Lecture 25: Cell Adaptation Flashcards
Cells responses to stress and injury
1) Physiological response
- Adaptation to a stimulus within the normal range
2) Pathological responses:
- Adaptation to a stimulus outside normal range
- Can result in cell malfunction, damage, death
- Response depends on
1) Stimulus
2) Duration
3) Magnitude
4) Vulnerability
Cause of cell injury
1) Metabolic
- Hypoxia= Oxygen deficiency
- Ischemia= blood flow deficiency
- Nutritional= def or excess
2) Chemical
- Ex: Drugs/alch
3) Physical
- Trauma
- Extreme tempts
- Radiation
4) Biological
- Virus/bacteria, parasite
5) Immunological
- Allergic rxns
- Autoimmune disease
6) Genetic
- Chromosomal abnormalities
- Mutations
7) Aging
- Cell aging (senescence)
Major intracellular systems affected when cell injury occurs
1) Membrane integrity
2) ATP Production
3) Protein synthesis
4) Genomic or chromosomal integrity
Intracellular systems affects by cell injury (More important)
1) Membrane integrity (Damage)
- Plasma membrane
- Organelles
2) ATP Production
3) Protein synthesis
4) Genomic or chromosomal integrity
Kinds of injury
- Reversible
- Irreversible
Reversible= mild, can recover/regain function
Irreversible= severe
- Membrane damage
- DNA damage
- Cell death (Necrosis/apoptosis)
Early cellular response to injury
- Mild damage to cell
- Cell degeneration
- Reversible
1) Cloudy swelling (pale staining, due to swelling of organelles)
2) Hydropic degeneration (Swelling continued, vacuoles appear in cytoplasm)
3) Fatty Change (accumulation of triglycerides in cytoplasm)
- most common in liver
- common cause= toxins/alch
Cell adaptation to Nonlethal injury:
1) Atrophy
2) Hypertrophy
3) Hyperplasia
4) Metaplasia
1) Atrophy- Decreased size/function in cell
- Ex: Losing weight
- Reversible
- Causes: Decreased functional demand, decreased blood supply, loss innervation, loss of endocrine stimulation, nutritional deficient, aging
- Common tissues effected:
1) Testis (elderly)
2) Skeletal muscle
3) Brain (Neurodegenerative/aging)
2) Hypertrophy- Increase in size of cell
- Ex: gaining weight
- Cells never increase in #
- Can increase organ size
- reversible
- Cause: hormone, increased functional demand (bigger muscles to lift more weight)
- Common tissues effected:
1) cardiac muscles (only thing that can affect cardiac muscles)
2) Skeletal muscles
3) Uterus (pregnancy)
3) Hyperplaisa- Increase in number of cells
- reversible
- Cause: hormone, increased functional demand
- Common tissues effected:
1) Endometrium
2) Prostate gland
3) RBC
4) Glandular Epithelium of breast
5) Uterine enlargement
4) Metaplaisia- Change in differentiation
- Ex: Cancer, esophagus: stratified squamous epithelium transforms to stratified squamous epithelium
- Reversible
- One cell type is replaced by another cell type
- Cause: Adaptive response to environmental stimuli (Ex: cigs smoke, acid reflux)
- Common tissues effected:
1) Respiratory epithelium
2) Cervical epithelium
3) Esophageal epethelium
- Increased risk for dyplasia and neoplasia
Atherosclerosis
Narrowing of renal artery (Kidney atrophy)
Atherosclerotic Cerebrovascular disease
brain atrophy (eldery male)
Can see by bigger spacing in between fissures
Involution
- Organ shrinks/returns to normal
- Usually occurs after stimulus is removed
Dyplasia
- Failure of differentiation and maturation
1) Cellular atypia - Structurally abnormal
- High nuclear to cytoplasm ratio (More nuclei)
- Large nuclei with darker staining chromosome
Cause:
- Rapid multipication of cells
- May demonstrate genetic abnormalities
Tissues commonly affected:
- cervix
- skin
Neoplasia
- Abnormal mass of cells
- Cellular proliferation and growth in the absence of an eternal stimulus
- Variable states of differentiation
- 2 main groups
1) Benign
2) Malignant
Carcinoma in situ
-Features of carcinoma without breach of basement membrane:
- Structural abnormalities
- Cell Crowding
- Pleomorphisms
- increased and abnormal mitotic activity
