Exam 1 Flashcards
Define Pathology
The study of disease. The study of suffering and illness. Study of structural and functional changes in cells, tissues, and organs of the body that are cause or are caused by disease.
Define Disease
The pattern of response of living organism to injury. When cells fail to adapt to the injury or the adaptive mechanism itself becomes harmful, disease results.
Define Signs
Objective evidence of disease (e.g. blood in stool). May also be called physical sign.
Define Symptoms
Subjective evidence of disease (e.g. “I am having abdominal pain”). Described by the patient. Also called clinical symptoms (e.g. pain, dizziness, nausea).
Define Etiology
The cause of a disease process (e.g. lung cancer can be caused by smoking - this is the etiology of lung cancer). Also include biologic agents, chemical agents, or physical forces.
Define Pathogenesis
The development of a given disease. The sequence of cellular events that take place from time of initial contact until expression of the disease. The mechanism of how a disease evolves until it becomes manifest (e.g. smoking causes a coating in your lungs, which gets into the DNA of the lung cells and causes mutations which cause cancer).
Define Manifestations
The changes in structure and function of tissues, organs and system characteristic of disease (both gross anatomic and microscopic changes).
Define Sequelae and Complications
The secondary consequences of a disease.
Define Prognosis
The anticipated course of disease and final outcome (cure, remission, morbidity or mortality)
Define Epidemiology (incidence and prevalence).
The study of disease in population. Within populations we can look for patterns in disease or study risk factors that predispose to disease.
The incidence represents the number of new cases arising in a population over a given time period, and prevalence is the total number of cases (new and existing cases) of the disease in a given population.
Define Morbidity
Illness that impairs the well-being and normal function of a patient (living with disease).
Define Mortality
Illness causing the death of a patient (death from disease).
What was the leading cause of death in Canada in 2018?
Cancer
What are the two categories of disease causes, explain:
Genetic causes: inherited genetic defects.
Environmental causes: exposure to cause of disease
*Diseases result from a variable interaction between the host (i.e. genetic and environmental factors).
Define Iatrogenic
Complications (adverse event) from treatment. Unintended injuries, or complications resulting in death, disability or prolonged hospital stay that arise from health care management.
Define Idiopathic
Of unknown etiology (cause of disease).
What are the different categories of environmental causes of disease? Give examples of each.
- Physical agents: mechanical trauma (e.g. cuts), temperature (e.g. burns, frostbite, heatstroke), electrical burns (e.g. lightning), radiation, atmospheric pressure (e.g. deep water diving).
- Chemical agents: environmental or industrial exposure (e.g. asbestos), poisons/ toxins, drugs, iatrogenic disease, infections, and allergens.
List the current techniques of pathology
Gross pathology, light microscopic examination and electron microscopy, immunohistochemistry, and molecular testing.
Describe gross pathology
Technique which looks at the big picture, e.g. a whole organ, tissue, etc. Visual observations and descriptions (naked eye examination)
Describe light and electron microscopy
Look at sections under a microscope (standard stains: hematoxylin - blue : stains DNA / nucleus, eosin - pink : stains extracellular matrix and cytoplasm
Describe immunohistochemistry
Investigations of disease at the cellular level (e.g. shows a specific protein) - primary antibody recognizes antigen, then secondary antibody recognizes primary antibody - HRB on secondary antibody turns brown (stain = dab).
Describe molecular testing
Analysis of DNA, RNA and protein. Sequence genes. Investigation of disease at the molecular level. e.g. chromosomal analysis.
What does alternative classification of disease mean?
What are the alternative classifications?
More detailed classification of disease based on the pathogenesis or disease process.
-Injury
-Inflammation
-Infection
-Immunological reaction
-Neoplasia
-Metabolic or endocrine
-Nutritional
-Vascular disease
-Psychological factors
Describe injury alternative classification of disease
Due to physical or chemical agent(s). At the cellular level, injury injury may be reversible and the cell/ tissue survives or adapts (atrophy, hypertrophy, hyperplasia), or irreversible leading to the death and degeneration of the cell.
Describe inflammation alternative classification of disease
The inflammatory response is common to many diseases (injury, etc.) but some diseases are thought to be primarily inflammatory (e.g. tonsillitis or acute apendicitis). A chronic inflammation response may also occur in certain allergic-type reactions and with certain viral or parasitic infections.
Describe infection alternative classification of disease
One of the most common forms of disease, infection usually produces mild to moderate symptoms. Infectious organisms (viruses, bacteria, parasites) can produce more serious illness in those whose immune systems are compromised. Cellular pathology depends on factors of both the attacking organism and the host’s response.
