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Pathophysiology – Exam 1 Study Notes
Health & Disease: Homeostasis
- Homeostasis—the maintenance of a relatively stable internal environment regardless of external changes Disease Process:
- Diagnosis - Identification of a basic disease
- Evaluation of signs and symptoms
- Laboratory tests
- Etiology - Causative factors in a particular disease
- Congenital defects, Inherited or genetic disorders, Microorganisms, Immunologic dysfunctions, Degenerative changes, Malignancy, Metabolic, nutritional problems, Trauma, burns, environmental factors Characteristics of Disease:
- Pathogenesis - Development of the disease
- Clinical Manifestations - Clinical evidence with signs and symptoms
- Local: at site of the problem
- Systemic: general indicators of illness, i.e. fever Disease Progression:
- Onset of disease
- Sudden/acute
- Insidious: gradual, vague or mild signs
- Acute disease
- Short-term, develops quickly. Less than 6 months in duration.
- High fever, severe pain etc.
- Chronic disease
- Develops gradually
- Milder symptoms, often intermittent with acute episodes (For instance Asthma is usually controlled but then there is a sudden asthma attack)
- Subclinical state
- Pathologic changes, no obvious manifestations
- Latent state
- No symptoms or clinical signs evident
- In infectious diseases: incubation period
- Prodromal period
- Early development of the disease
- Signs are nonspecific or absent
- Remissions and exacerbations
- Mark the course or progress of a disease
- Remission: period which manifestations subside
- Exacerbation: a worsening of severity
- Precipitating factor
- Condition that triggers an acute episode
- Complications
- New secondary or additional problems Cellular Adaptations:
- Atrophy - Decrease in the size of cells; Results in reduced tissue mass
- Dysplasia - Cells vary in size and shape within a tissue
- Hypertrophy - Increase in cell size; Results in enlarged tissue mass (working out)
- Hyperplasia – Increased number of cells, results in enlarged tissue mass.
- Metaplasia – Mature cell type is replaced by a different mature cell type
- Neoplasia – New growth – commonly called tumor Angiogenesis - the development of new capillaries (blood vessels. Cellular injury and Death: Causes: ischemia, chemicals, Physical (excessive heat or cold), radiation, mechanical damage (pressure or tearing of tissue), chemical toxins (exogenous- from environment, Endogenous – from inside the
- Essential to homeostasis
- Place for metabolic reactions
- Transportation system for the body
- Facilitating movements of body parts
- Fluid Compartments: Intracellular compartment – fluid inside the cells; major intracellular component is potassium Extracellular compartment – sodium outside of the body. includes intravascular fluid Interstitial fluid Cerebrospinal fluid Transcellular fluids Various secretions 60% of an adult’s body weight is water 70% of an infant’s body weight is water
- The amount of water entering the body should equal the amount of water leaving the body.
- Fluid intake: ingestion of solid food or fluids
- Fluid loss: urine, feces, perspiration, exhaled air
- Fluid circulates throughout the body via filtration and osmosis.
- Dependent on membrane permeability
- Water moves between compartments via:
- Hydrostatic pressure (blood Pressure)
- Osmotic pressure – Made up of plas
- Osmosis - Fluid constantly circulates throughout the body and moves relatively freely, depending on the permeability of the membranes between compartments
- Hydrostatic Pressure – (same as BP) pressure exerted by intravascular fluid (blood volume) or extravascular fluid on the wall of the blood vessel. (FORCE)
- Oncotic Pressure – made up of plasma proteins
Causes of Edema:
- Edema―excessive amount of fluid in the interstitial compartment
- Loss of Plasma Proteins
- Caused by high BP/increased Blood Volume
- Fluid forced out of the capillaries
- Obstruction of lymphatic circulation
- Increased capillary hydrostatic pressure
- Caused by higher blood pressure or increased blood volume
- Forces increased fluid out of capillaries into tissue
- Cause of pulmonary edema
- Loss of plasma proteins
- particularly albumin Results in decreased plasma osmotic pressure
- Obstruction of lymphatic circulation
- Causes localized edema
- Excessive fluid and protein not returned to general circulation
- Increased capillary permeability
- Usually causes localized edema.
- May result from an inflammatory response or infection.
- Histamines and other chemical mediators increase capillary permeability.
