What are the 3 layers of the integumentary system?
- the epidermis
- the dermis
- the hypodermis
Define EPITHELIAL TISSUE
Epithelial tissue is tissue composed of cells that line the cavities and surfaces of structures throughout the body. It is one of the simplest animal tissues.
What are the functions of epithelial tissue?
- to protect from dehydration
- to provide sensory surfaces
- to provide the first barrier to infection
- to secrete materials
What are the 7 types of connective tissue?
Bone, blood, skin, tendons, ligaments, cartilage and fascia
Define the EXTRA-CELLULAR MATRIX
The extra-cellular matrix is the non-cellular component in all tissues and organs. It consists of fibres (elastic and collagen) and ground substance. All three provide viscosity and plasticity.
What are the cellular components of tissue?
Fibroblasts, collagen fibres, elastic fibres, ground substance
Fibroblasts create the extracellular matrix and create the structural framework for animal tissue.
Describe collagen fibres
Collagen fibres are produced by fibroblasts. They aggregate into bundles.
Describe elastic fibres
Elastic fibres do not form bundles and have a huge ability to stretch.
In what ways is connective tissue classified?
As loose irregular, dense regular and dense irregular
Describe loose irregular tissue
It is the most common type of connective tissue which holds organs in place and attaches epithelial tissue o other underlying tissues.
Example: areolar tissue
Describe dense regular tissue
It is made of collagen fibres that are bundled together in a parallel fashion. It forms tendons/ligaments but has very poor bloody supply which is why they take so long to heal.
Describe dense irregular tissue
It is not arranged in a parallel fashion. It is mostly found in the dermis and is strong due to the amount of collagen it contains.
Collagen is the most abundant protein in mammals and the most common protein of connective tissue. It supports and holds things in position and consists of matrix or ground substances.
Fascia is the dense fibrous connective tissue that interpenetrates and surrounds the muscles, bones, nerves and blood vessels of the body.
Describe ground substance
A colourless, transparent and homogenous substance. It is primarily made up of glycosaminoglycans.
What are the functions of skin?
- sensory surface