muscular tissuemuscular tissue in general

Question

MUSCULAR TISSUE

Muscular tissue in general develops from the mesoderm of the embryo but the muscles of the iris of the eye and myoepithelial cells of the salivary, mammary and sweat glands arise from the ectoderm of the embryo.

 

GENERAL STRUCTURE -

1. This tissue constitutes the muscles, made up of cells, which are in the form of contractile fibres varying in lengths.
2. The fibres are bound together by connective tissues but they have no intercellular substance.
3. Myoblasts give rise to muscle fibres. Myocytes (= sarcocytes) are muscle cells.
4. Each fibre consists of fine fibrils called myofibrils, present in the cytoplasm known as sarcoplasm.
5. Sometimes the muscle fibre is externally covered by a membrane, termed as sarcolemma.
6. The special property of muscular tissue is contractility & excitability.
7. It is due to the energy stored in the electrical potential difference across the plasma membrane.

 

FUNCTIONS OF MUSCULAR TISSUE -

1.      It brings about movements of the body parts and locomotion of the individual.

2.      Muscles are responsible for peristalsis in tubular viscera, heart beat, production of sound, etc.

3.      Facial expression also depends on muscles.

4.      It supports the bones and other structures.

5.      Muscles are required for delivering a baby.