chapter 9 vocab
fascia
layers of CT that separate muscles from one another and hold the muscle in place
tendon
cordlike, connects muscle to bone
aponeuroses
broad fibrous sheets; attach to bone or adjacent muscle
myofibrils
thin and thick actin/ myosin filaments
myosin
2 twisted protein strovids with globular ends called cross bridges
- thick filaments
- forms filaments that interact to contract muscle fibers
actin
thin filaments; actin protein: double strands of actin twisted into helix
-forms thin filaments that slide between filaments of the protein myosin, shortening muscle fibers
sacromeres
repeating pattern of units
neuromuscular junction
a synapse where neuron axon and skeletal muscle fiber interact
acetylcholine (ACh)
neurotransmitters used by muscles
sliding filament model
sarcomeres shorten and thick and thin filaments slide past one another
- z lines closer, H and L narrow
ATPase
enzyme that transfers the energy stored in terminal phosphate bonds of ATP molecules
creatine phosphate
molecule in muscle that stores energy
myoglobin
oxygen -storing pigment in muscle tissue
oxygen debt
amount of oxygen muscle cells require after physical exercise to restore levels of glucose, ATP and creatine
twitch
time between the application of a stimulus and the beginning of a response in a muscle fiber
latent period
brief delay
summation
increase force of contraction by a skeletal muscle fiber when a twitch occurs before previous twitch relaxes
complete tetanic contraction
sustained contraction lacks even partial relaxation
recruitment
increase in number of motor units taking part in a muscle contraction
- multiple motor unit summation
muscle tone
continuous state of partial contration
isotonic contraction
equal force- equal change in length
concentric contraction
shortening contraction
eccentric contraction
lengthening contraction (less muscle force than opposing force)
isometric contraction
tension within muscle increases and muscles remain the same length
(equal length- change in force)
peristalsis
wareike motion in tubular organs
origin
less movable end
insertion
more movable end
prime mover (agonist)
muscle that causes an action
synergists
muscle that assist agonist/ prime mover
antagonists
muscle whose contraction causes movement in the opposite direction of the prime mover