The Muscular System Support Systems Unit 2

Vocabulary- combining forms Cardi/o heart Fasci/o fascia, connective tissue Fibr/o fiber, fibrous tissue Leiomy/o smooth muscle Muscul/o muscle My/o muscle Ten/o, tend/o, tendin/o tendon

Vocabulary- prefixes A- or an- without or not Ab- away Ad- towards Bi- two Hemi- half Hyper- excessive, above normal Intra- within Quadri- four Tri- three

Vocabulary- suffixes -algia pain -ar pertaining to -ceps heads -cyte cell -ductionact of leading -genesis production of -itis inflammation -oma tumor -osis abnormal condition -pathy disease -plasty surgical repair -plegia paralysis -rrhaphy sutures -rrhexis rupture -tome instrument to cut -tomy incision -trophy development, nourishment -um structure, thing

Vocabulary- abbreviations and terms MRI magnetic resonance imaging Antagonist the muscle that does the opposite motion Agonist prime mover, the muscle that does most of the work Insertion the distal attachment/ the moving end Involuntary does not need conscious thought Origin the proximal attachment/ the stable end Striations striped Synergist helper muscle Thermogenesis heat production Voluntary needs conscious thought

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 can 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

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

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 (typically) Cardiac fibers typically have a centrally located nucleus Intercalated discs –Strengthens cardiac muscle tissue –Allows for special wringing muscle contraction

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)

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

Tendons Connect muscle to bone Made of dense fibrous connective tissue that surrounds the muscle belly and extends further, becoming tendon

Muscle Actions Agonist- the prime mover, or the muscle that does the most work Antagonist- the muscle that does the opposite motion Fixator- holds the body part in place while the action takes place Synergist- the helper muscle, assists in making the motion happen

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 Circumduction - cone shaped motion

Origin vs. Insertion Origin- the most proximal end of the muscle, the non moving end, or where the muscle starts Insertion- the distal end of a muscle, the moving end, or where the muscle goes to

Location and Function of Skeletal Muscles Biceps Brachii –Origin: anterior shoulder –Insertion: anterior elbow –Action: elbow flexion Triceps Brachii –Origin: posterior shoulder –Insertion: posterior elbow –Action: elbow extension

Location and Function of Skeletal Muscles Trapezius –Origin: cervical and thoracic spine –Insertion: spine of the scapula –Action: extends or hyperextends the head and neck, (also helps with shoulder retraction and elevation and depression) Latissimus Dorsi –Origin: Lower thoracic and lumbar spine as well as the pelvis –Insertion: proximal humerus –Action: extends a flexed arm or hyperextends the arm from the anatomical position

Location and Function of Skeletal Muscles Deltoid –Origin: clavicle and spine of the scapula –Insertion: lateral humerus –Action: shoulder abduction Pectoralis Major –Origin: upper ribs along the sternum and clavicle –Insertion: humerus –Action: adduction

Location and Function of Skeletal Muscles Rectus Abdominis –Origin: anterior lower ribs –Insertion: pubic bones –Action: lumbar spine flexion Diaphragm –Origin: central tendon (fibrous tissue) –Insertion: circumference of lower rib cage –Action: expands chest for breathing

Location and Function of Skeletal Muscles Quadriceps (group of 4 muscles) –Origin: anterior pelvis and proximal femur –Insertion: anterior tibia –Action: knee extension Hamstrings (group of 3 muscles) –Origin: ischium and posterior femur –Insertion: posterior tibia and fibula –Action: knee flexion

Location and Function of Skeletal Muscles Gluteus Maximus –Origin: ilium, sacrum, and coccyx –Insertion: femur –Action: extends hip Gastrocnemius –Origin: femur –Insertion: calcaneus (heel bone) –Action: plantar flexes ankle (when knee is straight) Soleus –Origin: tibia and fibula –Insertion: calcaneus (heel bone) –Action: plantar flexes ankle (when knee is bent)

Anterior Skeletal Muscles

Posterior Skeletal Muscles

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).

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 –1st degree occurs when the muscle is stretched causing micro-tears in the muscle fibers –2nd degree sprain occurs when the muscle or tendon is partially torn –3rd degree sprain occurs when the muscle is completely ruptured Signs and symptomsSigns and symptoms –Pain, especially when the muscle is contracting which limits function, swelling, and bruising TreatmentTreatment –Rest, Ice, Compression, 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

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.