Tissues Flashcards
What are the four types of tissue?
- Epithelium
- Connective
- Muscle
- Nerve
What are the main functions of epithelial tissue?
- Covers surfaces
- Separates compartments
- Forms glands- specialised secretory organs
What is endothelium?
Internal epithelium
What re the secondary roles of epithelial tissue?
- If thick, to protect against wear and tear. If thin, to allow for diffusion.
- Allow movement via cilia
- Allow absorption via microvilli.
What are the three types of epithelial cell?
- Squamous
- Columnar
- Cuboidal
What is the difference between simple and stratified epithelial tissue?
Simple epithelial tissue consists of one layer of cells.
Stratified epithelial tissue consists of multiple layers of cells.
NB: Can be pseudostratified
What are the three types of cell to cell junctions?
1) Desmosomes
2) Tight junctions
3) Gap junctions
What is the characteristics of desmosomes?
- Firm anchorage between cells
- Not watertight
What are the characteristics of tight junctions?
- Seal intracellular spaces
- Watertight
What are the characteristics of gap junctions?
- Link cytoplasm of different cells
- Allow cell to cell communication
What is a hemidesmosome?
A cell- ECM junction connecting a cell to the basement lamina.
What is the difference between an exocrine and an endocrine gland?
Exocrine glands secrete substances onto the surface of a structure.
Endocrine glands secrete substances into a vessel.
What is the difference between a tubular and an acinar gland?
Tubular glands are long, thin, straight invaginations which release a watery secretion
Acinar are grape like invaginations which release a mucous secretion
What is a myoepithelial gland?
Specialised epithelial cells which act as muscle, contracting to squeeze out secretion.
What type of tissue are cartilage, bone and adipose examples of?
Connective tissue
Describe the structure of an adipose cell.
Nucleus surround by thin layer of cytoplasm and larger layer of lipid.
What is the extracellular matrix made up of?
Fibres (collagen, elastic)
Ground substances
Tissue Fluid
What is meant by the term compound gland?
Contains both tubular and acinar glands
How do exocrine glands form?
Epithelial layer invaginates, creating a tube.
How do endocrine glands form?
Cells proliferate to form a mass of secretory cells which loose contact with the epithelial surface and accumulate around a blood vessel.
What are glands?
Collections of secretory epithelial cells
