, proteins, and lipids; this process leads to the injury of cell membranes and organelles, along with possible cell death

Molecules that degrade free radicals or block their formation

Intracellular enzymes (e.g., glutathione peroxidase, catalase)

Antioxidants (e.g., ascorbic acid, vitamin E, vitamin A, vitamin C, carotenes)

Free radicals that cause injury

Chemical free radicals (e.g., carbon tetrachloride, iron, acetaminophen), which can lead to liver cell damage and necrosis

Free radicals that are generated after ischemia and reperfusion, as in myocardial infarction or cerebral vascular accident (e.g., O2 −, Ca2+)

Causes of Cell Injury

Insufficient adaptation to stress

May be physical, genetic, oxygenation based, chemical, nutritional, immunologic, or infectious

Adaptation to Cell Injury

Overview of cellular adaptation

Adaptation is the cell’s reaction to prolonged stress and repeated injury to protect itself and prevent recurrent injuries

Adaptations are either physical (morphologic) or functional

Etiologies of