Types of biological tissues Flashcards
What are the four types of biological tissues?
Epithelial
Connective
Muscle
Nervous
What are the two types of epithelial tissue?
Proper and glandular epithelium
Briefly describe proper epithelium
It covers and lines the inner and outer body
Briefly describe glandular epithelium
It forms glands and secretes hormones, as well as other substances
Where is epithelial tissue found?
- Interface between compartments
- Line / cover all body surfaces, cavities and tubes
- Glands
Name three functions of epithelium
- Covering, lining and protecting surfaces
- Performing absorption
- Secretion
What are the characteristics of epithelia?
–Specialised cell to cell junctions
–Polarised
–Basement membrane
–Avascular– rely on connective tissue
What are the three types of epithelium cell types?
Squamous
Cuboidal
Columnar
Squamous epithelium
Lining and diffusion •Endothelium •Blood vessels and lymph •Mesothelium •Body cavities linings
Columnar epithelium
Much more active
What are the three types of layers of epithelium?
Simple- one layer of cells
Stratified- multiple layers on top of each other
Pseudostratified- mostly just one layer. Cells with different shapes and sizes
What is transitional epithelium?
Stratified epithelium that can accommodate stretching
Type of epithelium required for selective diffusion?
These epithelia are usually simple squamous type, to provide the smallest barrier to diffusion.
Type of epithelium required for absorption/secretion?
These epithelia are usually columnar, as the cells contain lots of ER and golgi, for secretion. They often have microvilli, to increase the surface area of the apical surface for absorption.
Type of epithelium required for physical protection?
These epithelia are always stratified (many layers), and can sometimes be keratinised on its apical surface, as in skin. The keratin helps to waterproof the skin.
Where do endocrine glands secrete into?
They secrete hormones into the blood or to nearby cells
Where do exocrine glands secrete into?
They secrete into tubes/ducts that lead to the outside of the body
What can secretory cells synthesise, store and release?
- Proteins-e.g. in the pancreas
- Lipids-e.g. adrenal, sebaceous glands
- Complex of carbohydrates and proteins-e.g. salivary glands
- All the above-e.g. lactating mammary glands
Name the four types of connective tissue
Proper
Cartilage
Bone
Blood