Describe immunological response alternative classification of disease
The immune response is normally protective, but in some circumstances the reaction may become excessive (e.g. hypersensitivity to allergens - anaphylactic shock) or may act against the body’s own cells (e.g. autoimmune disease) or may be absent or depressed (immunodeficiency, immunosuppressive therapy).
Describe neoplasia alternative classification of disease
Autonomous (on its own- in control) proliferation of cells, usually causing tumours or masses. These can be benign (will not spread) or malignant (can spread- metastasize). Latter more likely to kill patient.
Describe metabolic or endocrine alternative classification of disease
Disorders of enzymes, hormones, or secretory products (e.g. type 2 diabetes). Some metabolic diseases are genetic (e.g. congenital adrenal hyperplasia).
Describe nutritional alternative classification of disease
Deficiencies in proteins or calories due to insufficient supply (e.g. anorexia nervosa, kwashiorkor, marasmus), decreased absorption, transport or utilization (e.g. celiac disease) or specific vitamin or mineral deficiencies (e.g. scurvy). The flipside, excess calories or obesity is also a nutritional disease and can increase morbidity due to the increased risk of a number of conditions (e.g. hypertension, diabetes, atherosclerosis, heart attacks, and some cancers).
Describe vascular disease alternative classification of disease
One of the most common causes of death in developed countries. Narrowing of important blood vessels (atherosclerosis) underlies very common causes of morbidity and mortality as heart attacks and strokes.
Describe psychological factors alternative classification of disease
Psychological factors may both cause and effect disease processes. Psychological stress may lead to mental illness or worsen the existing somatic disease. Psychological factors are also an important factor in disease caused by addiction (drugs, alcohol, cigarettes, etc.)
What are the different causes or agents of cell injury?
-Physical: trauma, radiation, temp, changes in pressure
-Chemical: air pollutants, CO, pesticides, poisons, toxins, drugs
-Biological: infectious organisms, biological toxins
-Nutritional or metabolic: nutrient deficiencies / excesses, ischemia, lack of adequate blood supply - hypoxia
-Immune reactions: allergens, autoimmune disease
-Genetic defects: single gene disorders (sickle cell disease, hemophilia), chromosomal abnormalities (trisomy 21)
-Cellular aging: loss of normal repair mechanisms
Define adaptation
Adaptation can include regulation of cells receptors (up and down regulation), or changes in protein synthesis or turnover. In all cases of adaptation, if the stimulus is removed, the cells will revert back to their resting state.
What are the different types of adaptation?
Atrophy
Hypertrophy
Hyperplasia
Metaplasia
Describe Atrophy, what are the causes?
Decrease in mass due to decrease in cell size (decreased function).
-Due to decreased blood supply (ischemia), or nutritional and trophic factors.
E.g. can result from decreased workload (immobilization of limb, disuse), loss of innervation, diminished blood or nutrient supply, loss of endocrine or hormonal stimulation (interruption of trophic signals), and aging.
What is a physiological and pathological example of Atrophy?
Physiological: occurs in normal aging (shrinkage and loss of brain cells with age)
Pathological: disuse of skeletal muscle in immobilized limbs or denervation atrophy following loss of nerve input to a muscle.
Describe Hypertrophy
Causes?
Increase in cell size (increase synthesis of cellular protein and structural components and organelles - increased contents).
Accompanied by an augmented functional capacity.
Causes:
-increased functional demand (myocardial hypertrophy in hypertension, muscle hypertrophy in athletes)
-Physiologic (hormonal) hypertrophy - sex organs at puberty
Describe Hyperplasia
Causes?
Increase in number of cells in an organ or tissue caused by cell division.
Causes:
-Increased functional demand (increased RBCs in high altitude)
-Hormonal stimulation (endometrium in early phase of menstrual cycle)
-Persistent cell injury (skin in calluses)
What is a physiological and pathological example of Hypertrophy and Hyperplasia?
Often hypertrophy and hyperplasia occur together (can be separate as well tho). They are considered the opposite of atrophy.
Physiological: Uterus in pregnancy undergoes hypertrophy and hyperplasia to adapt and grow in order to contain a fetus.
Pathological: endometrial hyperplasia - unopposed estrogen, endometrial lining thickens and keeps going (menopause), keeps replicating out of control and can lead to endometrial carcinoma.
Describe Metaplasia
Change /conversion of one differentiated cell type into another. May result in decreased function or increased chance of malignancy. Often due to longterm exposure to unsuitable environments.
*protective mechanism but may have loss of function.
What is an example of metaplasia?
Respiratory epithelium in the bronchi exposed to debris on inhalation, cilia move it out of lungs but very small and can get overwhelmed - e.g. from smoking. Cells (ciliated columnar) are replaced by squamous cells (which lines your mouth - very tough). Now have no cilia to get rid of debris or smoke. Cells become dysplastic and then malignant (pathological).