- Can also result from some bacterial toxins or large burn wounds and result in widespread edema. Fluid Excess:
- Tachypnea greater than 20 breaths per minute (respirations)
- Edema
- Low sodium
- S 1 S 2 S 3
- Crackles (abnormal lung sounds) Fluid Deficit: Dehydration:
- Insufficient body fluid – inadequate intake
Sodium Imbalance
- Primary cation in ECF
- Hyponatremia-too little sodium in the bloodstream
- Hypernatremia-too much sodium in the bloodstream
- Normal value in the blood = 135- 145 Hyponatremia (Sodium is less than 135 )
- Losses from excessive sweating, vomiting, diarrhea
- Use of certain diuretic drugs combined with low-salt diet
- Hormonal imbalances
- Insufficient aldosterone
- Adrenal insufficiency
- Excess ADH secretion
Effects:
- Diuresis
- Excessive water intake
- Low sodium levels
- Fatigue, muscle cramps, abdominal discomfort or cramps, nausea, vomiting
- Decreased osmotic pressure in ECF compartment
- Fluid shift into cells
- Hypovolemia and decreased blood pressure
- Cerebral edema Confusion, headache, weakness, seizures Hypernatremia (Sodium is more than 145)
- Cause is imbalance in sodium and water
- Insufficient ADH (diabetes insipidus)
- Results in large volume of dilute urine
- Loss of the thirst mechanism
- Watery diarrhea
- Prolonged periods of rapid respiration
- Ingestion of large amounts of sodium without enough water Effects:
- Weakness, agitation
- Dry, rough mucous membranes
- edema
- Increased thirst (if thirst mechanism is functional)
- Increased blood pressure Potassium Imbalance:
- Excreted primarily in urine
- Excess potassium ions in interstitial fluid may lead to hyperkalemia.
- Abnormal potassium levels cause changes in cardiac conduction and are life-threatening!
- Blood level normal value 3.5-5 mEq/L
- Compensation : deep rapid breathing , secretion of urine with low pH Respiratory alkalosis – hyperventilation Metabolic alkalosis – excessive ingestion of antacid Effects of alkalosis – increased irritability of the nervous system
- Restleness, muscle twitching, seizures, tertiary, coma
PAIN: Acute pain – sudden, sharp, localized pain related to thermal and physical stimuli primarily from skin and mucous membranes. It is transmitted by the A delta fibers. Chronic pain – diffuse, dull, burning or aching sensation and transmitted by c fibers. Long term. C fibers receive thermal, physical, and chemical stimuli from muscle, tendons, the myocardium, and the digestive tract as well as from the skin. Referred pain – occurs when an individual locates the pain at a site other than the actual origin. Phantom pain – pain or another sensation such as itching or tingling that occurs after amputation. Neuropathic Pain – caused by trauma or disease involving the peripheral nerves. Paresthesia, nerve pain, hands or feet are asleep. SKIN: First line of defense: non-specific, mechanical barrier, unbroken skin, mucous membranes. prevents excessive fluid loss, controls body temperature, synthesizes Vitamin D.
Second Line of Defense – non- specific, phagocytosis, inflammation, interferon Third line of defense – specific defense, cell mediated – t cells and cytokines. Humoral b cells and production of specific antibodies or cell mediated immunity. Layers of the Skin: Epidermis – avascular, dermis, SubQ (hypodermis) Cellulitis – infection of the dermis and SubQ tissues.
- Usually secondary to an injury
- Frequently in lower trunks and legs Signs and Symptoms : Area becomes red, swollen and painful
- Red streaks may develop, running along lymph vessels proximal to infected area Necrotizing Fasciitis – characterized by bacterial invasion with rapid tissue destruction and septic shock. (flesh eating disease) mixture of aerobic and anaerobic bacteria usually at site of infection.
- Severe inflammation and tissue necrosis
- Usually caused by virulent strain of gram positive, group A beta-hemolytic streptococcus
- History of minor trauma or infection in the skin.
- Very painful infected area rapidly increases in size, dermal gangrene is apparent. Impetigo – small red vesicles, rapidly enlarged, vesicles rupture. Yellowish-brown
Unit II
Acute inflammation- timing varies with specific cause Chemical mediates affect blood vessels and nerves in damaged area
- Vasodilation, hyperemia, increase capillary permeability
- Certain chronic diseases
- Presence of other disorders such as diabetes or cancer
- Irritation, bleeding, or excessive mobility
- Infection, foreign material, or exposure to radiation
- Chemotherapy treatment
- Prolonged use of glucocorticoids Healing by primary intention: The process involved when the wound is clean, free of foreign material and necrotic tissue and the edges are held close together creating a minimal gap between edges Healing by secondary intention: There is a large break in the tissue and consequently more inflammation, a longer healing period and formation of more scar tissue. Example: compound fracture. Basic concepts and processes – the major component of the body is water, essential to homeostasis, place for metabolic reactions, transportation system for the body, facilitating movements of body parts.
