Muscular System

Skeletal muscles and touches on smooth muscle

Describe origin

Insertion of attachment, does not move

Describe insertion

Attachment that moves

Describe synergist muscles

Does the exact same action (biceps)

Describe antagonist muscles

Does the exact opposite action of synergist muscles (tricepts)

List the anatomy of a muscle cell

Sarcolemma (PM of the muscle cell), t-tubule (brings action potention to the center of the cell), multiple peripheral nuclei (store DNA, make RNA), sarcoplasmic reticulation (store and release calcium), mitochondria (create ATP to power cell), myofibrils (organized cytoskeleton that allows for contraction; thick and thin myofilaments), neuron (neuronmuscular junction - brings action potential from brain to activate the muscle)

List the steps of muscle contraction

Myosin head binds to actin, power stroke, bring the actin closer together; The sarcomere shortens but the filaments stay the same size

When can myosin bind to actin

When calcium is present

List the organization of myofilaments

Thick myofilaments (myosin), thin myofilaments (actin), z-disk (dystrophin), titin proteins, sarcomere (z-disk to z-disk)

What is a motor unit

A neuron and all of the fibers it attaches to

What is the cross section of a muscle

Epimysium (dense irregular CT, continuous with tendons), muscle, perimysium (moderately dense CT), fascicles (bundles of muscle fibers), endomysium (areolar CT), muscle fibers (cells), satellite cells (muscle stem cells, heal if you tear them), nerve (bundles of neurons, controls contraction)

Describe hypertrophy

Growth in size of muscle fibers, active muscles

Describe atrophy

Reduction of size, inactive muscles

Describe skeletal muscle

Moves the body, striated, cylindrical cells, multi-nucleated, voluntary, strong contractions (tire easily), contract 25-35% of length, heals quickly, actin and myosin are neatly organized

Describe smooth muscle

Walls of organs, non-striated, tapered cells, uni-nuclear, involuntary, weaker contractions (do not tire), contract 50% of length, heals slowly, actin and myosin are not neatly organized

What are the types of fascicle arrangements

Parallel, convergent, circular, unipannate, bipennate, multipennate

Describe parallel fascicle arrangement

Goes straight, longest distance of contraction, the WEAKEST

Describe convergent fascicle arrangement

Fans out

Describe circular fascicle arrangement

Anywhere you have sphincters (ex: mouth and eyes), (weakest, non-existent)

Describe unipennate fascicle arrangement

Fascicles on ONE side of one ligament

Describe bipennate fascicle arrangement

Fascicles on BOTH sides of one ligament

Describe multipennate fascicle arrangement

Fascicles on BOTH sides of MULTIPLE ligaments, shortest distance of contraction, the STRONGEST

First class lever system

Fulcrum is in the middle, no set of force or distance

Second class lever system

Center weight is in the middle, force advantage, distance disadvantage

Third class lever system

Center force is in the middle, force disadvantage, distance advantage

What is the formula for force

(Force of muscle)(Distance between CF and fulcrum) = (Weight moved)(Distance between CF and fulcrum)

What is the formula for distance

(Distance moved by muscles/Distance between CF and fulcrum) = (Distance moved by body part/Distance between CF and fulcrum)

Why do muscles of the same joint have opposite class lever systems

To cancel each other out and create a stronger joint