Pathology Flashcards
What is hypertrophy and what are three examples?
An increase in the size of cells.
- Physiologic enlargement of uterus during pregnancy
- Chiseled physique of a weightlifter
- Cardiac enlargement occurring with hypertension or aortic valve disease
What is the definition of hyperplasia and what are three examples?
An increase in the number of cells.
- Hormonal - proliferation of glandular epithelium of female breast at puberty and during pregnancy
- Compensatory - residual tissue grows after removal or loss of part of an organ (regeneration of liver)
- BPH
What is atrophy and what are three examples?
Shrinkage in the size of cell by loss of cell substance.
- Immobilization of limb to permit healing of a fracture
- Loss of hormone stimulation in menopause
- Denervation
What is metaplasia and what are three examples?
Reversible change in which one adult cell type is replaced by another.
- In smokers - normal ciliates columnar epithelial cells of lung replaced by stratified squamous
- In chronic gastric reflux - normal stratified squamous of lower esophagus replaced by gastric or intestinal type columnar epithelium
- In soft tissues - in foci of injury
What are the different causes of cell injury?
Oxygen deprivation Chemical agents - can derange osmotic environment Infectious agents Immunologic reactions (autoimmune and allergic reactions) Genetic factors Nutritional imbalances Physical agents Aging
What are the 3 nuclear change seen morphologically in necrosis?
- Karyolysis - basophilia of chromatin my fade (cell is redder)
- Pyknosis - nuclear shrinks into solid, shrunken mass, increased basophilia
- Karyorrhexis - pyknotic nucleus undergoes fragmentation
How can you recognize coagulative necrosis and where does it happen?
Eosinophilic anucleate cells persist
Characteristic of infarcts in all solid organs except the brain.
How can you recognize liquefactive necrosis and where does it occur?
Tissue becomes liquid viscous mass.
Seen in purulent infections.
Seen in focal bacteria or fungal infections.
How can you recognize gangrenous necrosis and where does it occur?
Dry or wet gangrene
Seen in a limb, particularly lower leg.
How can you recognize caseous necrosis and where is it found?
Frothy yellow-white appearance of the area. A collection of fragments or lysed cells with amorphous granular pink appearance on H&E.
characteristic in granulomas.
How can you recognize fat necrosis and where is it found?
Grossly visible chalky white areas. Basophilic calcium deposits.
Seen typically with release of pancreatic lipases.
How can you recognize fibrinoid necrosis and where is it found?
Bright pink amorphous appearance.
Seen in immunologically mediated diseases like polyarteritis nodosa.
What are the four principal targets and biochemical mechanisms of cell injury?
- Mitochondria and their ability to generate ATP and ROS under pathological conditions
- Disturbance in calcium homeostasis
- Damage to cellular (plasma and lysosomal) membranes
- Damage to DNA and misfolding of proteins
What are the functional consequences of ATP depletion during cell injury?
- tissues with greater glycolytic capacity (like liver) better able to survive
- activity of pm ATP dependent Na pumps is reduced –> intracellular accumulation of sodium and efflux of potassium –> cell swelling
- increase in anaerobic glycolysis –> intracellular glycogen stores rapidly depleted and lactic acid accumulates
- failure of ATP dependent calcium pumps –> influx of calcium
- prolonged leads to structural disruption of protein synthetic apparatus
How do mitochondria respond to and mediate cell injury?
Failure of oxidative phosphorylation leads to less ATP and eventually necrosis, abnormal OP leads to formation of ROS
What are the major consequences of elevated intracellular calcium levels during cell injury?
Activates phospholipases --> membrane damage Proteases --> breakdown proteins Endonucleases ATPases --> faster depletion Caspases
What do cells use to limit effects of reactive oxygen species?
Superoxide dismutases
Glutathione peroxidases
Catalase
Endogenous or exogenous antioxidants
What are the three mechanisms through which ROS cause cell damage?
- Lipid peroxidation of membranes
- Cross linking and other changes in proteins
- DNA damage
What are some examples of apoptosis under pathological conditions?
Accumulation of misfolded proteins leading to ER stress
Pathologic atrophy in parenchymal organs after duct obstruction
What is the intrinsic pathway of apoptosis?
