THE MUSCULAR SYSTEM Part 1 JOSE A.S. SANTIAGO M.D.

The Muscular System Muscles are responsible for all types of body movement Three basic muscle types are found in the body Skeletal muscle -voluntary Cardiac muscle - involuntary Smooth muscle (Visceral) - involuntary

Nerve stimulus to muscles Skeletal muscles must be stimulated by a nerve to contract Motor unit One neuron Muscle cells stimulated by that neuron

Nerve stimulus to muscles Neurotransmitter – chemical released by nerve upon arrival of nerve impulse The neurotransmitter for skeletal muscle is acetylcholine

Types of muscle contractions Isotonic contractions The muscle shortens Isometric contractions Tension in the muscles increases The muscle is unable to shorten

Skeletal Attachments Origin Insertion - Attachment to immovable bone - Attachment to movable bone

Skeletal Attachments 1. Ligaments 2. Tendons (cord-like structure) Bone to bone 2. Tendons (cord-like structure) Muscle to bone

Tenosynovium Tendon sheath - covering of a tendon

Tenosynovitis Inflammation of the tendon sheath

Skeletal Attachments 3. Aponeuroses - Flat, sheet-like structure

Connective Tissue Wrappings of Skeletal Muscle 1. Endomysium – around single muscle fiber 2. Perimysium – around a fascicle (bundle) of fibers

Connective Tissue Wrappings of Skeletal Muscle 3. Epimysium – covers the entire skeletal muscle Figure 6.1

Connective Tissue Wrappings of Skeletal Muscle 4. Fascia - on the outside of the epimysium - band of tissue surrounding the muscle Figure 6.1

Fasci /o - fascia Fascial - pertaining to the fascia Fasciectomy - excision of the fascia Fascitis - inflammation of the fascia Fasciorrhaphy -repair of the fascia

Types of Ordinary Body Movements Flexion- bending a limb Extension- stretching out a limb Rotation- turning of body part about its axis Abduction- drawing away from Adduction- drawing toward Circumduction- movement in a circular motion

Body Movements

Special Movements Dorsiflexion- bending the foot upward Plantar flexion- foot bends toward the sole Inversion- foot rotated inward Eversion- foot rotated outward Supination- turning the palm forward Pronation- turning the palm backward Opposition- moving the thumb opposite to the fingers

Naming of Skeletal Muscles Direction of muscle fibers Example: rectus (straight) Relative size of the muscle Example: maximus (largest) Location of the muscle Example: many muscles are named for bones (e.g., temporalis) Number of origins Example: triceps (three heads)

Naming of Skeletal Muscles Location of the muscle’s origin and insertion Example: sterno (on the sternum) Shape of the muscle Example: deltoid (triangular) Action of the muscle Example: flexor and extensor (flexes or extends a bone)

Superficial Muscles: Anterior

Superficial Muscles: Posterior

Roots – Muscular Duct/o to draw Electr/o electric Fasci/o fascia Kinesi/o movement Lei/o smooth Muscul/o; my/o muscle

Electr/o - electric Myo- muscle -graphy process of recording Electromyography -process of recording the electrical activity of muscle

Kinesi/o - movement -logy - study of Kinesiology - study of movement -meter - instrument for measuring Kinesimeter - instrument for measuring movement

Lei/o - smooth My/o - muscle -oma - tumor Leiomyoma - benign tumor of smooth muscle

Leiomy/o - smooth muscle -sarcoma - malignant tumor of connective tissue Leiomyosarcoma - malignant tumor of smooth muscle

Muscul/o - muscle Muscular- pertaining to muscle Musculoskeletal- pertaining to muscle and skeleton

My/o - muscle -gram - record Electromyogram -record of the electrical currents in a muscle

My/o - muscle -algia - pain Myalgia – muscle pain

My/o - muscle -algia - pain Fibr/o - fiber Fibromyalgia - pain in fibrous tissues such as muscles, tendons and ligaments

My/o - muscle -pathy - disease Myopathy – any muscular disease

Myos/o - muscle -itis - inflammation Myositis -inflammation of muscle

Myos/o - muscle Poly - many Polymyositis -inflammation of many muscles

Rhabd/o - striped;striated -oma - tumor Rhabdomyoma -benign tumor of striated muscles

Rhabd/o - striped;striated Rhabdomyosarcoma -malignant tumor of striated muscles

Rhabd/o - striped;striated -lysis - breakdown Rhabdomyolysis -breakdown of striated muscle tissue

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