SKELETAL SYSTEM bones ligaments tendons Development of Bone
SKELETAL SYSTEM bones, ligaments, & tendons
Development of Bone
• Joints -where bones meet!
• IMMOVABLE joints sutures in skull
• SLIGHTLY MOVABLE discs of vertebra
MOVABLE • Ball-and-socket – shoulder, hip • Hinge – elbow, knee • Pivot- first two vertebra • Saddle - base of thumb • Gliding - carpals • Ellipsoid - base of fingers
MUSCULAR SYSTEM Muscles can only contract. They pull on bones to make them move
muscle types o STRIATED ~ skeletal, voluntary o SMOOTH ~ lines most internal organs, involuntary o CARDIAC ~ found only in heart, involuntary
Muscle parts o TENDONS attach the muscle to the bone
MUSCLE CONTRACTION
“SLIDING FILAMENT THEORY” • Thin filaments (ACTIN) and thick filaments (MYOSIN) move past each other by means of CROSSBRIDGES (part of myosin), thus shortening the myofibrils and so shortening (i. e. contracting) the muscle
• ATP is required for muscle contraction and is obtained by either AEROBIC or ANAEROBIC RESPIRATION
Nifty tidbits on the functioning of muscle • “All or none response” means that a single muscle fiber either contracts all the way or not at all • Therefore the strength of a contraction depends on how many fibers fire at once
• ATROPHY = disuse of limb replaces muscle with fat and fibers • HYPERTROPHY = contraction to 75% max (and over time) causes new myofibrils to be formed and, hence, more muscle mass
• SLOW-TWITCH FIBERS with steady tug and more endurance (look light w/i the muscle) • FAST-TWITCH FIBERS more anaerobic and seem to be for strength and explosive bursts of energy. They fatigue quickly (look dark w/i the muscle. )
Slow Twitch is for endurance marathon Fast twitch is for speed and strength
Exercises to help train fast-twitch fibers.
- Slides: 27