Muscular System Flashcards
What must be present in order for a muscle cell to contract?
Calcium and ATP
Synergists:
Work in cooperation with the prime mover
Flexors:
Reduce the angle at the joint
Extensors:
Increase the angle at the joint
Abductors:
Draw a limb away from the midline
Adductors:
Return the limb back toward the body
How do muscle cells contract?
- Nervous stimulation from motor neurons causes release of calcium ions from the sarcoplasmic reticulum
- Calcium ions attach to inhibitory proteins on actin filaments, moving them aside so cross-bridges can form between actin and myosin filaments
- Using energy supplied by ATP, the filaments slide together to produce contraction
Sarcomere:
Smaller subunits of myofibrils, contractile
Skeletal muscles (which make up the muscular system) must work in pairs:
The muscle that executes movement is the prime mover.
The muscle that produces the opposite movement is the antagonist.
Myofibril:
Tightly packed filament bundles found within skeletal muscle fibers
Dorsiflexion:
Ankle flexion (moving the toes toward the shin)
Plantar flexion:
Ankle extension (moving toes toward the ground/pointing the toes)
Myosin:
Thick filaments
Actin:
Thin filaments
Insertion:
Attachment to movable bone
Origin:
Attachment of the muscle to the bone that remains stationary
Motor neurons of the ANS consist of 2 neurons:
Preganglionic and postganglionic
Smooth (visceral) Muscle:
- Nonstriated
- Involuntary
- Found inside: organs, blood vessel, and airway walls
Cardiac Muscle:
- Striated
- Involuntary
- Arrhythmic
- Interconnected
Skeletal muscle is:
Striated and voluntary
Quadricep muscles:
Vastus lateralis (lateral) Vastus intermedius (intermediate) Vastus medialus (medial)
