Pathology Flashcards
The 3 major definitions of pathology are:
- The scientific and medical discipline (science) that studies the functional, molecular, and functional manifestations of disease, and the mechanisms that cause disease. 2. The structural and functional manifestations of a disease. 3. A disease.
Role of pathologists in a research setting
Pathologists advance knowledge and understanding of disease
Role of pathologists in a clinical setting
Pathologists apply knowledge and understanding of disease to optimize prevention, diagnosis, and treatment of disease.
What is a disease?
Molecular, cellular, tissue, organ, and organismic damage caused by an etiology and mediated by pathogenic mechanisms.
Where do we target prevention and treatment of disease?
Etiology (cause) Pathogenesis (mechanism of disease)
VINDICATE nemonic
V-vascular I-inflammatory N-neoplastic D-drug/toxin I-infectious C-congenital/genetic A-autoimmune/immune T-traumatic/physical E-endocrine/metabolic/nutritional
Diagnosis:
The name for a disease
Etiology:
The cause of disease (many categories: infections, physical, chemical, genetic, immune, etc.)
Pathogenesis:
The sequence of events that leads from the etiology to the manifestations of the disease
Symptom:
Disease manifestation perceived and reported by the patient
Sign:
Manifestation of disease that can be identified by physical examination, laboratory tests, imaging studies, and other methods
Differential Diagnosis:
A ranked list of the most likely diagnoses based on the signs and symptoms of disease in a given patient.
Hypertrophy:
increased size of cells
Hyperplasia:
Non-neoplastic increase in the number of cells in an organ or tissue
Atrophy:
Reduced size of cells or organs
Metaplasia:
A conversion of one differentiated cell type to another
Dysplasia:
Disordered growth and maturation of the cellular components of a tissue. Dysplasia may be a precursor to malignant neoplasia.
Neoplasia:
The autonomous growth of cells that have escaped normal regulation of cell proliferation. Neoplasms that remain localized are termed benign, whereas those that spread (or are capable of spreading) to different sites (metastasize) are termed malignant.
7 Causes (etiologies) of Atrophy:
- Reduced functional demand (e.g. skeletal muscle atrophy caused by denervation) 2. Inadequate oxygen supply (e.g. kidney atrophy caused by renal artery stenosis) 3. Insufficient Nutrients (e.g. skeletal muscle and fat atrophy caused by starvation) 4. Interrupted Trophic Signals (e.g. endometrial atrophy after menopause) 5. Persistent Cell Injury (e.g. gastric mucosal atrophy caused by chronic gastritis) 6. Increased Pressure (e.g. localized skin atrophy caused by prolonged bed rest) 7. Chronic disease (e.g. cachexia caused by chronic disease)
Apoptosis:
Cell death caused by activation of internal molecular pathways leading to cell death. Can be physiological (epithelial sloughing before renewal) or pathological (hepatitis virus-induced hepatocyte loss)
Necrosis:
Cell death caused by pathological lethal injury that often originates outside the cell (e.g. injury by hypoxia, inflammation, molecular toxin, burn, etc.)
How is cell death histologically demonstrated?
Nuclear changes
Pyknosis:
The nucleus becomes smaller and stains deeply basophilic because of chromatin clumping
Karyorrhexis:
The pyknotic nucleus breaks up into many smaller fragments
Karyolysis:
The nucleus may be extruded from the cell or have progressive loss of chromatin staining resulting in the disappearance of the nucleus
Coagulative necrosis:
Nuclei disappear (karyolysis) and cytoplasm becomes more homogenous (and often more acidophilic) resulting in residual ghosts of cells with no nuclei. (e.g. can emerge with MI with ischemic coagulative necrosis)
Gross features:
e.g. localized discoloration of the myocardial tissue caused by ischemic necrosis
Histologic features:
e.g. localized discoloration on the myocardial tissue with loss of myocardial cell nuclei (karyolysis)
Liquefactive necrosis:
Rapid dissolution of cells that liquefies the necrotic tissue. Most often caused by intense localized infiltration of neutrophilic polymorphonuclear leukocytes (neutrophils) at sites of severe acute inflammation (e.g. caused by bacterial infection). Localized acute inflammation with liquefactive necrosis is called an abscess.
Caseous Necrosis:
Necrosis caused by tuberculosis with a marginal zone of aggregated macrophages and a central zone of necrosis containing amorphous debris derived from necrotic hose cells and necrotic mycobacterial cells. The nodular gross lesions are called granulomas and the dense infiltrates of macrophages granulomatous inflammation.
Fat necrosis:
Specifically affects adipose tissue and most commonly results from pancreatitis or trauma resulting in the release of lipases that free up fatty acids that bind calcium to form calcium soaps (saponification).
Tissue response to injury:
Begins with etiology Cell/issue injury Acute inflammation Chronic inflammation Repair (regeneration and/or fibrosis) *not every injury results in the full spectrum of responses
Inflammation:
A reaction of tissue to a pathogenic insult. Mediated by extracellular molecular signals that activate humoral and cellular inflammatory pathways, and cause the movement of fluid and leukocytes from blood into the extravascular compartment
Result of inflammation:
-Localizes or eliminates the cause of injury -Removes injured tissue components -Leads to repair *Inflammation is a double-edged sword that usually is beneficial but can cause morbidity and mortality.
Five cardinal signs of acute inflammation:
- Rubor (redness) 2. Tumor (swelling) 3. Calor (heat) 4. Dolor (pain) 5. Functio Laesa (loss of function)
Acute inflammation:
Has densely packed polymorphonuclear neutrophils (PMNs) with multi-lobed nuclei -Vasodilation resulting in increased blood flow causing redness and transudation of fluid causing edema. -Activation of humoral mediators, causing pain, exudation of plasma proteins, and transmigration of neutrophils. -Influx of numerous mononuclear leukocytes (lymphocytes, monocytes, macrophages, plasma cells) -Increased extracellular matrix (collagen)
Chronic inflammation:
has mononuclear leukocytes, monocytes, macrophages, and plasma cells
Transudate:
ADD
Exudate:
ADD
Mononuclear leukocytes:
lymphocytes, monocytes, macrophages, plasma cells
Hemosiderin
ADD