PPY Ch 3 and 4 Learning Objectives
Understand the difference between physiologic and pathologic adaptation, and learn which cell types undergo hypertrophy and which undergo hyperplasia.
Labile cells undergo hyperplasia (number increase) Stable cells undergo hypertrophy (size increase)
Describe the role of molecular procedures in the diagnosis and treatment of disease.
Molecular tests are becoming more common - rapid and give more sensitive results molecular diagnosis determines the molecular signature of neoplasms or microorganisms, involves sequencing DNA/RNA and coupling it with a probe, sequencing is done by a PCR
Identify the tests or procedures performed by radiologists, anatomic pathologists, and clinical pathologists.
radiologic - xray, CT, ultrasound, nuclear medicine AP's - surgical pathology, biopsy, resection, cytology, FNA, autopsy, forensics, etc CP's - biochemical tests, urinalysis, blood tests, transfusion medicine, immunopathology, microbiology labs, molecular testing, PCR tests
Name the strategies that healthcare practitioners use to detect and diagnose symptomatic disease, asymptomatic disease, and potential disease.
biochemical tests, lab tests, autopsy, forensics, biopsy, resection, cytology, FNA, blood test, urinalysis, physical examinations, etc
List the modifiers of inflammation and repair.
1. Virulence of the infective organisms: For example, staphylococcal bacteria are more capable of destroying tissue than alpha-streptococci. 2. Advancing age: Elderly people heal more slowly than younger people, for various reasons. 3. Poor nutrition: Protein and vitamin C are needed to produce collagen. 4. Diabetes: Small blood vessels are abnormal in diabetics and consequently they do not effectively deliver nutrients to healing tissue. 5. Steroid therapy: Steroids inhibit the inflammatory response by preventing vascular permeability, hindering cellular digestion of de
Understand the pathogenesis and clinical implications of adaption.
Adaptation is the ability of cells to adapt to new physiologic conditions May involve hyperplasia, hypertrophy, and/or atrophy -Labile cells undergo hyperplasia (number increase) -Stable cells undergo hypertrophy (size increase)
Understand what determines whether repair is by regeneration or fibrous connective tissue repair. Understand the sequence of each and how the outcomes differ.
FCTR - scarring or fibrosis Regeneration - replacement of the destroyed tissue by cells similar to those previously present - that is, the parenchymal cells of the organ are reconstituted (more desirable bc function is restored)
Distinguish healing by primary union from healing by secondary union.
Primary union - The best example of repair by primary union is that which follows a clean surgical incision of the skin in which there is minimal tissue damage and the edges of the wound can be closely approximated by tape or sutures. In this example, the narrow space between the two wound edges fills with a small amount of serum, which quickly dries and clots, forming a scab. Within 1 to 2 days, the narrow zone of acute inflammation at the wound edges lessens and new capillaries begin to bridge the gap across the defect. By this time, the epithelium has already grown across the surface of the gap. Within a few more days, fibroblasts grow across the subepithelial portions of the wound and begin to deposit collagen, which eventually contracts, pulling the wound edges together and giving them strength. Although this incision may appear well healed by about 2 weeks, it may take a month or more for the strength of the scar tissue to approximate that of the original tissue. Secondary union - Repair by secondary union uses the same basic process as primary union, except that there is greater injury with consequent greater tissue damage and more inflammation to resolve (Figure 4-30). To fill the void left by tissue damage, there is a tremendous proliferation of capillaries and fibroblasts, which actually start growing after the injury is just a few days old, while acute inflammation may still be intense. After a week or more, the wound will be filled with granulation tissue. This eventually is replaced as more and more collagen is deposited by fibroblasts. Fibroblasts and collagen have inherent contractile properties, which aid in shrinking a wound and drawing the edges together. It may take a long time for a wound that heals by secondary union to achieve strength approximating that of the normal tissue. If a skin wound is very large, the epithelium may never completely bridge the wound, and skin may need to be grafted to the wound site from another area of the body. Transplanted skin usually grows quite readily in such a situation because the underlying granulation tissue is so rich in capillaries. One of the greatest impediments to healing and repair of a wound is the amount of dead tissue and foreign material (e.g., dirt, bacteria, shrapnel) present. The presence of bacteria in a wound may produce necrotic tissue and inflammatory cells as quickly as they are removed. For this reason, the medical care of a large wound should always include thorough cleaning and debridement (removal of foreign material and necrotic tissue).
