Muscles Flashcards
traits of striated muscle (skeletal muscle)
somatic, most power, fastest, most organized
traits of smooth muscle
autonomic, slowest, least power
traits of cardiac muscle
autonomic, less fast, slower
organization of skeletal muscle
connective tissue (epimysium and perimysium) wrap muscle bundles, blood vessels, and nerves; muscle bundles wrapped in connective tissue with muscle fibers inside; myofibril inside muscle cells
thick filament
myosin
thin filament
actin
actin
made of actin and tropomyosin –> tropomyosin blocks actin binding sites
myosin
2 polysaccharides wound into a helix and create a filament, have a globular head
how many actin are surrounding myosin?
6
sarcomere
smallest unit of contraction in muscle
troponin
bound to tropomyosin keeping it in place, affected by calcium
Z disc
defines the lateral border of the sarcomere
A band
myosin and actin overlap, dark, length remains unchanged during contraction
I band
only actin, light, cross in the middle (Z disc), length contracts or shortens during contraction
sliding filament model
myosin pulls actin towards the center
cross bridge cycle
- myosin head binds to ATP leading to detachment from actin, 2. myosin head catalyzes the hydrolysis of ATP and cocks the myosin head back, 3. myosin head binds to actin forming a cross bridge, 4. ADP is released and produces a power stroke that causes shortening of the sarcomere
motor endplate
where neuron synapses with muscle
T tubule
connects the sarcoplasmic reticulum and the depolarization is sent through it
sarcoplasmic reticulum
storage site for calcium ions and releases them when action potential is sent
antagonistic muscles
extension, bringing bones further apart
agonist muscles
bringing bones together, flexion
twitch contraction
one contraction, not usually summed
tetanic contraction
many summed contractions at once causing complete contraction of the muscle
motor unit
control very large muscle groups and allow for big forces
