what is principally in charge of our movements?
muscle tissue, muscle tissue is also responsible for all of our voluntary behavior and a good share of our involuntary behavior
what percentage of our body weight is muscle?
what are the three types of muscle tissue?
striated, smooth and cardiac
- innervated by the peripheral nervous system, voluntary muscle because it is primarily attached to the skeletal structure
- -fatigues easily
- -even at rest there is some tension (muscle tone)
- -group of muscle fibers=fasciculi
- autonomic nervous system (aka visceral muscle because of location)
- -stomach, intestines, blood vessels, bronchial tubes
- ONLY IN THE HEART
- -involuntary-but striated
- -heart begins to contract in the very early days of embryonic life
- -72 beats per min normal>100,000/day
- -26,000,000,000 times in 70 years
- -pumps 40,951,000 gallons of blood
- -DOES NOT FATIGUE
what are the two points of attachment for muscles?
- origin-fixed point (proximal, closer to center)
- insertion-structure being acted upon (distal, away from center)
NOT ALWAYS THE CASE THOUGH
think in terms of thyrohyoid
(reach and pull object down) and hyothyroid
(reach and pull yourself up to the object)
what produces movement?
muscle contractions, especially for the extremities but less true of postural muscles
how do skeletal muscles generally produce movement?
by acting on a joint that lies between the origin and insertion of the muscle
contraction of muscle tissue __________ the distance between the _____ and ______.