Module 4 L1-2 Flashcards
How cells respond to injury
Homeostasis, Adaptation, Cell injury, Cell Death
Hypertrophy definition
Increase in size
Hypertrophy occurs in what cells
Cells incapable of dividing - striated cells skeletal muscle and heart
Hypertrophy causes
Increased workload, uterus in pregnancy, hypertension, aortic valve, adrenergic hormones, stretching
Hyperplasia definition
Increase in number
Hyperplasia physical examples
Boob growth, compensatory hyperplasia (regeneration of liver)
Hyperplasia pathologic examples
excessive hormonal growth or growth factor stimulation, hyperplastic tissue may eventually become malignant
Atrophy definition
decrease in size
Atrophy causes
Decreased workload, loss of innervation, reduced blood supply, inadequate nutrition, aging, increased protein degradation, reduced protein synthesis
Metaplasia definition
one adult cell type is replaced by another, reversible change
Metaplasia examples
Ciliated cells in trachea to clear mucous, in smokers baretts esophagus
Cancerous cell adaptations
Metaplasia, Dysplasia, Hyperplasia
Dysplasia definition
Vary in size, shape, number, organization
Dysplasia examples
chronic irritation and inflammation, metaplastic squamous epithelium in respiratory tract and uterine cervix, reversible, pap smear
8 Causes of cell injury
Oxygen deprivation, chemical agents, infectious agents, immunological reactions, genetic defects, physical agents, nutritional imbalances, aging
Hypoxia
inadequate oxygenation of blood (pneumonia)
Ischemia
loss of oxygen supply
Astherosclerosis
blockage of coronary arteries
Aging
accumuation of damage by ROS loss of telomerase function
Ischemia death times
Non contractile 1-2min
Cell death 20-30min
Dead by electron microscopy 2-3hrs
Dead by light microscopy 6-12hrs
Mechanisms of Cell injury
atp deletion, mitochondrial damage, membrane damage, calcium influx, increased ROS
How to increase calcium influx
release from intracellular calcium stores or calcium influx across plasma membrane
Plasma membrane damage
loss of osmotic balance, influx of fluids and ions
Lysosomal membrane damage
leakage of enzymes into the cytoplasm and activation of acid hydrolases in acidic intracellular pH of the injured cells
Increased ROS leads to
Damaged lipids, proteins, DNA can break, abnormal folding, mutations
Necrosis definition
Swell, rupture, and burst
Apoptosis
cells destined to die enzymes incapable of degrading cells own dna, programmed destruction, dna damage, accumulation of misfolded proteins
Intrinsic apoptosis pathway
Injury stressor injury to bcl2
Extrinsic apoptosis pathway
receptor engaged by ligand
Reversible cell injury leads to
necrosis
Characteristics of reversible injury
Cellular injury and fatty change
Characteristics of irreversible injury
Mitochondrial dysfunction and membrane dysfunction
Mechanisms for OFRs and ROS
Superoxide dismutase, glutathione peroxidase, catalase, antioxidants, sequestration of free ionized iron and copper
Defects in membrane permeability
mitochondrial membrane damage, plasma membrane damage, lysosomal membrane damage
