Pathology I Definitions and Concepts Week I

What are the five primary causes of extrinsic cell injury?

Thermal injury, trauma, toxins, radiation, infectious agents

what are the six primary causes of intrinsic cell death?

Nutritional, immune-mediated, neoplasia, genetic mutation, aging, endocrine

What are the three primary mechanisms of cell injury?

ATP depletion, oxygen-derived free radical damage, membrane damage

What causes ATP depletion?

Hypoxia and toxic injury

Describe hydropic degeneration

Sodium-potassium pumps require ATP in order to function. If there is a deficiency in ATP, sodium will be unable to exit the cell as efficiently, leading to the cell swelling with water and ultimately cells death.

What are the three primary results from ATP depletion leading to cell death?

Hydropic degeneration, accumulation of calcium and increased anaerobic glycolysis

What is ischemia?

Decrease of blood flow

What are reactive oxygen species?

Type of free radical that is produced during mitochondrial respiration that is normally degraded and removed by free radical scavengers

What substances prevent the initiation of the promotion of ROS to prevent the chances of oxidative stress from occurring?

Antioxidants

Pyknosis

Aspect of cell necrosis where nucleus shrinks

Karyorrhexis

Aspect of necrosis in which the nucleus becomes fragmented

Karyolysis

Aspect of necrosis where the chromatin in the nucleolus is actively dissolving

What are the two main patterns of tissue necrosis? What is the difference between them?

Coagulative and liquefactive necrosis. Architecture is preserved during coagulative necrosis.

Where does coagulative necrosis occur?

In areas of decreased blood flow

What is an infarct?

An area of necrosis due to decreased blood flow

What are two different gross patterns of tissue necrosis?

Caseous necrosis and gangrenous necrosis

What is caseous necrosis?

Caseous necrosis is when necrotic tissue turns into a friable mass, somewhat looking like cheese

What is gangrenous necrosis?

ischemic necrosis during a bacterial infection

What is hypertrophy?

An increase in cell size, especially in tissues that cannot readily divide

What is hyperplasia?

Increase in cell number, increased mass of tissue, can be physiologic or pathologic

What is atrophy?

A decrease in the size of cell, tissue or organ after mature size is reached

What are some causes of atrophy?

Deficient nutrient supply, decreased workload, pressure, endocrine imbalances

What is hypoplasia?

A congenital decrease in size due to failure of development

Metaplasia

One adult cell type is replaced by another adult cell type

What is dysplasia?

Disorderly growth of cells (usually epithelial cells), can be a prelude to neoplasia

Edema

Accumulation of fluid in the interstitial tissue spaces of the body or body cavities

What are the three mechanisms that lead to edema occurring?

increase in hydrostatic pressure, decrease in osmotic pressure, increase in vascular permeability

Hydropericardium

Fluid in the heart

Hydrothorax

Fluid in the thorax

Ascites

Fluid in the abdomen

Anasarca

Generalized fluid throughout the body

What is hyperemia?

Active engorgement of the vascular bed with blood (an increased inflow)

What is congestion?

Passive engorgement of the vascular bed with blood (decreased inflow), often accompanied by edema and hemorrhage

What are some causes of congestion?

Cardiac failure (right-sided vs left-sided), obstruction of venous outflow, vasodilation

What is hemorrhage?

loss of blood from vascular components

What are main causes of hemorrhage?

Physical vessel damage, movement of erythrocytes across intact vessel walls, decrease in platelet numbers (thrombocytopenia), decrease in platelet function (aspirin), decrease in coagulation factors