VPB 121: Veterinary Physiology - II (2+1)

TYPES OF MUSCLES

• In mammal three kinds of muscles tissue are found
  • Skeletal muscles
    • Cross striated and attached to skeleton
    • 40% of the total body weight
    • Voluntary neural control.
  • Cardiac muscle
    • Cross striated
    • Involuntary in function
    • Under autonomic nervous system control.  
  • Myofibrils are similar to skeletal muscle except at the point of "Z" line cardiac muscle forms Intercalated Disc which forms the muscular network of "Syncytium".
  • T tubular system is present at the level of Z line and not at the level of A and I bands.
  • Triads are simple due to ill developed sarco plasmic reticulum.
  • cardiac muscles have rich mitochondrial supply and many Ca-Na exchangers.
  • Smooth muscle
    • No cross striations found, poorly organized Actin and Myosin filaments.Ratio of Actin and Myosin is 15:1
    • Absence of Troponin complex.
    • Involuntary under ANS control
    • 10% of the total body weight
    • Found in the walls of blood vessels, lymph vessels, urinary tract, digestive, respiratory, reproductive organs and gizzard of chickens and turkey.
    • Exist as Multi unit and single unit muscle fibres.
    • Muscles cells, like neurons can be excited chemically, electrically and mechanically to produce an action potential that is transmitted along their cell membrane Sarcolemma. They contain contractile proteins which are activated by action potential.