Great ape - opposable thumb and big toe. Our opposable thumb allows grasping. Has blood vessel, nerve. Bone deposited around osteoblast until trapped in lacunae spaces, then cells called osteocytes. Bones remodeled throughout life.
All cells have actin and myosin, contractile proteins.
Calcium ions bind to troponin molecule, shape change that moves tropomyosin away from actin active site. Generates a little ATP, also lactic acid. Weaker contractions, muscle fatigue from lack of ATP Conditioning trains muscles to handle high lactic acid concentrations Panting after exercise repays oxygen debt as lactic acid converted back to glucose, ATP and CP reserves rebuilt. Antagonist - produces movement opposite the agonist. Antagonist is relaxed when agonist contracts.