Histology of Epithelial Tissues

Study Notes

Stratified Cuboidal Epithelium: Found in salivary glands, sweat glands, and mammary glands.
Stratified Columnar Epithelium: Primarily located in the male urethra.
Pseudostratified Epithelium: Appears multilayered but consists of a single layer of columnar cells. Contains goblet cells that release mucus.

Endocrine Glands: Ductless glands that secrete hormones directly into the bloodstream.
Exocrine Glands: Secrete substances onto body surfaces through ducts; can be categorized by structure:
- Merocrine: Most common, releases serous and mucus secretions.
- Apocrine: Accumulates secretion on apical side; e.g., sweat glands in the axilla.
- Holocrine: Results in cell rupture, destroying glandular cells.
Transitional Epithelium: Located in the bladder, allows for stretching and recoiling.

Functions: Provides support, binds tissues, protects organs, stores energy, and transports substances (e.g., blood).
Components:
- Cells: Includes fibroblasts, macrophages, and adipocytes.
- Extracellular Matrix (ECM): Composed of ground substance and fibers (collagen, elastic, reticular).

Loose Connective Tissue: Absorbs shocks, binds tissues, allows diffusion of nutrients.
- Areolar: Provides support with a loose web appearance.
- Adipose: Stores fat, acts as insulation and protection. Contains white (yellow fat) and brown (heat-generating) types.
- Reticular: Creates a framework for lymphatic organs.
Dense Connective Tissue: More collagen fibers.
- Dense Regular: Parallel fibers found in tendons and ligaments.
- Dense Irregular: Fibers arranged in multiple directions, found in the dermis.
- Elastic: Allows stretching, found in arteries.
Specialized Connective Tissue:
- Cartilage: Avascular, provides flexible support with some cushioning.
- Bone: Rigid structure, provides support and protection.

Smooth Muscle: Involuntary control, non-striated, located in walls of hollow organs (e.g., intestines, blood vessels).
Nervous Tissue: Composed of neurons and neuroglia.
- Functions: Communication through electrochemical impulses, coordination, and control.
- Neuron Structure:
  - Dendrites: Receive signals towards the cell body.
  - Axon: Transmits impulses away from the cell body.
  - Cell Body (Soma): Contains nucleus and organelles.

Nutritional Status:
- Protein is crucial for collagen synthesis.
- Vitamins A and C support epithelial proliferation and collagen synthesis, respectively.
- Zinc aids in DNA synthesis.
Blood Supply: Crucial for delivering oxygen and nutrients to healing tissues; angiogenesis is essential for continued support.
Infection: Delays healing; proper wound care and antibiotics are necessary.
Age: Younger individuals heal more efficiently than older adults.
Chronic Conditions: Conditions like diabetes can impair wound healing.

Keloids: Overgrowth of scar tissue; treatment options include steroid injections and surgery but may recur.
Contractures: Permanent tightening due to burns; can restrict movement and may require physical therapy or surgery.
Chronic Wounds: Fail to heal normally, often staying in the inflammatory phase; managed with advanced techniques like negative pressure therapy.
Tissue Engineering: Explores methods like stem cells and bioengineered tissues for enhanced repair with minimal scarring.

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