Bio 3.4

Motor neuron in somatic division

Motor neuron in somatic division

PNS neurons receive CNS output information and carry signals to muscles

Muscles fascicles(tissues)

bundles of muscle tissue held together by connective tissue

Muscle fiber(cell)

multinucleate, long cells packed with cylindrical fibers

Sarcomere

actin(cytoskeleton)+myosin(motor proteins)

Each myofiber(muscle cell) is controlled by ____ motor neuron. But ___ motor neuron can control many muscle cells

one, one

What does motor neurons release at the neuromuscular junction via exocytosis

acetylcholine

First step in sliding filament mechanism

release of Ca2+ from reticula allows for binding between myosin and actin

2nd step in sliding filament mechanism

myosin heads, with bound ADP + P, attach to the actin filament

3rd step in siding filament mechanism

working stroke- myosin heads bend and pull on the actin filament, sliding it toward the middle of the sarcomere

Step 4 in sliding filament mechanism

a new ATP attaches to the myosin head, causing the head to detach from actin

Step 5 in sliding filament mechanism

as ATP is split into ADP + P which transfers energy. This energy is used to cock the myosin head in preparation for another movement

Atrophy

wasting away of muscles breakdown of myofibril content and lack of myofibril production

Hypertrophy

the more stress placed on muscle fibers, the more they will adapt by increasing their myofibril content

Slow twitch

a small diameter fiber cells that can contract incrementally for a relatively long time

Aerobic training

builds muscle cell endurance but does not increase muscle size

Fast twitch

large diameter fibers, split ATP rapidly for short bursts of concentration

Strength conditioning

exercises that strengthen muscles by making them work harder

High concentration of slow twitch

lean body type, aerobically inclined, can eat a lot and not cain weight

Balanced concentration

athletic body type, aerobically and anaerobically inclined, can put on fat easily

High concentration of fast twitch

aerobically unfit, greater strength, trouble lowering weight even with diet and exercise.