Muscular system Test

Cardiac muscle

Found only in the heart, striated, involuntary, arranged in figure 8 shaped bundles (for contraction), intercalated disks

Smooth muscle

Visceral (hollow organs), non striated involuntary, arranged in sheets or layers (contract change shape of organ)

Involuntary

Muscles we can't control and just happens

Skeletal muscle

Where muscle connects to bone for movement, striated, voluntary( only muscle in muscular system)

Origin

Part of the muscle attached to the immovable or less movable bone

Insertion

Part attached to the movable bone; insertion moves toward the origin

Flexion

Decrease angle of a joint (hinge joints - knee & elbow)

Extension

Increases angle of a joint (straighten knee or elbow)

Rotation

Movement of a bone around its longitundial axis (ball & socket joints)

Abduction

Moving a limb away from the midline (raising arm or leg out to the side)

Adduction

Moving a limb toward the midline (lowering arm or leg from the side back down to the body)

circumduction

Proximal end of a limb is stationary, distal end moves in a circle, combination of flexion, extension, abduction, & adduction

Dorsiflexion

Lifting the foot so that its superior surface approaches the shin

Plantar flexion

Depressing the toes (point the foot)

Inversion

Turn the sole medially (most common type of ankle sprain)

Eversion

Turn the sole laterally

Supination

Forearm rotates laterally so palm faces anteriorly; radius & ulna are parallel

Pronation

Forearm rotates medially so palm faces posteriorly ; radius & ulna form an X

Opposition

Movement of thumb when touching tips of other fingers on same hand

Prime mover

Muscle that has the major responsibility for causing a particular movement

Antagonist

Muscles that oppose or reverse a movement

synergists

Help prime movers by producing same movements

Fixators

Hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone

Direction of the muscle fibers

Usually a reference to a midline or long axis of a limb

Relative size of the muscle

Maximus, minimus, longus

Location of the muscle

Named for bone associated with the muscle (temporalis, tibialis)

Number of origins

Biceps brachii, triceps brachii

Location of muscle's origin & insertion

Sternocleidomastoid originates on sternum & clavicle, inserts on mastoid process of temporal bone)

Shape of the muscle

Deltoid means triangular

Action of the muscle

Flexor, extensor, adductor, etc.

Endomysium

Delicate connective tissue sheets that encloses each muscle fiber

Perimysium

Coarser fibrous sheeth that surrounds muscle fiber bundles called fascicles

Epimysium

Covers bundle of fasciculi (entire muscle) blends into either

Tendon

Cord of dense, fibrous tissue attaching a muscle to a bone

Sarcolemma

Cell membrane of muscle fiber (cell) under the endomysium

Peripheral nuclei

Nuclei are pushed aside by myofibrils

Myofibrils

Long rope-like organelles made of tiny contractile units called sarcomeres

Myosin filament

Thick

Actin filament

Thin

Z line

Thin filaments at either end of sarcomere attached to interconnecting proteins, thin filaments extend from Z line

M line

Proteins connect center of each thick filaments

A band

Area containing thick filaments, includes some overlap with thin filaments (appears dArk)

H zone

Area containing only thick filaments in center of A band

I band

Area containing only thin filaments, including Z line (appears lIght)

Transverse tubules

Openings along the sarcolemma that form passageways through the muscle fiber/transmit action potential through cell & allow entire muscle fiber to contract simultaneously

Sarcoplasmic reticulum

Specialized form