回帖：Chapter 1 Adaptation and Injury of Cell or Tissue
§1. Cell adaptation and aging
1. Cell adaptation
(1) Atrophy
①Definition: Normal formed organ or tissue diminished in size due to decrease in the size of the parenchymal cells or in the number of cells
②Types: Physiologic atrophy
Pathological atrophy
·Insufficient nutritive atrophy
·Atrophy of disuse
·Denervation atrophy
·Pressure atrophy
·Endocrine atrophy
③Morphologic changes
·Gross appearance: volume↓, weight↓
·Histological changes: Decrease in the size and number of cells
Lipofuscin → brown atrophy (heart or liver)
(2) Hypertrophy
①Definition: an increase in the size of a tissues or organ due to increased size of individual cells
②Types: Physiologic hypertrophy: Pregnancy → uterus↑(endocrine hypertrophy)
Pathologic hypertrophy: Hypertension → heart hypertrophy
GN → residual nephron hypertrophy
(3) Hyperplasia
①Definition: constitutes an increase in the number of cells in an organ or tissue, which may then have increased volume
②Types: Physiologic hyperplasia: Hormonal hyperplasia: SMC of uterus during pregnancy
Compensatory hyperplasia: partial hepatectomy
Pathologic hyperplasia
(4) Metaplasia
①Definition: a process in which one matured cell type (epithelial or mesenchymal) is replaced by another matured cell type
②Types: Epithelial metaplasia
·Squamous metaplasia: Barret esophagitis
·Glandular metaplasia
Mesenchymal tissue metaplasia
2. Cellular aging (senescence)
·Telomerase activity decreasing and telomere shortening
Telomeres: short repeated DNA sequences, ensuring the complete replication of chromosomal ends, protecting chromosomal termini from fusion and degradation
·DNA damage: DNA damage is repaired by endogenous DNA repair enzymes, some damage persists and accumulates
§2. Injury of cells and tissues
1. Causes
·Hypoxia
·Chemical agents and drugs
·Physical agents
·Biologic agents
·Immunologic reactions
·Genetic defect
·Nutritional imbalance
·Others: Endocrine, aging, psychological factor
2. Morphologic changes of cell injury
(1) Reversible injury (Degeneration)
Definition: Morphologic changes of cell or extracellular stromal damage due of metabolic disorder → the deposition of some abnormal substance, excessive normal substance in cell or stroma
·Cellular (hydropic) swelling
The first manifestation of cell injury
①The common site: liver, kidney, heart
②Causes: hypoxia, infection, intoxication
③Pathologic changes: Gross: increased in the weight of the organ
cutting surface pallor in color
capsule tense
section bulgy
cutting edge bulging
LM: cell swelling
fine, red-stained granules within cytoplasm
small clear vacuoles
Ballooned change: clear cytoplasm, cell swelling obviously
EM: Mitochondria and ER swelling
·Fatty change (steatosis)
abnormal accumulations of fat (triglyceride, cholesterol, phospholipid) within parenchymal cells
①The common site: liver, heart, kidney, muscle
②Causes: hypoxia, infection, intoxication, obesity
③Morphology: Gross: enlarged, yellow, soft, greasy
LM: clear vacuoles in the cytoplasm around the nucleus
EM: liposome
Fatty change of myocardium: The common site: left ventricle subendocardium papilary muscle
Tigered effect: apparent bands of yellowed myocardium alterating with bands of darker, red-brown (uninvolved) m