Muscular System Functions Voluntary movement Forms some sphincters Protection of some organs Stabilization of some joints Posture Heat production

Muscular System Organs – Muscles

Muscular System Organs – Muscles (includes tendons and aponeuroses)

Structure of Skeletal Muscles – Muscle fibers

Structure of Skeletal Muscles – Muscle fibers

Structure of Skeletal Muscles – Muscle fibers Contractile units within:

Structure of Skeletal Muscles – Muscle fibers Contractile units within: – Sarcomeres

Structure of Skeletal Muscles – Muscle fibers Contractile units within: – Sarcomeres

Structure of Skeletal Muscles – Muscle fibers Contractile units within: – Sarcomeres – Sarcomeres linked end-to end

Structure of Skeletal Muscles – Muscle fibers Contractile units within: – Sarcomeres – Sarcomeres linked end-to end; form myofibrils

Muscle fibers bundled into fascicles

Fascicles bundled to form the muscle

Connective Tissue in Muscle

– Endomysium

Connective Tissue in Muscle – Endomysium – Perimysium

Connective Tissue in Muscle – Endomysium – Perimysium – Epimysium

How Muscles Create Movement at Joints – Muscles must cross joints – Insertion pulled towards origin

Fascicle Organization Parallel – Greatest range of motion

Fascicle Organization Parallel Pennate

Fascicle Organization Parallel Pennate – Strongest force of contraction

Fascicle Organization Parallel Pennate Convergent

Fascicle Organization Parallel Pennate Convergent – Greatest versatility

Fascicle Organization Parallel Pennate Convergent Circular

Muscle-Bone Lever Systems

F

F

R F

R F E Third-class lever Muscle-Bone Lever Systems

R F E Third-class lever Muscle-Bone Lever Systems

F E R Third-class lever

R F E

F E R

F E R Amplifies speed and distance at the expense of force

R F E Third-class lever Muscle-Bone Lever Systems

R F E Third-class lever Muscle-Bone Lever Systems

R F E Third-class lever Muscle-Bone Lever Systems

R F E Second-class lever Muscle-Bone Lever Systems

R F E First-class lever Muscle-Bone Lever Systems

Muscle Interaction Prime Mover – Muscle most responsible for an action e.g.: abduction of arm: deltoid

Muscle Interaction Synergistic muscles – Assists prime mover e.g.: supraspinatus assists deltoid in abduction

Muscle Interaction Fixator muscles – Holds bone of origin steady e.g.: serratus anterior holds deltoid’s bone of origin steady during abduction

Muscle Interaction Antagonistic muscles – Action opposite that of the prime mover e.g.: lats and pects adduct must not contract during abduction

Muscle names may indicate the direction of the muscle fibers (e.g., transversus abdominis, external oblique).

A muscle may be named according to its location (e.g., temporalis, tibialis anterior).

The size of the muscle may be indicated in the name (e.g., gluteus maximus, adductor Iongus).

Some muscles are named on the basis of shape (e.g., deltoid, serratus anterior). Muscles may be named after their origin and insertion (e.g., sternocleidomastoid).

A muscle may be named according to its location (e.g., temporalis, tibialis anterior). Muscles may be named for their number of origins (e.g., triceps brachii, quadriceps femoris).

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