I. FUNCTIONS
A. Primary:
1. Movement - muscles pull on levers.
2. Support:
a. Maintain position or posture.
b. Constriction of viscera, blood vessels, respiratory
passages, etc.
c. Sphincters - regulation of passageways.
B. Secondary:
1. {Heat production. eg. extrinsic eye muscles of some fishes
provide heat for brain.
2. {Electricity production: several kinds have evolved
independently & converged.
May also be of glandular or nervous origin.
Communication, orientation, prey location, offense, or
defense.Up to >500V}
II. ORGANIZATION OF MUSCLES
A. Muscle types:
1. Red vs. White.
2. Skeletal vs. Visceral.
3. Voluntary vs. Involuntary.
4. Morphology: (see supplementary handout)
a. Skeletal (striated).
b. Cardiac.
c. Smooth.
B. Muscle attachments:
1. Tendons - attach muscles to bones; inelastic; continuous w/
surface of bone;
low maintenance (little vasculature required).
a. Transmit force from muscle to bone.
b. May attach at distance from muscle.
c. Allows for small attachment area.
d. Concentrates force.
e. Allows for precision of movement.
f. Affects weight (mass) distribution, agility.
2. Aponeurosis = tendon drawn into broad, thin sheet of
connective tissue.
3. Fascia = aponeuroses that wrap/bind parts of body together.
III. MECHANICS OF CONTRACTION
A. Tension vs. length.
B. Fiber orientation:
1. Parallel:
a. Longer effective distance.
b. Force proportional to cross-sectional area.
c. Faster.
2. Pinnate (oblique):
a. More fibers in the same volume.
b. Suited for moving heavy loads short distances.
c. Slower.
C. Length vs. speed.
D. Muscle actions:
1. Flexor vs. extensor.
2. Adductor vs. abductor.
3. Elevator (levator) vs. depressor.
4. Constrictor vs. dilator.
5. Protracter vs. retractor.
6. Rotator:
a. Supinator --> turn palm up.
b. Pronator --> turn palm down.
7. Tensor.