Define symptomatic disease, asymptomatic disease, and potential disease.
Sympto- most diagnoses can be made from detailed history, physical examination... most diseases are chronic and have a poor outcome if not treated in initial stage Asympto- diagnosing disease early requires regular appointments/screenings Potential- preventative medicine Ex: smallpox, measles, pertusis, periodontal disease
Compare acute inflammation, chronic inflammation, and granulomatous inflammation in terms of cause, histologic appearance, and manifestations.
The treatment of acute inflammation, where therapy includes the administration of aspirin and other non-steroidal anti-inflammatory agents, provides relief of pain and fever for patients. In contrast, chronic inflammation lasts weeks, months or even indefinitely and causes tissue damage. Granulomatous inflammation occurs in response to certain indigestible material and involves an element of cell-mediated immunity. T-lymphocytes become sensitized to the offending agent and recruit large numbers of macrophages that engulf the antigenic agent. These macrophages are called epithelioid cells because their abundant cytoplasm and close approximation to each other in aggregates make them resemble epithelial cells
Necrosis versus Apoptosis
apoptosis is a form of cell death that is generally triggered by normal, healthy processes in the body, necrosis is cell death that is triggered by external factors or disease, such as trauma or infection
Understand the difference(s) among hyperplasia/hypertrophy, atrophy, metaplasia, and dysplasia.
metaplasia - one adult cell type replaces another, can be physiologic or pathologic hyperplasia - increase in number hypertrophy - increase in size dysplasia - abnormal development of cells within tissues/organs
Describe how chemical mediators, including cytokines and chemokines, control the acute inflammatory response.
promote and control inflammatory reaction - histamine to causes vascular dilation, molecules on endothelial cells and leukocytes to mediate margination of leukocytes in area cytokines -Tumor necrosis factor (TNF), IL-1, IL-8, and IL-6: •Increase leukocyte adhesion to endothelium •Increase blood coagulation properties •Stimulate further production of prostaglandins •Elicit fever and neutrophilia •Increase sleep and decrease appetite
List the sequence of events in a typical acute inflammatory reaction.
vascular phase - vessels at injury site dilate and leak, mast cells stimulated to release histamine, blood flow within vessel becomes sluggish, vessels become leaky, causing edema cellular phase - leukocyte (primarily phagocytes) move to injury site and activate, marginated leukocytes adhere to endothelial cells, emigrate into tissue, and move to injury site thru chemotaxis neutrophils - migrate fastest and accumulate over hours, particularly important in bacterial infections, rapidly clear agent by phagocytosis, neutrophils die as they phagocytose and degrade foreign material, lysosomal enzymes and oxygen derived free radicals damage surrounding tissue, dead neutrophils, digested tissue, and degraded bacteria remain to from pus Macrophages - arrive later and and hardier than neutrophils, carry major cleaning load in inflammatory debris amount of neutrophils and macrophages depend on nature of dead tissue, amount of dead tissue, presence of chemotactic foreign substances
Explain how abscesses, cellulitis, and ulcers differ in gross appearance and location within the body.
•Abscess -Localized collection of pus -Usually well-demarcated and spherical -Most commonly caused by pyogenic bacteria -Examples: boils, paronychia, and comedones -Typically red, hot, swollen, and painful -Require lancing and draining •Cellulitis -Spreading acute inflammatory process -Common with streptococcal bacterial infections -Caused by body's inability to confine organism -Seen in skin and subcutaneous tissue -Characterized by nonlocalized edema and redness -Related condition is necrotizing fasciitis •Ulcer -Local excavation of epithelium -Epithelium usually damaged by combination of injurious agent and acute inflammatory response -Common in stomach and duodenum -Bedsores are another example
Explain the role of the primary care physician, medical specialist, radiologist, pathologist, and public health laboratory in diagnosing diseases.
•Primary healthcare practitioners may: -Perform common tests such as urinalysis, vaginal smears, and throat cultures -Procure samples sent to laboratory for analysis •Specialists perform: -Manipulative procedures -Procedures requiring specialized equipment
Explain how serous, fibrinous, and purulent exudates differ in composition and gross appearance.
•Serous exudate -Contains fluid and small amounts of protein -Implies lesser degree of damage •Fibrinous exudate -Composed of large amounts of fibrinogen •Purulent exudate (pus) -Loaded with live and dead leukocytes
