The Muscular System Support Systems Unit 2

Vocabulary- word parts My/o- muscle (myofibril is a muscle fiber) Ab- prefix, away (abduction) Ad- prefix, towards (adduction) Bi- prefix, two (biceps) Tri- prefix, three (triceps) Quad- prefix, four (quadriceps) Contra- prefix, opposite or against (contralateral- pertaining to the other side) Dys- prefix, bad, difficult, or painful (dysphagia- difficulty swallowing) -algia- suffix, pain (myalgia- muscle pain)

Vocabulary Ligament- connective tissue that holds bone to bone Tendon- connective tissue that hold muscle to bone Tendonitis- inflammation of a tendon Sprain- stretch or tear of a ligament Strain- stretch or tear of a muscle or tendon Myocardium- heart muscle Thermogenesis- heat production Striations- stripes MRI- Magnetic Resonance imaging

Functions of the Muscular System Heat Production (thermogenesis) –Heat is a byproduct of muscle contraction Movement Facilitation –Muscles shorten and pull on bones which produces movement Structure (postural support) –Contraction of muscles keeps us upright and maintains posture

Functions cont. Protection of Internal Organs –Contraction of abdominal muscles causes them to become hard and offers protection to the underlying organs –Other muscles con contract prior to receiving a blow thus protection bones and soft tissue. Controls the volume of hollow organs –Smooth muscle surrounds our hollow organs and contractions propel the substances through them, aid in their emptying, or helps control their volume Stomach and small intestines The bladder Blood vessels

Anterior Skeletal Muscles

Posterior Skeletal Muscles

Types of Contractibility Voluntary - contractions controlled by conscious thought or will Involuntary - contract due to unconscious impulses sent by the autonomic nervous system or certain specialized cells or hormones

Types of Muscles

Muscle Appearance Striated - stripes, muscles that on a microscopic level have cross fiber stripes Non-striated - Not having stripes, muscles cells that microscopically have a smooth appearance

Cardiac Muscle Forms the bulk of heart wall (Myocardium) Striated Involuntary Cardiac fibers typically have a centrally located nucleus Intercalated discs –Strengthens cardiac muscle tissue –Allows for special wringing muscle contraction

Cardiac Muscle Tissue

Smooth Muscle Located in walls of hollow internal surfaces such as: –blood vessels- stomach –urinary bladder- intestines Non-striated in appearance Involuntary (typically) Contractions usually move things along, from point A to point B (peristalsis)

Smooth Muscle Tissue

Skeletal Muscle Attached to bones Striated appearance under a microscope Voluntary control (conscious control) Allow for postural support and movement of body parts, both axial and appendicular

Skeletal Muscle Tissue

Connecting Tissues Tendon – muscle to boneLigament- bone to bone

Motions Peristalsis - a wave like motion by smooth muscle to advance substances Abduction - movement away from midline Adduction - movement towards midline Flexion - decreasing a joint angle Extension - increasing a joint angle Hyperextension - extension past normal extension, or past anatomical position

Motions Plantarflexion- specific to ankle motion, pointing the toes Dorsiflexion- specific to ankle motion, pulling the toes towards the shin Supination- turning palm up Pronation- turning palm down Rotation - movement around an axis

Location and Function of Skeletal Muscles Biceps brachii- anterior surface of arm between the shoulder and elbow, flexes the elbow Triceps brachii- posterior aspect of arm between the shoulder and elbow, extends the elbow Sternocleidomastoid – rotates head right and left Trapezius- attaches to the spine from the occiput through the thoracic region and to the spine of the scapula, extends or hyperextends the head and neck, (also helps with shoulder retraction and elevation and depression) Deltoid- covers the cap of the shoulder, abducts the arm Diaphragm- connects to the lower ribs and runs through the entire body, deflects the diaphragm inferiorly increasing volume of the thoracic cavity

Location and Function of Skeletal Muscles Pectoralis major- attaches to the upper ribs along the sternum and to the humerus, adducts the arm Latissimus dorsi- attaches along mid to lower spine and pelvic and to the humerus, extends a flexed arm or hyperextends the arm from the anatomical position Rectus abdominus- attaches to the lower ribs and to the pelvic anteriorly, flexes the lumbar spine Gastrocnemius-attaches to the tibia and lower femur and uses the achilles tendon to attach to the calcaneous (heel bone), plantar flexes the ankle when the knee is in extension

Location and Function of Skeletal Muscles Soleus- attached deep to the gastrocnemius on the tibia and uses the achilles tendon to attach to the calcaneous, plantarflexes the ankle when the knee is bent Hamstrings- posterior thigh between the hip and knee, flexes the knee – three muscles (Semimembranosus, Semitendenosus, Bicep Femoris) Quadriceps- anterior thigh between the hip and knee, extends the knee - four muscles (Vastas Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris) Sartorius – longest muscle in the body – attach at the illiac crest and inserts below the medical knee. Externally rotates hip and flexes the knee (figure 4 pos) Gluteus maximus- posterior pelvis, extends a flexed thigh or hyperextends the thigh from the anatomical position

Diseases and Disorders of the Muscular System

Tendonitis Tendonitis is characterized by Inflammation of the tendons due to overuse or age-related changes of the tendon. It is common in individuals who begin a new exercise or increase their level of exercise. Age-related tendonitis is due to the loss of elasticity and the ability of the tendon to glide smoothly. Treatment includes: rest, ice, compression, and elevation (RICE).

Muscle Spasm An involuntary muscle contraction Also called a “Charlie Horse” or “muscle cramp” Main causes are electrolyte imbalances, dehydration and fatigue

Muscle Spasm cont. Initial treatment is to put the muscle that has the spasm on stretch –If spasm persists ice or heat can be used Prevention incudes maintaining a proper diet, drinking plenty of water and proper conditioning –Sports drinks may be beneficial during exercise to help replace lost sodium due to sweating

Strains A tearing of a muscle or its attaching tendon Occurs when a muscle receives a stress that overcomes its strength –Sudden, quick heavy lifting –During sports –While performing work tasks

Strains cont. 3 types of strains3 types of strains 1 st degree occurs when the muscle is stretched causing micro-tears in the muscle fibers1 st degree occurs when the muscle is stretched causing micro-tears in the muscle fibers 2 nd degree sprain occurs when the muscle or tendon is partially torn 2 nd degree sprain occurs when the muscle or tendon is partially torn 3 rd degree sprain occurs when the muscle is completely ruptured3 rd degree sprain occurs when the muscle is completely ruptured Signs & symptoms include:Signs & symptoms include: Pain, especially when the muscle is contractiong which limits functionPain, especially when the muscle is contractiong which limits function SwellingSwelling BruisingBruising Treatment includes Rest, Ice, Compression, ElevationTreatment includes Rest, Ice, Compression, Elevation

Muscular Dystrophy An inherited disorder in which the muscles are missing a certain protein causing degeneration of muscle tissue Causes progressive weakness and loss of function of the affected muscles There is no cure but physical therapy can lessen the severity of the disorder.

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