Sensors of Bcl2 family are activated and in turn activate Bax and Bak, dimerize and form pore in mitochondria, cytochrome c leaks out forms apoptosome with AFAP that activates caspase 9.
bcl2 and Bcl-Xl antagonize Bax and Bak and block apoptosis
What is the extrinsic pathway of apoptosis?
Death rectors are members of TNF receptor family, fas molecules cross linked by fasL on activated T cells and bind adaptor proteins via death domain that activate caspase 8 (can then activate proapoptotic Bid)
What are some examples of intrinsic apoptosis?
Growth factor deprivation
DNA damage
ER stress from misfolded protins
Apoptosis of self reactive lymphocytes
What is an example of extrinsic apoptosis?
Apoptosis of self reactive lymphocytes
Cytotoxic T cell mediated apoptosis
What are the circumstances and morphological appearance of fat accumulations in cells?
- abnormal accumulation of triglycerides in parenchymal cells
- seen most in liver but also in heart, skeletal muscle, kidney, and other organs
- cells have larger vacuoles
What are the circumstances and appearance of cholesterol accumulations in cells?
- phagocytic cells may become overloaded with lipid
- atherosclerosis
What are the circumstances and morphological appearance of protein accumulations in cells?
- seen in kidney
- pink hyaline cytoplasmic droplets
- excess presented to cells or they synthesize too much
What are the circumstances and morphological appearance of glycogen accumulations in cells?
- seen in liver
- frothy appearance
- abnormalities in metabolism of glucose or glycogen
- diabetes leads to it in renal tubular epithelium, beta cells of islets, and cardiac myocytes
When and where does carbon pigment happen?
Blacken draining lymph nodes and pulmonary parenchyma
Air pollutant of urban life
What and where does lipofuscin pigment happen?
Brownish yellow appearance
Accumulations in many tissues especially heart, liver, and brain
Function of age or atrophy
Not injurious but marker of past free radical injury
When and where does melanin pigment happen?
Brown black pigment synthesized by melanocytes in epidermis
Adjacent basal keratinocytes can also accumulate it
Protective against uv radiation
When and where does hemosiderin happen?
Hemoglobin derived golden yellow to brown
Accumulate in tissues with local or systemic excess of iron
Small amounts normal in mononuclear phagocytes of bone marrow, spleen, and liver
What is dystrophic calcification and what is an example?
Deposition of calcium in dead or dying necrotic tissues
Serum calcium levels normal
Seen in aorta, large arteries, and aortic valves
End product is formation of crystalline calcium phosphate
What is metastatic calcification?
Can occur in normal tissues with hyercalcemia
Serum calcium is increased
Caused by excess parathyroid hormone, destruction of bone, vitamin d related disorders, and renal failure
What are the three phases of wound healing?
Inflammation
Epithelialization and formulation of granulation tissue
Tissue remodeling (maturation and scar contraction)
What is malformation?
Intrinsically abnormal developmental process, usually multifactorial, risk for recurrence
What is a malformation syndrome?
Recurring pattern of malformation with single underlying cause
Ex: chromosomal abnormality or single genetic mutation
What is disruption?
Secondary destruction of an organ or body region that was previously normal from an extrinsic disturbance, happens later in gestation
Ex: amniotic bands, viral infections, vascular accidents, maternal diabetes
What is deformation?
Extrinsic disturbance of development
Ex: compression of growing fetus
What is a sequence?
Multiple congenital anomalies that result from secondary effects of a single localized abnormality, sporadic or multifactorial inheritance
Ex: oligohydramnios where fetus doesn’t produce enough urine and is compressed
What is symmetric growth restriction and what causes it?
Brain is reduced in size with other organs
Causes are intrinsic to developing fetus - chromosomal abnormalities and fetal infections
What is asymmetric growth restriction and what causes it?
Brain retains normal size relative to other organs
Cause - compromise of uteroplacental blood supply
What are the two ways an infection can reach the placenta or amniotic sac?
Ascending infections - more common, enter through vagina and cervix
Hematogenous infections - enter through maternal bloodstream transplacental