Muscular System

• Movment Breathing
• Posture
• Heat Production

the site where motor neuron and muscle fiber meet

• 1. Axon Terminal--neurotransmitter-release acethylcholine (ACh)
• 2.Synaptic cleft is the space
• 3. Motor end plate(MEP)--> modified sarcolemma--contains ACh receptors
• Acetylcholinesterase is an acethylcholine degrading enzyme.

Sarcomere--> the smallest functional unit

Thin filament--is made of actin and attached to Z-disc

Thick filament-- is made of myosin and is centeral location

Sliding Filament Theory is when the actin and mysoin bind--> thin fliament move over thick filaments and the sarcomere shortens

Requirement for relaxation is ATP.

• Motor Unit is motor neuron & all muscle fibers it stimulates
• All-or-none law is when the maximum contraction of all fibers in the motor unit.
• Recruitment is increased motor units and increased contraction force

• Twitch is a rapid response of a muscle fiber to a threshold stimulus.
• Tetanus is substaned contraction due to rapid stimulation and summation of twitches (prolonged contraction of skelectal muscles)

Refactory period is the period which a threshold stimulus produces no response.

length = short

Endurance Exercise is aerobic metabolism without interruption for long periods of time. This promotes physical fitness.

Physical Fitness is the ability to do work.

This is overwhelmingly related to changes in skelectal muscles (not heart or lungs) that allow it to use oxygen more efficiently.

• Vertebral column
• ---sternocleiodomastoid (flexes)
• ---abdominals (flex): rectus adominis, external oblique, internal oblique

• Upper Extremity at shoulder
• ----pectoralis major (flexes)
• ----deltoid(abducts)
• ----latissimus dorsi(extends)

• Lower extremity at hip & knee
• ----sartorius (flexes at hip & knee)
• ----quadriceps group (extend at knee)
• -----gluteus maximus (extends at hip)
• -----hamstrings group (extends at hip, flexes at knee)