Mechanisms of Disease

Deficiency, Intoxication, and Trauma

3 essential means a cell can be injured from the perspective of the cells functional needs

Deficiency

Lack of substance necessary to the cell

Intoxication

Presence of a substance that interferes with cell function (Poisoning)

Trauma

Loss of the cell’s structural integrity-physical injury

Primary nutrient deficiency

A lack in the diet

Secondary nutrient deficiency

Substances are present in the diet but cannot be absorbed

Precursors

Starting forms

Improper regulation due to lack of controlling enzymes. Ex. Viral action

Disrupts cellular function

Viral action

Can cause systemic deficiencies. Following infection of a cell, the virus causes the cell to construct new virus particles, which are then released from the infected cell.

B. Intoxication

Substances interferes with normal functions when present within cells (Poison)

Toxins

Injurious substances, said to produce an intoxication

Exogenous

Toxins of external origin

Biological or nonbiological origin

Exogenous can be characterized as

Biological toxins

Produced by living organisms, most commonly microorganisms

Agents of infection

Gains access to body tissues and release injurious substances

Bacteria, fungi, protozoa

Most common source of biological toxins

Endogenous

Injurious substances that arises inside the cell

Chromosomal defects and Ionizing radiation

How endogenous toxins form

Chromosomal defects

Causes a toxic substance to be produced. (Ex. Result in the lack of an enzyme, some metabolic intermediate is normally consumed and the reaction sequence might build up to toxic levels.

Ionizing Radiation

Associated with x-rays and radioactivity

Physical injury, caused by physical agents

C. Trauma

Hypothermia

Extreme cold, injures cells as a result of ice crystal formation in the water of the cytoplasm (Frostbite)

Hyperthermia

Extreme heat, damages cells by disrupting and coagulating proteins. (Burns)

Mechanical Pressure

Increased pressure, cells are overwhelmed and can’t maintain structural integrity

Hypothermia, Hyperthermia, and Mechanical Pressure

3 types of Trauma

Structure and Function

Effects of cell injury depends on subtle interplay between

The nature of the causative agent, intensity, duration, and number of exposure

Effects of injury and the cell’s responses are determined by

Abrupt or insidious

Come chronic disease onset is

Insidious

Seemingly minor changes, don’t arouse immediate concern. (Progresses gradually with inapparent symptoms)

Local

Confined to one region of the body

Systemic

Affects a number of organs and tissues or affets the body as a whole

Prognosis

prediction of a particular disease’s outcome

Diagnosis

Identification of the patient’s specific disease

Therapy

Treatment with the aim of achieving a cure or reducing the signs and symptoms to a level where some functional capacity can be restored.