General Pathology Flashcards
What are the 4 aspects of a disease process?
- Etiology - cause
- Pathogenesis - mechanism
- Morphology - appearance
- Functional consequences
What are the possible outcomes of cellular stress?
- Cell adaptation
- Temporary abnormality with recovery
- Permanent structural damage
- DNA damage/mutation
- Cell death
What are the 6 major causes (etiologies) of cellular injury?
- Physical - trauma
- Chemical - drugs, ETOH
- Metabolic - hypoxia, vitamin def, glycemia
- Immunologic - allergy/autoimmunity
- Genetic - chromosomnal abnormality
- Infection - bacteria, virus, parasite
What types of cells are the most susceptible to injury?
Metabolically active cells
What changes can be seen under the light microscope during reversible cell injury?
- Cellular swelling/hydropic change and vacuolization
2. Fatty changes
What is vacuolization?
Small, clear vacuoles within the cytoplasm; these
represent distended and pinched-off segments of the endoplasmic reticulum
Injured cells stain more intensely with: H or E
E – more pronounced and pink with greater injury
The 4 major systems of the cell particularly vulnerable to cell injury:
- Membranes– cell, ER, lysosomes
- Energy production
- Proteins/enzymes (structural+regulatory)
- DNA-nucleus
What is the commonly agreed upon point of no return in cellular injury?
Mitochondrial damage
Often the target of toxic substances, which are not directly toxic, but suffer metabolic activation by target cell, i.e. CCl4
SER
When an injurious agent affects the lysosomes, cell degeneration is said to occur. This can produce:
- Autophagy
- Hereditary absence of enzyme in lysosomes
- Failure degradation phag’ed material
- Liberation and activation of lysosomal enzymes (residual body)
This event plays a central and common role in most pathological contidtions
Lack of oxygen!
What are the 4 main mechanisms (not etiologies) of cellular injury?
- Hypoxia
- Free radicals
- Chemical injury
- Viral injury
Reversible cell changes are known to occur when the duration of ischemia is short and in the following sequence:
- Impaired mitochondria (aerobic respir)
- Dec ATP
- Anaerobic glycolysis
- Glycogen depletion
- Intracellular acidosis with chromatin clumping
Why does cell swelling occur?
Failure of Na/K ATPase pump to keep Na outside
+ accumulation lactate, inorganic phosphate
What happens in reversible cell damage?
Cell swelling, detached ribosomes, blebs, myelin figures (dissociated lipoproteins), mitochondrial swelling
Irreversible injury is characterized by:
- Severe vacuolization of mitochondria
- Damage to plasma membrane
- Swelling lysosomes
- Massive Ca++ influx
What are the biochemical pathways involved in irreversible cell injury?
- Loss of phospholipids (dec. synthesis + breakdown)
- Cytoskeletal alterations (proteases, damaged connections)
- Free radicals
- Lipid breakdown products – free FA’s with detergent character
Once re-oxygenation occurs in a cell so structurally damaged, what happens?
Influx of Ca++ into the cell and mitochondria, phospholipases, proteases, endonucleases, inflammatory mediators
How does the body protect against free radicals?
Antioxidants, catalase, glutathione peroxidase, SOD)
Why are free radicals so dangerous?
Lipid peroxidation, nucleic acid mutations, cross-linking of proteins for degradation
Which is the major organ of lipid metabolism?
Liver
Describe the fatty change of the liver in CCl4 poisoning.
CCl4–>CCl3 in the SER. Lipid peroxidation and cellular swelling; Accumulation of lipid in the ER, inability of the cells to synthesize lipoprotein necessary for triglycerides to leave the hepatic cell
How do viruses affect cells?
Cell death (lysis), cell skeleton (respiratory cilia), fusion of cells, host immunological response
Under routine microscopy, the most recognizable cellular changes include:
Swelling and fatty chagne
Physiological apoptosis includes:
Embryogenesis, hormone-dependent involution, cell deletion, deletion of auto-reactive T cells, tumor growth control
What are the 5 major cell adaptations?
Hypertrophy, hyperplasia, atrophy, metaplasia, dysplasia
T/F Apoptotic cells are seen singly or in small clusters. Bright eosinophilic cytoplasm and condensed, irregular nuclei
T
Accumulation of this agent is associated with cellular aging or senescence.
Lipofuscin
Inflammation is a dynamic process that starts with…. and ends with…
Injury; healing/repair
T/F In order for inflammation to occur, the injury must be non-lethal
T
Differentiate between exudation and transudation
Exudate: has protein
Differentiate between acute and chronic inflammation.
Chronic: lymphocytes
Acute: PMN’s
The most important feature of inflammation is the accumulation of: __________________________.
Leukocytes in the affected tissue
What is rouleaux?
RBC’s become sticky and hence force the WBC’s towards the periphery; aids in margination
Who are the most important chemotactic factors?
Bacterial products, complement fractions, arachidonic acid metabolites, cytokines/chemokines
During phagocytic engulfment, who is the second messenger?
Ca++
The 3 major steps of phagocytosis
- Recognition/Attachment
- Engulfment
- Killing
What are the 5 key characteristics (clinical manifestations) of acute inflammation?
