3 Muscle structure and composition

D C Saxena and Kulsum Jan

epgp books
Contents:

 

1. Muscle Mass

 

2. Classification of Muscles

 

2.1 Presence/Absence of striations

 

2.1.1 Striated muscle

 

2.1.2 Non-striated muscle

 

2.2 Depending on the control

 

2.2.1Voluntary Muscle

 

2.2.2Involuntary muscle

 

2.3  Depending on the type Function

 

2.3.1 Skeltal Muscle

 

2.3.2 Cardiac muscle

 

2.3.3 Smooth Muscle

 

3. Muscle structure

 

Introduction:

 

Muscle Mass:

 

1. The muscle mass or muscle tissue is made up of large number of single muscle cell.

 

2. The muscle cells are commonly called Muscle fibers because these cells are long and slender in appearance.

 

3. Each muscle fiber is cylindrical in shape with average length of 3 cm- 4 cm varies upon the length of muscle.

 

4. The tendon of some muscle is flat and thin but tough. Each muscle fiber is enclosed by a cell membrane called sarcollema. The cytoplasm of muscle is called sarcoplasm. Nuclei, myofibril, golgi apparatus, mitochondria and ribosomes etc are embeded in sarcoplasm

 

Classification of Muscles

 

Muscles in the body perform different functions, having different shape and different mode of actions. Therefore muscles are classified under 3 types

  • Presence/absence of striations.
  • Control
  • Function

 

Presence/Absence of striations:

 

On the basis of presence of cross striation, muscles are divided into two groups:

  • Striated muscle
  • Nonstirated muscle

 

Depending on the control

 

Depending on the control muscle are of following 2 types:

  • Voluntary Muscle:
  • Involuntary Muscle:

 

Depending on the type Function

 

These muscle are classified into 3 types:

  • Skeltal Muscle
  • Cardiac Muscle
  • Smooth Muscle

 

Muscle structure and Biomechanism of contraction:

  • Muscle fibres are grouped into bundles (of up to 150 fibres) called fasciculi. Each fasiculus or bundle is surrounded by connective tissue called perimysium.
  • Each individual fibre consists of a membrane (sarcolemma) and can be further broken down into hundreds or even thousands of myofibrils.
  • Myofibrils are surrounded by sarcoplasm and together they make up the contractile.
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References

  1. Bear, Richard S., “The structure of collagen Fibrils,” Advances in protein chemistry., 7,69-161 (1952).
  2. Huggins, M.L., “The structure of Collagen,” Proc. Natl. Acad. Sci., 43,209 (1957).
  3. Urbain, W.M., “ Meat and meat products’” in Jacobs, M.B., ed., “ Chemistry and technology of food and food products,’ Interscience publication., Inc., New York, N.Y., 1951.
  4. Whitaker, J.R., “Chemical Changes associated with ageing of meat with emphasis on the protein,’ Advances in Food research, 9 (1959).