Muscle

• Skeletal:

o   Attached to the bone, supports and moves the skeleton

o   Fibers are striated, tubular, and multinucleated as well as parallel and long.

o   Actions are voluntary

• Cardiac:

o   The muscle of the heart propels blood through the circulatory system

o   Fibers are striated, branched, and uni-nucleated.

o   Actions are involuntary

• Smooth:

o   Surrounds hollow organs of the body, controls the movement of contents through the organ and is capable of slow and sustained contractions

o   Fibers are non-striated, spindle-shaped, and uni-nucleated.

o   Actions are involuntary

• Layers:

o   Muscle/Epimsyium: Outermost connective tissue sheath, surrounding the entire muscle.

o   Fascicle/Perimysium: Connective tissue sheath covering fasciculus.

o   Endomysium: Innermost sheath at individual muscle fibers.

o   External Lamina

o   Muscle Fiber/Sarcolemma

o   Myofibril/ Sarcomere

o   Myofilaments/Actin and Myosin

• The architecture of muscles:

o   Flat: Have parallel fibers

o   Pennate: Featherlike, it can come as unipennate, bipennate and multipennate.

o   Fusiform: Spindle-shaped

o   Convergent: A broad area converging to a single tendon.

o   Quadrate: Has four equal sides

o   Circular: Surrounds a body opening or orifice

o   Multi-headed/bellied: More than one head of attachment.

Contractions

• Reflexive Contractions: Involuntary muscles.

• Tonic Contractions: When relaxed it’s still contracted.

• Phasic Contractions: Active muscle contractions

o   Isotonic: Muscles change in relation to movement.

• Concentric Contractions: Muscle tension rise to meet the resistance and remains stable as the muscle shortens.

• Eccentric Contractions: Muscle lengthens as resistance becomes greater than the force the muscle is producing.

o   Isometric Contractions: Muscle length remains the same, no movement occurs but the force is increased to tonic levels.

• Roles:

o   Prime mover: Responsible for producing specific movement

o   Fixator: Steadies the limb during isometric contractions

o   Synergist: Complements the action of the prime mover

o   Antagonist: Opposes the action of another muscle

o   Shunts: Maintaining contact between articular + joints

Skeletal Systems

• Cartilages:

o   Semirigid is an avascular form of connective tissue located in areas where flexibility is required. Their functions are supporting soft tissues, providing a smooth gliding surface for bone articulations at joints as well as enabling the development and growth of long bones.

o   There are three types:

§  Hyaline: Most common and found in ribs and trachea.

§  Elastic: Found in intervertebral discs and joint capsules.

§  Fibrocartilage: Located in the external ear and epiglottis.

• Bones:

o   Vascular, rigid connective tissues form the majority of the skeletal system. Their functions are the supportive structure for the body, protecting organs and containers for Ca and P as well as blood-producing cells.

o   There are 2 types - Compact and Spongy

Joints

• Joints: Can be classified into two ways:

o   Functionally:

§  Synarthroses - Immovable

§  Amphiarthrosis - Partially movable

§  Diarthroses - Freely Movable

o   Type Of Material:

§  Synovial - Joint

§  Fibrous - Fibrous

§  Cartilaginous - Fibrocartilidge/Hyaline (Synchandroses present between ribs and sternum, Symphyses present in the vertebral disk.