Chapter 9: Muscular System
Skeletal
Cardiac
Smooth
Functions of skeletal muscle: movement, posture, support, entrance and exit control, body temperature
Epimysium: layer of connective tissue surrounding the muscle
Perimysium: connective tissue that divides muscle into fascicles
Endomysium: surrounds each skeletal muscle fiber. Muscle fiber = muscle cell.
Tendons: attach muscle to bone
Aponeuroses: similar to tendons, attach muscles to part they move but tend to cover muscle
Sarcolemma: muscle cell membrane
Sarcoplasm: muscle cell cytoplasm
Satellite cells: undifferentiated myoblasts
Myofibrils: contractile filaments running entire length of the cell
Sarcoplasmic reticulum: analagous to endoplasmic reticulum, intimately involved with Ca++ levels
Muscle Contraction: Electrical impulse from motor neuron causes release of Acetyl Choline (ACh) at the neuromuscular junction which binds to receptors on the sarcolemma surface which results in release of Ca 2+ which initiates muscle contraction. ACh is broken down by acetylecholinesterase (AChE) which results in the reverse of above and the end of contraction.
Curare: drug causing muscle paralysis used by natives in South America and now by us.
Muscle tone: resting tension of muscle
Hypertrophy: a generic term but in muscle it is an increase in the number of myofibrils
Atrophy: generic term but in muscle it means the fibers become smaller
Types of skeletal muscle:
Fast fibers
Slow fibers
Organization of skeletal muscle: and another
Origin: stationary or proximal attachment
Insertion: moveable or distal attachment
