Different types of tissues

Different types of tissues

● Epithelial Tissue:-

1. The protective covering in the animal body is called epithelial tissue.
2. Cells in this tissue are closely packed without intracellular spaces & hence they form continuous layers.
3. Any material that enters the body first encounters the epithelial tissue & provides protection.
4. Cells of the epithelial tissue are separated from cells of other underlying tissues by a fibrous membrane.
5. The skin, mucous layer, and inner surface of blood vessel walls of alveoli are made up of epithelial tissue.
6. There are various types of epithelial tissue, such as squamous, stratified, glandular, columnar, ciliated & cuboidal epithelium, etc.

● Connective Tissue:- 

1. Tissues that join the different parts of the body are called connective tissue.
2. Cells in this type of tissue are loosely arranged with intracellular spaces filled with ground substances.
3. Ground substances may be solid, liquid, or jelly-like.
4. They are present in the under the epidermis, in the walls of tubular organs, and inside solid organs.
5. It is mesodermal in origin & composed of free cells in a mass of fibers in a fluid or viscous group substance.

6. There are 3 main types of C.T.:-

    (I) Connective tissue proper = Areolar, adipose, reticular, elastic, fibrous.

    (II) Skeletal tissue = cartilage & bone.

    (III) Fluid connective tissue = Blood & lymph

● Muscular Tissue:- 

1. Muscle fibers & muscular tissue are formed from a special type of contractile proteins.
2. The contractile proteins like actin & myosin bring contraction & relaxation of muscles.
3. Muscular tissue is made up of long cells of fibers.
4. Muscular movement occurs due to the contraction & relaxation of contractile proteins in these cells.
5. They are seen attached to the bones and present in the alimentary canal, blood vessels, heart, etc.
6. These are of 2 type-voluntary muscles & Involuntary muscles.
7. Voluntary muscles are striated & skeletal muscles are because they show alternate light & dark bands & seen attached to bones.
8. Involuntary muscles are non-striated because it does not have dark & light bands, & not in our control.

● Nervous Tissue:-

1. It enables us to respond to stimuli like touch, sound, odor, color, etc.
2. Cells of the nervous tissue are specially made to be excited & to conduct that excitation from one part of the body to another.
3. The cell body which contains cytoplasm & nucleus is the main part of each nerve cell.
4. Numerous small branched fibers are called dendrites. Arises from each cell body.
5. One of the fibers is extremely large called an axon.
6. The length of the nerve cell may measure up to one meter.
7. Many nerve cells are bound together with the help of connective tissue to form a nerve.
8. Nervous tissue is present in the brain, spinal cord and network of nerves spread all through the body.