Redness, swelling, pain, heat, loss of function
The 4 major features of acute inflammation:
- Vascular events
- Cellular events
- Phagocytosis
- Mediators of inflammation
The major vascular events in acute inflammation
- Vasoconstriction
- Vasodilation
- Increased vascular permeability
- Increased blood viscosity
Explain the several mechanisms behind increased vascular permeability.
- Histamine – small venules
- Cytokines – cytoskel rearrangement
* *3. Endothelial injury (immediate sustained)** - WBC-dependent
- Vascular endothelial growth factor
Describe the cellular events of acute inflammation.
- Margination- sludging RBC/WBC towards periphery
- Rolling- selectins
- Adhesion- ICAM/VAM
- Transmigration- PECAM
- Chemotaxis- C5a, cytokines, chemokines
What are the 3 major steps of phagocytosis?
- Recognition (opsonization)
- Engulfment
- Killing (ROS)
When leukocytes arrive at the site of cell injury, they will…
- Engulf, degrade, complex bacteria and debris
- Lysosomal enzymes
- Chemical mediators
- Toxic radicals
What is rouleaux?
Peripheral orientation of WBC’s because of sludging of RBC’s; WBC’s pushed towards periphery
LFA-1 is also called
CD11a/CD18
MAC-1 is also called
CD11b/CD18
Who are the first leukocytes to arrive at the site of cell injury?
PMN’s
Liquefactive necrosis
Hydrolysis – BRAIN & BACTERIAL INFECTIONS
Coagulative necrosis
Classic – happens everywhere except the brain
Caseous necrosis
TB/Lung
Fat necrosis
Occurs when lipases are freed; free fa’s released and combine with calcium to form soaps
What are the 5 major types of necrosis?
- Coagulative
- Fat
- Liquefactive
- Caseous
- Gangrenous
Among histamine and serotonin, which is only present in platelets (vs. mast cells/basophils)?
Serotonin
Who are the major cell-derived vascular permeability mediators in inflammation?
- AA metabolites
- PAF
- Amines (histamine, serotonin)
- Endothelins
Who are the major plasma derived chemical mediators of inflammation?
- Coagulation/kinin system
2. Complement
Who is the most important plasma protein system of inflammation?
Complement
Granulomatous chronic inflammation is characteristic of which infections/diseases?
- Infections: TB, syphillis, cat-scratch, fungi, protozoa
- Persistent foreign body
- Rheumatic fever
- RA
- Sarcoidosis
Trace the normal flow of lymphatic fluid
Lymph node –> general circulation –> RES
What are 5 major defects of leukocyte function?
- Number circulating cells
- Adherence
- Migration/Chemotaxis
- Phagocytosis
- Microbicidal activity
What are the 4 major morphological patterns of acute/chronic inflammation?
- Serous
- Fibrinous
- Suppurative/purulent
- Sanguinous
Differentiate between granulomatous and non-specific chronic inflammation
Non-specific: mononuclear cells, C/T, fibroblasts
Gran: R-E, macrophages, giant cells, rim of lymphocytes
Differentiate between granulomatous and non-specific chronic inflammation
Non-specific: mononuclear cells, C/T, fibroblasts
Gran: R-E, macrophages, giant cells, rim of lymphocytes
Define abscess
Localized collection of pus (trypsin overwhelms and destroys damaged tissue)
Define paronychia
Side/Base of fingernail
Define Felon
Anterior portion of distal phalynx (secondary to penetrative wound)
Define empyema
Collection of pus in pleural cavity
Define pseudomembranous inflammation
Toxin/Fibrin/necrotic epithelial cells, WBC’s on mucosal surfaces
Define sinus
Abnormal communication between solid organ/tissue and skin
The 4 organs with the best regenerative capacity
Liver, lung, kidney, spleen
What is the best way to accomplish cell growth in regeneration/repair?
Recruit cells from G0 into the cell cycle
- Growth/stimulation factors
- Loss of growth inhibitor
- Cell-cell; cell-matrix interactions
What is the best way to accomplish cell growth in regeneration/repair?
Recruit cells from G0 into the cell cycle
- Growth/stimulation factors
- Loss of growth inhibitor
- Cell-cell; cell-matrix interactions
The most important cell-cell/cell-matrix interaction in healing involves
Fibronectins (HMW adhesive glycoproteins) which bind to EC components and cell surfaces
Who produces fibronectin?
Fibroblasts, endothelial cells, monocytes
4 Major functions of fibronectin
- Migration of new epithelial cells
- Chemotactic for monocytes, fibroblasts
- Stimulate endothelial cell migration
- Release fibroblast growth factor from monocytes
4 Major functions of fibronectin
- Migration of new epithelial cells
- Chemotactic for monocytes, fibroblasts
- Stimulate endothelial cell migration
- Release fibroblast growth factor from monocytes
What does granulation tissue consist of histologically?
Meshwork of capillaries, fibroblasts, inflammatory cells, ECM
What does granulation tissue consist of histologically?
Meshwork of capillaries, fibroblasts, inflammatory cells, ECM
What is the objective of crust formation?
- Stops bleeding
2. Barrier to infection
What are the 4 major factors influencing the rate of healing?
- Age
- Size of wound
- Secondary infection
- Diet (Vitamin C, D, protein)
What is amyloid? How does it appear under the light microscope? Congo red? Polarized light?
Abnormal ECF proteinaceous deposit
H/E seen as glassy pink; Congo-red: red; Polarized light (apple green)