Misc Flashcards
TB
Tuberculosis (TB) is a major chronic, progressive communicable disease caused by Mycobacterium tuberculosis. It occurs most commonly in the lungs and usually features a period of latency, sometimes for many years, following initial infection. Extrapulmonary sites (e.g., vertebrae, meninges) may also be infected. TB incites distinctive chronic granulomatous inflammation, which features a central area of semi-solid crumbly, necrotic tissue called caseous necrosis (Latin caseus = cheesy).
Clinical and chest X-ray findings may add up to a very high index of suspicion, but positive diagnosis rests on detection of acid-fast organisms in sputum cultures or smears or by other direct laboratory detection. The purified protein derivative (PPD) test (also known as the Mantoux test) is a skin test for infection. As it is positive in both latent and active cases, it is not diagnostic of active disease. The test is performed by injecting treated TB protein (tuberculin) into the patient’s skin (see The Clinical Side, “The Mantoux Skin Test”).
Red marrow
actively produces blood cells
Yellow marrow
storehouse for fat, although it can become red marrow if necessary
70% of the cross-sectional area of the vessel must be occluded before causing clinical symptoms as a result of impaired flow
Talking atheromas!!!!
Etiology:
cause of disease
pathogenesis
natural history and development of disease process
pathophysiology
the manner in which the incorrect function is expressed
idiopathic
etiology is unknown
Iatrogenic
if disease is byproduct of medical treatment/diagnosis
nosocomial
if disease originates while hospitalized
cell injur
commonly occurs due to inadequate oxygenation. Without O2, cells can’t create energy and die. Anoxia total lack of O2, hypoxia partial. Ischemia causes hypoxia and nutrient delivery
physical, thermal, chemical agents
disrupt the structure of organs or tissues.
Physical: force can cause fatal hemorrhage and ischemia
Thermal: frostbite
Chemical: acids, alkalis, or heat causing death to skin etc
ionizing radiation
enough to break (ionize) water (H2O) into H+ (hydrogen ion) and OH- (hydroxyl ion)
Acute radiation therapy: OH- attaches to DNA and prevents cell production
Chronic radiation: causes DNA mutations that may result in neoplasia
toxins
Depending on chemical, injury may occur in different organs by different mechanisms
microbes
can produce toxin that interferes with cell protein synthesis or cell oxygen utilization
Inflammation and immune reactions
result from cell injury, but may in turn cause injury themselves. Inflammatory cells release digestive enzymes designed to neutralize foreign agents, but also can digest healthy tissue.
Nutritional imbalance
obesity related to CV disease, cancer, DM2
Genetic and metabolic defects
can cause accumulation of abnormal products, which can damage cells,
aging
progressive, mild injury that ultimately leads to cell death
mild injury
atrophy (decreased size and function of cell), hypertrophy (increase size and function of cell), hyperplasia (enlargement of tissue or organ due to more cells), metaplasia (usually reversible - a change from 1 cell type to another due to chronic injury), or dysplasia (disordered growth)
necrosis
pathological death of cells due to injury
apoptosis
programed cell death - cell shrivels and ingested/digested by scavenger cells
Chemical signals to mediate inflammatory process:
injured cells release chemical signals to produce inflammation, reduce consequence of injury, and repair damage
Autocrines: signals that act back on generating cell
Paracrines: molecules released by cells that act on nearby cells
Endocrines (hormones): molecules released into bloodstream to act on distant cells
acute inflammation
short term, first phase of wound healing. Occurs before immune response becomes established to eliminate foreign agent. Occurs in 2 overlapping stages (vascular first and cellular second). Vascular: Arterioles and venules dilate promoting congestion and increase in capillary permeability resulting in cardinal signs of inflammation, as fluid leaves, remaining fluid becomes viscous causing clotting. Cellular: initiated by phagocytic WBC - WBCs adhere to vessel wall and through emigration move through inflamed tissue - chemotaxis causes movement through cells - phagocytosis occurs causing increase in disposed foreign particles, lysis of foreign cells causes exudates resulting in signs of inflammation
chronic inflammation
characterized by abundance of lymphocytes and macrophages, few or no neutrophils, attempted regeneration of destroyed cells, scarring, and rich supply of blood vessels (mix of ongoing inflammation and healing)
wound types:
incision laceration abrasion contusion puncture hematoma penetration
sepsis now mostly caused by…
gram + bacteria