Changes

==Introduction==

==Introduction==

Muscle mass accounts for a large majority of the carcass weight of domestic animals.  Muscular contraction is necessary for voluntary and involuntary movement of limbs, stabilization of joints, maintaining luminal diameter (in the case of arteries, bowel, etc), and to produce heat. The number of muscle fibers an individual possesses is determined by genetics and is set at birth, although muscle size and type (i.e. glycolytic to oxidative and vice versa) can be altered. Further muscle development therefore occurs by hypertrophy, rather than hyperplasia of muscle fibers. Three types of muscle can be described:

Muscle mass accounts for a large majority of the carcass weight of domestic animals.  Muscular contraction is necessary for voluntary and involuntary movement of limbs, stabilization of joints, maintaining luminal diameter (in the case of arteries, bowel, etc), and to produce heat. The number of muscle fibers an individual possesses is determined by genetics and is set at birth, although muscle size and type (i.e. glycolytic to oxidative and vice versa) can be altered. Further muscle development therefore occurs by hypertrophy, rather than hyperplasia of muscle fibers. Three types of muscle can be described:

Cardiac muscle is striated but uninucleate and highly vascularized. There are gap junctions concentrated at intercalated discs.

Cardiac muscle is striated but uninucleate and highly vascularized. There are gap junctions concentrated at intercalated discs.

'''Myogenic Contraction''' spreads cell to cell and does not depend on nervous imput to individual cells. Areas of low electrical resistance allow rapid spread of action potentials. Contraction is regulated by autonomic neurons and circulating hormones. The contractile mechanism is similar to skeletal muscle, an increase in cytosolic Ca. There is a Ca influx across the plasma membrane AND the sarcoplasmic reticulum. The action potential has a prolonged plateau phase.

'''Myogenic Contraction''' spreads cell to cell and does not depend on nervous input to individual cells. Areas of low electrical resistance allow rapid spread of action potentials. Contraction is regulated by autonomic neurons and circulating hormones. The contractile mechanism is similar to skeletal muscle, an increase in cytosolic Ca. There is a Ca influx across the plasma membrane AND the sarcoplasmic reticulum. The action potential has a prolonged plateau phase.

==Tendon==

==Tendon==

}}

}}

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:A&P Done]]

[[Category:A&P Done]]