Conditions of Disease or Injury A. Hypoxia: decreased concentration of oxygen in the tissues Causes : - inadequate O2 intake (RS) - inadequate O2 delivery (CVS) - lack of Hgb. The cell needs O2 to be used by the mitochondria for ATP production. Without oxygen, this process cannot occur.

Consequences of Hypoxia : Inadequate/ lack of ATP No cellular functions, including the Na-K pump sodium diffuses into the cell drawing water cell begins to swell and burst Hypoxia production of lactic acid, (which occurs during anaerobic glycolysis) ph damage to the nuclear structures. If oxygen is returned within a certain period of time, the consequences are reversible.

Clinical Manifestations of hypoxia: If the source of hypoxia is RF or MI, all tissues will be affected. Cell death may occur. Tachycardia. Tachypnea. Muscle weakness. Alteration of consciousness Complications of hypoxia: - Altered consciousness coma death. -Organ failure(respiratory, cardiac, renal failure). Treatment Increase oxygen in inspired air (mask / mechanical ventilation).

B. Temperature Extremes: - Exposure to very high temperatures (burn, directly kill cells / indirectly by causing coagulation of blood vessels or the breakdown of cell membranes) . - Exposure to very cold temperatures 1.constriction of BV delivering nutrients and O2 to the extremities 2. formation of ice crystals in the cells. leading to cell lysis (bursting). Prolonged exposure to cold can lead to hypothermia.

Clinical Manifestations of Cold Exposure and Hypothermia - Numbness or tingling of the skin or extremities. - Pale or cyanosed skin (cold). - Shivering early on, then lack of shivering as condition worsens. - Decreased level of consciousness , drowsiness, and confusion. Complications - Blood clotting, characterized by pain and a decrease in pulse downstream from the clot. If blood flow is inadequate, gangrene may result. - Frostbite. - Ventricular dysrhythmia.

C. Radiation Injury High-energy radiation (UV radiation) is called ionizing radiation because it can displace electrons off atoms or molecules. Ionizing radiation is emitted by the sun, in x-rays, and in nuclear weapons. - Low-energy radiation is called non-ionizing radiation Effects of Ionizing Radiation : - May injure or kill cells directly by destroying the cell membrane and cell lysis Inflammation (S&Sx) - May also lead to mistakes in DNA replication which may cause programmed cell death or subsequent cancer .

Cells Susceptible to Ionizing Radiation : Cells that undergo frequent divisions, (gastrointestinal tract (GIT), the integument (skin and hair), and the blood-forming cells of the bone marrow. Fetus Effects of Non-Ionizing Radiation Non-ionizing radiation (microwave & US). The energy of this radiation is too low to break DNA bonds or damage the cell membrane.

Clinical Manifestations of Ionizing Radiation - Skin redness or breakdown. - With high doses, vomiting and nausea caused by GI damage. - Anemia (bone marrow ). - Cancer may develop years after the exposure . Treatment - Damage caused by low doses will be repaired and does not require treatment. - Cancers should be treated .

Pediatric Consideration - Fetal cells, highly susceptible to the damaging effects of ionizing radiation. - Infants and young children also experience periods of rapid cellular growth and are at risk of genetic damage from ionizing radiation. Studies suggest that there are no apparent health risks to fetuses exposed to non-ionizing radiation .

D. Injury Caused by MO Microorganisms infectious to humans include bacteria, viruses, mycoplasmas, rickettsiae, chlamydiae, fungi, and protozoa. Mo may be introduced directly or indirectly Cells of the body may be destroyed -directly by the microorganism or by a toxin released from the microorganism, - or indirectly injured as a result of the immune and inflammatory reactions .

Clinical Manifestations Infection by bacteria and viruses, often results in: - Regional lymph node enlargement - Fever (usually low-grade with a viral infection) - Body aches - Skin rash or eruption, especially with viral infections - Site-specific responses, such as pharyngitis, cough, otitis media---etc. Treatment - Bacteria and mycoplasmas are treated with antibiotics, preferably after culturing the infection . - Certain viral infections may be treated with antiviral agents. Other viral infections usually are left to resolve on their own.