General Pathology Flashcards
What is hypertrophy?
Increased cell size
Due to increased functional demand or hormonal stimulation
Physiological examples for hypertrophy
Sex organs: testosterone and oestrogen during pregnancy
Breast tissue: oestrogen and prolactin for lactation
Uterine muscle: oestrogen during puberty
Skeletal muscle: increased muscle activity (exercise)
Cardiac muscle: sustained outflow increased (athletes)
Pathological examples of hypertrophy
LV cardiac muscle: increased outflow pressure (systemic hypertension, aortic valve disease)
RV cardiac muscle: increased outflow pressure (pulmonary hypertension, pulmonary valve disease)
Arterial smooth muscle: hypertension
What is hyperplasia
Increased cell number due to increase in functional demand, hormonal stimulation and persistent cell injury
Physiological examples of hyperplasia
Breast tissue: oestrogen during puberty, pregnancy and lactation
Thyroid: increased metabolic demand during puberty and pregnancy
Stromal cells in endometrium: oestrogen during puberty
Red cell precursors in bone marrow: erythropoietin at high altitudes
Pathological examples of hyperplasia
Thyroid: Graves autoantibody effect on thyroid
Stromal cells in endometrium: oestrogen, may lead to endometrial carcinoma
Skin: persistent physical trauma (corns)
Skin, larynx, cervix: stimulation of GF in HPV infection
Parathyroid gland: hypocalcemia
Prostate gland
What is metaplasia
Reversible change, one adult cell type replaces another adult cell type
Direct conversion or apparent conversion (respecification of stem cell –> different phenotype of progeny)
Types of metaplasia
Squamous
Glandular
Mesenchymal
Examples of squamous metaplasia
Ciliated pseudostratified columnar –> squamous in smokers/chronic bronchitis pt respiratory tracts
Simple columnar –> squamous in injury/inflammation/pH change in endocervix
Transitional –> squamous in bladder calculi
Examples of glandular metaplasia
Stratified squamous –> simple columnar in Barrett’s oesophagus due to gastroesophageal reflux
Simple columnar –> intestinal in chronic gastritis (H pylori)
Examples of mesenchymal metaplasia
Osseous transformation of old scars
Chondroid
Myeloid: spleen, liver, LN of myeloproliferative diseases
Coagulative necrosis characteristics
Retain outline, normal tissue architecture
Eosinophilic cytoplasm
Chromatin clumping, pyknosis/karyolysis/karyorrhexis
All solid organs except brain
Liquefactive necrosis characteristics
No residual tissue architecture
Necrotic area is semi-fluid
Infarct of cells in CNS
Fat necrosis characteristics
Digestive enzymes act on adipose tissue to release FA precipitate
Pancreatitis, breast injury etc
Areas with intra-abdominal/subcutaneous fat
Caseous necrosis characteristics
Necrotic cells do not retain outline or tissue architecture
Dead cells persist as amorphous material, gray-white/soft/cheese-like necrosis
TB lesion in LN, has granuloma
Fibrinoid necrosis characteristics
Highly eosinophilic wall
Plasma proteins accumulate in BV wall
E.g. hypertension –> increase permeability to proteins –> damage to vessel walls
BV involved in immune reactions
Describe apoptosis
Programmed tiny and silent cell death, induced by intracellular programme
Cells activate enzymes to degrade cell contents, rapidly phagocytosed by neighboring cells without inflammation
> initiation phase: extrinsic and intrinsic pathways activate caspases
> execution phase: caspases mediate proteolytic cascade
Examples of apoptosis
Physiological:
Endometrial breakdown during menstruation
In embryogenesis to prevent malformation
Killing DNA damaged cells to prevent mutations and cancer
Killing virus/infected cancer cells
Pathological:
Atrophy of parenchymal tissues after duct obstruction