Lecture 3 Cellular Injury Flashcards
Dynamic steady state
Body maintains itself at a relatively constant composition
Cell injury
Occurs when cells are exposed to severe stress that no longer allows them to maintain homeostasis which results in structural and functional changes
Cells injury vs cell death
Cell injury is reversible but cell death is irreversible
Basic changes that occur in cell injury
1) dysfunction of NA+/K+ pump
2) loss of plasma membrane integrity 3) defects in protein synthesis ability
4) intracellular accumulations
5) genetic damage
Hypoxia
Deficiency of oxygen
Hypoxemia
Deficiency of oxygen in blood
Ischemia
Local reduction of blood flow (oxygen)
Cyanosis
Bluish coloration of the skin and mucous membrane caused by hypoxia
Infarction
An area of dead tissue to an organ caused by lack of blood flow in that area
Nercrosis
Death of a small area of tissue or part of an organ that is surrounded by healthy tissue
Gangrene
Death of a large portion of tissue
Eschar
Blackened, thick layer of necrotic tissue often seen in Burns and decubiti
Prolonged ischemia
Susceptible to infarction
Causes of death of tissue
- genetic replication errors
- nutritional deficiencies (high LDL)
- Chemical agents
- free radicals
- Physical injuries
- hypoxia
Free radical injuries
Free electron that attracts and attached to membrane and damage them
Highly reactive molecules made by the body during inefficient mitochondrial metabolism
Atrophy
Decrease or shrinkage in size
Due to disuse, loss of hormonal stimulation (paralysis), inadequate nutrition, ischemia, aging
Muscle hypertrophy
Increase in cell size usually due to increase workload
Hyperplasia
Increase in number of cells
Meta plasma
Reversible replacement of one type of cell with another in response to injury (shape changes)
Dysplasia
Abnormal changes in size, shape, and organization of mature cells
Maybe irreversible
Precancerous condition
Cause: chronic stressor in cell environment
Can change to neoplasia
Neoplasia
New growth malignant or benign
Lack normal cell function & don’t work and keep dividing uncontrollably
Anaplasia
- Poor cellular differentiation
- reversion of cells to simpler and less differentiated form
- not reversible
- mostly malignant
Apoptosis
Genetically programmed cell death
Failure of apoptosis
Give rise to certain cancers
Excessive apoptosis
Excessive cell death rates
