Cell Responses to Stress , Adaptation, Injury, Death - Dobson (Ch2) Flashcards
Etiology
Cause
Hypertrophy
Increased size in cells due to increased demand
= increased synthesis of cell proteins and myofilaments
Hyperplasia
Increased number of cells due to higher demand
Metaplasia
The increase in cells differentiated to new role (Change in phenotype), usually when a cell is sensitive to stress and replaced by a cell not as sensitive
Due to Chronic irritation
Reversible
What causes autophagy
Low nutrients
What can cause calcification or intracellular accumulations
Metabolic changes from genetically or acquired
Or Chronic Injury
what causes either the physiologic or pathological hypertrophy to activate
TGF-B, ,IGF-1, (a-adrenergic agonist, endthelin, angiotensin = vasoconstriction)
What are the factors activated for Physiologic Hyperplasia
= exercise induced
(PI3K/AKT pathway)
= (uterus grows when pregnant)
What are the factors activated in pathologic Hyperplasia
G-protein receptors and their pathway
What TF are activated to make more myosin and muscle proteins
GATA4, NFAT, MEF2
Cardiac hypertrophy usually is associated with what
Increased ANP production
Physiologic Hyperplasia
H or GFs needed in higher amount after damage or resection, so it can have normal function
(Breasts during puberty, adrenal gland)
Hormonal hyperplasia
Glands like breast growth
Compensatory hyperplasia
Liver
Pathologic Hyperplasia
Excessive H or GFs on target cells due to that cell not responding well
(Endometrial - E does not decrease like it should in period cycle and endometrium continues to grow, Prostate - T continuously stimulating growth)
Physiologic Atrophy
Embryologic and normal things
Pathologic Atrophy
Low workload X innervation X BF Low nutrition or high TNF X endocrine stimulation (endometrium, breasts, vagina) Pressure on the tissue (tumor or bone)
Ex of metaplasia
Columnar to squamous epithelium in the respiratory track (irrigation like smoking, low VIT A, GERD), bile duct, pancreatic duct, salivary glands
Squamous metaplasia can cause what consequence
Low protection, mucus secretion, ciliary actions
Can lead to malignancy
For Cartilage or adipose or bone in muscles and other tissues = CT metaplasia
Bone formation in muscle (metaplasia) called what
Myositis Ossificans
How does metaplasia happen
Reprogramming or stem cells in tissues or mesenchyme cells that are undifferentiated
Hallmarks for reversible cell injury
- Cell swelling (ion changes)
- Reduced oxidative phosphorylation (low ATP storages)
- Altered mitochondria and cytoskeleton
- Light microscopy sees fatty change and swelled cells
Necrosis uses what to die
Lysosomes and cleaned up by inflammation
Necrosis and apoptosis physiologic and pathologic
Necrosis is always pathologic
Apoptosis is both
Necrosis nucleus
Apoptosis nucleus
N : Pyknosis = shrink, Karyorrhexis = fragmentation, Karyolysis = endonuclease degrade and it fades
A : Fragmentation to nucleosomes
What is seen in reversible cell injury
Lowered cell function
Ultra structural changes (mito, PM, ER, Nuclear changes)
What is seen in irreversible cell
- Biochemical alterations
2 . Ultra structural changes - Light microscopic changes
- Gross morphological changes
What is seen in necrotic cell
- High eosinophilia
- Glassy looking
- Myelin figures (phospholipid masses)
- Calcification
Coagulative necrosis
No digestion of cells (only denature proteins)
Ischemia due to obstructed vessel = all organs (except brain)
- if localized = infarct
Liquefaction necrosis
Digests cells - liquid, pus (creamy yellow)
Bacteria or fungal infection
CNS (brain)
Gangrenous Necrosis
Lowe limbs usually from coagulative necrosis, can undergo liquefactive necrosis is bacteria infects it
Caseous necrosis
TB ad fungal infection
= cheese Iike
= Lysed cells, granular debri = granuloma
Fat necrosis
Fat destruction, released pancreatic enzymes (lipases)
Calcium deposits
Fibrinoid necrosis
Immune reactions in BVs
Fibrinoids (fibrin leaks out)
In low ATP levels like from hypoxia
Body depends on anaerobic glycolysis from glycogen stores = lactic acid
Irreversible Mitochondrial and lysosomal damage causes
Necrosis