Homeostasis
- Definition:
- ✅ The body's ability to maintain a dynamic steady state of internal balance or equilibrium.
Cell Changes
1. Hyperplasia
- ✅ Definition: Increased number of cells.
2. Hypertrophy
- ✅ Definition: Increased size of cells.
- Causes: Increased workload or pathological conditions.
3. Atrophy
- ✅ Definition: Reduced size of cells.
- Causes: Disuse, malnutrition, and decreased blood flow.
4. Metaplasia
- ✅ Definition: Replacement of one cell type with another that can better endure stress.
- Causes: Chronic inflammation or irritation.
5. Dysplasia
- ✅ Definition: Abnormal cell growth of a specific tissue.
- Preceding Condition: Indicates potential cancerous changes.
Cellular Changes Related to Sodium and Calcium
- Sodium Build-up:
, - ✅ Occurs due to the breakdown of the sodium-potassium pump.
- Consequence: Sodium collects in the cell, attracting water and causing intracellular swelling.
- Fatty Changes:
- ✅ Lipid accumulation in cells leads to impaired cell functions, often resulting in conditions like "fatty
liver."
- Calcium Build-up:
- ✅ Calcium accumulates due to the breakdown of the Ca²⁺/Mg²⁺ pump.
- Consequence: Inappropriate activation of cellular enzymes.
Cell Death Mechanisms
1. Apoptosis
- ✅ Controlled cell death (implosion) where all components remain within the cell, eliciting no
inflammatory response.
2. Necrosis
- ✅ Uncontrolled cell death (explosion) where cell contents are released into the extracellular space,
triggering an inflammatory response.
Organs of the Immune System
- Bone Marrow: Produces RBCs, WBCs, and platelets.
- Thymus Gland: Site of T-cell production.
- Lymph Nodes
- Tonsils
- Spleen
Telomeres
- ✅ Outermost tails of the chromosome arms.