Types of Tissues
4 Types
1. Epithelial Tissue (Epithelium): Covers body surfaces, lines cavities, and forms glands.
2. Connective Tissue: Binds cells and organs, providing support and protection.
3. Muscle Tissue: Excitable and contracts to facilitate movement.
- Types:
a. Skeletal Muscle: Voluntary control.
b. Smooth Muscle: Involuntary control in organs.
c. Cardiac Muscle: Heart muscle, involuntary.
4. Nervous Tissue: Propagates electrochemical signals (nerve impulses) for communication
Tissue Membranes
Thin layers of cells covering body surfaces and organs.
- Types:
1. Connective Tissue: Formed from connective tissue (e.g., synovial membranes in joints).
2. Epithelial Membranes: Composed of epithelium and underlying connective tissue.
3. Mucous Membranes: Line cavities open to exterior (e.g., digestive, respiratory tracts).
4. Serous Membranes: Line closed body cavities; secrete serous fluid for lubrication (e.g.,
pleura, pericardium, peritoneum).
5. Cutaneous Membrane: Skin; stratified squamous epithelium with keratinized cells.
Epithelial Tissue
Features
- Cellularity: Highly cellular with minimal extracellular material.
- Cell Junctions: Special connections between cells (tight, anchoring, and gap junctions).
- Basement Membrane: Made of basal lamina (glycoproteins+collagen) & reticular lamina
- Avascular: No blood vessels; nutrients diffuse from underlying tissues.
Functions
- Protection: First line against physical, chemical, and biological damage.
- Permeability Control: Selective transfer of materials.
- Secretion: Release of mucus and enzymes (e.g., digestive enzymes in the small intestine).
Epithelial Cell Types
- Cilia: Extensions that help move fluids and particles (e.g., in respiratory tract).
- Goblet Cells: Mucus-secreting cells interspersed among epithelial cells.
, Types of Cell Junctions
- Tight Junctions: Prevent passage between cells, creating a barrier.
- Anchoring Junctions: Stabilize tissue; includes desmosomes, hemidesmosomes
- Gap Junctions: Allow communication between adjacent cells.
Classification of Epithelial Tissue
- By Cell Shape:
a. Squamous: Flattened cells.
b. Cuboidal: Box-like cells.
c. Columnar: Taller than wide cells.
- By Layering:
a. Simple Epithelium: Single layer.
b. Stratified Epithelium: Multiple layers.
c. Pseudostratified: Appears stratified but is a single layer.
d. Transitional: Specialized for stretching (e.g., bladder).
Specific Types of Epithelial Tissue
Tissue Looks Function Location
Simple Squamous allows diffusion alveoli, blood vessels
Simple Cuboidal absorbs and secretes kidney tubules, glands
Simple Columnar absorbs and secretes digestive tract
Pseudostratified secretes mucus and respiratory tract
Columnar moves particles
4 Types
1. Epithelial Tissue (Epithelium): Covers body surfaces, lines cavities, and forms glands.
2. Connective Tissue: Binds cells and organs, providing support and protection.
3. Muscle Tissue: Excitable and contracts to facilitate movement.
- Types:
a. Skeletal Muscle: Voluntary control.
b. Smooth Muscle: Involuntary control in organs.
c. Cardiac Muscle: Heart muscle, involuntary.
4. Nervous Tissue: Propagates electrochemical signals (nerve impulses) for communication
Tissue Membranes
Thin layers of cells covering body surfaces and organs.
- Types:
1. Connective Tissue: Formed from connective tissue (e.g., synovial membranes in joints).
2. Epithelial Membranes: Composed of epithelium and underlying connective tissue.
3. Mucous Membranes: Line cavities open to exterior (e.g., digestive, respiratory tracts).
4. Serous Membranes: Line closed body cavities; secrete serous fluid for lubrication (e.g.,
pleura, pericardium, peritoneum).
5. Cutaneous Membrane: Skin; stratified squamous epithelium with keratinized cells.
Epithelial Tissue
Features
- Cellularity: Highly cellular with minimal extracellular material.
- Cell Junctions: Special connections between cells (tight, anchoring, and gap junctions).
- Basement Membrane: Made of basal lamina (glycoproteins+collagen) & reticular lamina
- Avascular: No blood vessels; nutrients diffuse from underlying tissues.
Functions
- Protection: First line against physical, chemical, and biological damage.
- Permeability Control: Selective transfer of materials.
- Secretion: Release of mucus and enzymes (e.g., digestive enzymes in the small intestine).
Epithelial Cell Types
- Cilia: Extensions that help move fluids and particles (e.g., in respiratory tract).
- Goblet Cells: Mucus-secreting cells interspersed among epithelial cells.
, Types of Cell Junctions
- Tight Junctions: Prevent passage between cells, creating a barrier.
- Anchoring Junctions: Stabilize tissue; includes desmosomes, hemidesmosomes
- Gap Junctions: Allow communication between adjacent cells.
Classification of Epithelial Tissue
- By Cell Shape:
a. Squamous: Flattened cells.
b. Cuboidal: Box-like cells.
c. Columnar: Taller than wide cells.
- By Layering:
a. Simple Epithelium: Single layer.
b. Stratified Epithelium: Multiple layers.
c. Pseudostratified: Appears stratified but is a single layer.
d. Transitional: Specialized for stretching (e.g., bladder).
Specific Types of Epithelial Tissue
Tissue Looks Function Location
Simple Squamous allows diffusion alveoli, blood vessels
Simple Cuboidal absorbs and secretes kidney tubules, glands
Simple Columnar absorbs and secretes digestive tract
Pseudostratified secretes mucus and respiratory tract
Columnar moves particles
