Animal Tissue

Animal Tissue

The animal tissues can be divided into the following categories –

1. Epithelial Tissue    2. Connective Tissue

3. Muscular Tissue    4. Nervous Tissue

1. Epithelial Tissue:

Epithelial tissue cover the external surface of the body and internal free surface of many organs. Epithelial cell arranged very close to each other. There are no blood vessels supplying nourishment to epithelial cells. They receive nourishment from under laying connective tissue. The principle functions of epithelial tissues are covering and lining on free surface.

Example: skin, intestine, gland, hollow organ like fallopian tube, nasal passage, bronchioles, trachea etc.

2. Connective Tissue:

These tissue connect and bind different tissues or organs. It provides the structural frame work and mechanical support ot body. It play important role in body as defense tissue, repair, fat storage etc.

Example: Adipose tissue found beneath the skin. Ligament made up of fibrous connective tissue. Cartilage, bone and blood are connective tissue.

• Ligament is fibrous tissue which connect bone to bone.
• Tendon: A flexible, inelastic cord of strong fibrous tissue which attach muscles to bone.

3. Muscular Tissue:

This is also known as contractile tissue. All the muscles of the body are made up of this tissue. Muscle tissue is of three types –
(a) Unstriped, (b) Striped and (c) Cardiac.

(a) Unstriped:

This muscle tissue is found in the walls of those parts which are not controlled by will. These are called involuntary muscle, like – Alimentary canal, Rectum, Ureter, Blood vessels. Unstriped muscles control the motions of all those organs that move on their own.

• Muscular tissues are responsible for the movement in our body.

(b) Striped:

These muscles are found in the parts of the body that move voluntary. Normally one or both the end of these muscles connect with bones by tendon.

(c) Cardiac:

These muscles are found only in the wall of the heart. The contraction and expansion of the heart is due to these muscles that move throughout the life without fail.

• There are over 650 skeletal muscles in the human body.
• The largest muscle of the human body is Gluteus Maximus (muscle of the hip).
• The smallest muscle of the human body is Stapedius.
• On the basis of weight strongest muscles is found in jaw.
• Muscles contain special protein called contractile protein which help in muscle movement.

Note:

• In vertebrates inside the cell and tissues there is a low concentration of K⁺ ion and high concentration of Na⁺ ion.
• Ureters, Iris of eye & Brenchi of lung are made up of smooth muscles.
• Unstriped muscles are also known as smooth muscles.
• Arrector pili are the muscle found in skin which make hair on the skin stand up straight when we are cold or frightened.
• Ciliated epithelium line the inner surface of fallopian tubes, bronchioles and bronchi.

4. Nervous Tissue:

This tissue is also called sensory tissue. The nervous system of the organisms is made up of these tissues. This is made up of two specific cells –

(a) Nerve cell or Neurons and (b) Neurogilia.

Nervous tissue control all the voluntary and involuntary activities of the body.