Hyperplasia and metaplasia can both lead to dysplasia.
What is Dysplasia? What are the features of Dysplasia?
*What is the significance?
Alteration in size, shape, and organization of the cellular components of a tissue.
Broad term to describe the abnormal development of cells within tissue or organs.
Features:
-variation of shape and size of cells (cellular pleomorphism)
-variation in nuclear shape and size (nuclear pleomorphism)
-enlargement, irregularity and hyperchromatism of the nuclei
-disordered arrangement of the cell
*significance: dysplasia is a pre-malignant lesion
Contrast reversible vs irreversible cell injury
Cells lose functional activity relatively quickly as a result of biochemical derangements, while morphological changes of cell injury and death lag far behind.
-At early stages, mild forms of injury and functional/ morphological changes are completely reversible if stimulus is removed (has not progressed to severe membrane or nuclear damage yet).
-With continuing damage, cell injury becomes irreversible; the cell cannot recover and dies.
Describe reversible injury. What are the cellular changes that characterize reversible cell injury?
Injury caused by a variety of agents produces a characteristic cellular or hydropic swelling (increase in cell volume, characterized by a large, pale, and vacuolated cytoplasm and a normally located nucleus) when seen under a microscope. This swelling results from impairment of the process that controls ion concentrations in the cytoplasm. With removal of the stimulus, these changes are reversible and the cell reverts back to its normal state.
Describe irreversible injury.
If overwhelming injury occurs or occurs at a rate at which the cell cannot adapt, necrosis or cell death is the result. With continuing damage, cell injury becomes irreversible.
Describe the cellular changes of irreversible cell injury leading to necrosis
Irreversible changes include: membrane rupture, dispersal of organelles, breakdown of lysosomes, and activation of inflammatory response.
Types of irreversible responses include: interruption of membrane integrity; hydrolysis of phospholipids, proteins and nucleic acids; and necrosis, where organelles undergo a sequence of changes.
List the different types of necrosis
Coagulative necrosis - Gangrenous necrosis
Liquefactive necrosis
Fat necrosis
Caseous necrosis
Fibrinoid necrosis
Describe coagulative necrosis. Where is this typically found?
Most common form. Microscopically all the changes of necrosis are seen (eosinophilia, pyknosis, karyorrhexis, and karyolysis). Cells appear like “ghosts” of themselves in which the basic structural outline of the coagulated cell persists for a number of days, nucleus is gone though.
Typical of ischemic injury. See in heart and kidney because they have areas that are fed by one blood supply. If this supply is cutoff - get coagulative necrosis. Tends to be firm.
What is eosinophilia?
Pinkness
What is pyknosis?
Pyknosis, or karyopyknosis, is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis.
Shrinkage
What is karyorrhexis?
Karyorrhexis is the destructive fragmentation of the nucleus of a dying cell whereby its chromatin is distributed irregularly throughout the cytoplasm. It is usually preceded by pyknosis and can occur as a result of either programmed cell death, cellular senescence, or necrosis.
The pyknotic nucleus fragments
What is karyolysis?
Complete dissolution of nuclear components of a dying cell.
Describe gangrenous necrosis
“Wet gangrene” is used to refer to coagulative necrosis (most frequently of a limb) when there is superimposed infection with a liquefactive component.
If the necrotic tissue dries out (with no infectious component) it becomes dark black and mummified and is called “dry gangrene”. Typically in limbs, compromised vascular supply.
Describe liquefactive necrosis. What are examples?
Rapid loss of tissue architecture and digestion of the dead cells. Most often seen in the CNS, lungs or in the presence of bacteria (typical of bacterial damage).
Due to action of hydrolytic enzymes, not firm, more mushy. Can get cavities.
E.g. stroke in the brain, or abscess in the lung.
Describe fat necrosis. What is an example?
Specific to fat (adipose) tissue. Released enzymes digest fat and combines with calcium to form chalky-white deposits.
E.g. pancreatitis (seen most commonly with injury to the pancreas), damage to breast tissue
Describe caseous necrosis. Example?
Soft, friable, ‘cheesy-like (goat cheese - crumbly)’ material.
Characteristic of tuberculosis - airborn pathogen, goes into your lung, body tries to break it down, see accumulation of macrophages - trying to eat it up.
Describe fibrinoid necrosis
Blood vessel wall gets so damaged that it is replaced by fibrid.
Define Apoptosis. Give physiological and pathological examples.
Energy-dependent process specifically designed to switch off unneeded of damaged cells and eliminate them. Morphologic manifestation of programmed cell death.
-Physiological: During embryogenesis in shaping fingers and toes; the physiological involution of thymus during development; endometrium during menstrual cycle.
-Pathological: Following radiation injury in some cancer
