4. Basic Tissues Flashcards
What are the 4 Basic Tissues
- Epithelia
- Connective Tissue
- Muscle
- Nervous
Epithelium location
- Cover surfaces
- Line cavities and tubes
- Form glands
Function of epithelial tissue
- Provide physical protection.
- Control permeability
- Provide sensation
- Produce specialised secretions
Important characteristics of Epihelium
- Attachment - held onto basement membrane
- Avascularity - no blood vessels with the cells
- Regeneration - lost cells are quickly replaced by mitosis
- Polarity (apical and basal)
- Cellularity - cells separated by minimal amounts of ECM
6 main types of epithelium
- Simple squamous
- Keratinised stratified squamous
- Non keratinised stratified squamous
- Simple cuboidal
- Simple columnar
- Pseudostratified stratified columnar with goblet cells
Describe Simple Squamous Epithelium
- Flat cells - oval shaped nuclei
- One layer of cells
Major function - exchange of nutrients and gases
Location – blood vessels, alveoli
Describe Simple Cuboidal Epithelium
- Square cells with round nuclei
- One layer
Major function – secretion and absorption
Location – glands, kidney tubules
Describe Simple Columnar Epithelium
- Tall cells with oval, basally located nuclei
- One layer
Major function – absorption and secretion
Location – gastrointestinal tract
Surface modifications - microvilli
Describe Keratinised Stratified Squamous Epithelium
- Flat surface cells with oval shaped nuclei
- Many layers
- Keratin
Major function – protection, barrier (waterproof)
Location – skin, gums
Describe Non-Keratinised Stratified Squamous Epithelium
- Flat surface cells with oval shaped nuclei
- Many layers
Major function – protection, barrier
Location – oral cavity, oesophagus
Describe Pseudostratified Ciliated Columnar Epithelium with Goblet Cells
- Tall cells
- Appears stratified as some cells don’t reach free surface.
- All cells touch basement membrane
Modifications – cilia & goblet cells
Functions – mucociliary escalator
Location - trachea and large respiratory airways
What is an Intracellular junction?
Specialised area of cell membrane that bind one cell to another.
Describe the 4 Intracellular Junctions. What are their functions?
Tight Junctions
- Interlocking proteins tightly bind cells together near apical edge - Prevent passage of water and solutes between cells – (e.g. in digestive tract)
Desmosomes
- Very strong connections between adjacent cells - Proteoglycan arranged on the side of epithelial cells to bind them together - Resist stretching and twisting
Gap Junctions
- Cells held together by an interlocking membrane proteins containing a central pore - Connexons - Proteins that link two epithelial cells in a gap junction - Allows movement of small molecules and ions between cells - found in cardiac muscle
Hemidesmosomes
- Attach cells to the basement membrane - Stabilise the position and anchor cell to the underlying tissue
Define Connective Tissue
Consists of cells suspended within a uniform extracellular matrix.
Fills internal spaces, provides structural support for other tissues, transports materials within the body, and stores energy
Functions of Connective Tissue
- Forms a structural framework for the body
- Supports, surrounds and interconnects other tissue types
- Protects delicate organs
- Transports fluids and dissolved materials
- Stores energy reserves
- Defends body from microorganisms
