Module 5.3 - Physiology of the Muscular System Flashcards
Which type of muscles are under involuntary control?
smooth and cardiac muscle
Voluntary muscle control
conscious decision made to move muscle
Which types of muscles have striations?
cardiac and skeletal muscles
What is the one motion muscles can make?
pulling by contracting
flexion
closing of a close
extension
opening of a joint
antagonistic muscle pair
perform opposing muscle actions (e.i flexon/extension)
abduction
movement away from midline
adduction
movement toward midline
dorsiflexion
flexion superiorly occurring at the subtalar (ankle) joint (movement of the toes “up”)
plantarflexion
flexion inferiorly occurring at the subtalar (ankle) joint (movement of the toes “down”)
radial deviation
lateral movement of wrist toward radius
ulnar deviation
medial movement of wrist toward ulna
pronation
rotation of forearm so palm faces posteriorly or rotation of ankle so sole of foot facing laterally
supination
rotation of forearm so palm faces anteriorly, or rotation of ankle so sole of foot faces medially
elevation
upward movement of structure
depression
downward movement of structure
retraction
movement of structure to be drawn in posterior direction (backward)
proctraction
movement of structure to be drawn in anterior direction (forward)
muscle fiber
cell containing thousands of myofibrils
myofibrils
contractile portions of the fibers, cylindrical in shape, run length of muscle fiber
striations
the light and dark bands of myofibrils formed by sacromeres
sarcomere
contractile unit formed from by protein myofilaments
What are the 2 types od protein myofilaments?
myosin and actin
Myosin
thick filaments of proteins in sarcomeres
Actin
thin filaments of protein in sarcomere
How do sarcomere shorten?
actin filaments slide along myosin towards each other
How is 1 sarcomere viewed/ measured under microscope?
Z-line to Z- line
Z lines
connect the parallel bands of thin filaments
M lines
hold together parallel thick filaments
I band
appears light when stained because it contains only thin filaments
A band
stains darker under microscope because it has both thin and thick filaments
What do the lines of sarcomere do when muscles contract?
Z lines move closer together toward the M line
What happens at neuromuscular junction?
a nerve impulse reaches the muscle fiber and acetylcholine is released from the nerve ending and binds onto the muscle cell
What does ACH binding to muscle cell do and then trigger?
causes sodium channels to open allowing sodium to flow inside sacroplasm which triggers and action potential in sacrolemma
sarcoplasm
cytoplasm of a muscle cell
sacrolemma
cell membrane of muscle fiber
sacroplasmic reticulum
a specialized smoother ER found in striated muscle tissue
What is caused by the action potential of the sacrolemma?
calcium ions are released from the sacroplasmic reticulum which triggers the cross-bridges of myosin to rapily attach and reattach to actin filament pulling them along
What is needed on a cellular level for myosin cross-bridges to pull the actin filaments?
ATP
What happens when muscle contraction ceases?
nerve impulses no longer stimulate the muscle fiber, muscle action potential stops, and calcium ions are pumped back into the sarcoplasmic reticulum by active transport.
