Describe epithelial tissue
- It covers surfaces and separates compartments
- Forms glands
- Cells are connected and define function
- Has a diversity of secondary functions
Describe connective tissue
- It connects
- Structure and function defined by fluid and extracellular matrix
- Liquid to solid matrix
- Includes blood, bone and adipose
Describe muscle tissue
- Long thin cells which have cytoplasm packed with contractile apparatus
- Contractile
- Shortens in length and closes down spaces
What kind of muscle tissues are there?
- Skeletal
- Smooth
- Cardiac
Describe nervous tissue
- Important in communication
- Consists of neurones and support cells
- Receives, generates and transmits electrical signals
- Integrates information from around the body
How does epithelial tissue maintain coverage of surfaces?
- No contact inhibiton
- Cell-cell junction
- Cell-ECM junctions
What is a desmosome?
A cell-cell junction
What is the purpose of a desmosome?
Firm anchorage
What is the structure of a desmosome?
Two cells stick together by a plaque of protein and filamentous proteins radiate out
What is a tight junctions?
A cell-cell junction
What is the function of a tight junction?
Seals intracellular spaces
What is a gap junction?
A cell-cell junction
What is the function of a gap junction?
Cell to cell junction
How do gap junction allow for communication?
- Signals go between the cells
- Holes are punched in the membrane which allow for the movement of ions
What is the basement membrane composed of?
- Reticular lamina
- Basal lamina
What sits in the basement membrane?
Four nucleated cells
What cell-ECM junction exists?
- Hemidesmosomes
- Skin basal lamina
- BV endothelium-BL
What are the secondary roles of the epithelium?
- Thick for wear and tear
- Thin for diffusion
- Movement - cilia
- Absorption - microvilli
What is cilia?
Finger like projections from the apical surface
What are microvilli?
Finger like projections from the apical surfaces
How can epithelia be classified?
- Either simple (one cell thick) or complex (more than 1 cell thick)
- Squamous (squashed)
- Cuboidal
- Columnar
- Stratified (spherical cells)
- Pseudostratified columnar (appears like more than one layer but every cell has contact with the basal lamina
What are cuboidal and columnar cells used for?
Secretion
Where are stratified epithelia found?
Bladder and UT to stop accumulated toxins leaking back into the system
Where are pseudostratified columnar epithelium found?
Trachea
