Chapter 7 Muscular System

Functions of Muscular System Body heat to maintain body temperature Body movement Body form and shape to maintain posture

Types of Muscles Skeletal muscle Smooth muscle Cardiac muscle Under conscious control Smooth muscle Not under conscious control Cardiac muscle In the heart only

Animation – Types of Muscle Tissue Click Here to play Types of Muscle Tissue animation

Characteristics of Muscles Contractibility Excitability or irritability Extensibility Elasticity

Muscle Attachments and Functions Over 650 muscles in the body Muscles must be attached to bones for leverage Muscles only pull, never push Attached to bone by tendons

Muscle Attachments and Functions Muscles are attached at both ends Attachments may be to bones, cartilage, ligaments, tendons, skin or to each other Origin and insertion Prime mover and antagonist Synergists

Sources of Energy and Heat Narrow range of normal body temperature 98.6 °F to 99.8°F ATP (adenosine triphosphate) Need oxygen, glucose, and other material to make By-product is lactic acid

Contraction of Skeletal Muscle Myoneural stimulation Contraction of muscle proteins

Effects of Aging Muscle atrophy Fibrous tissue replaces the muscle tissue Decrease in muscular strength and endurance Loss of energy storage Fatigue

Muscle Fatigue Caused by accumulation of lactic acid in the muscles When not enough oxygen can be transported to oxidize all the glucose Muscles contract anaerobically Excess lactic acid causes fatigue and cramps Need to repay oxygen debt

Muscle Tone Muscle tone Proper nutrition and regular exercise Isotonic Muscles are always slightly contracted and ready to pull Proper nutrition and regular exercise Isotonic Isometric Atrophy and hypertrophy

Principle Skeletal Muscles Skeletal or voluntary muscles Move the skeleton Also control movement of the eyeballs, eyelids, lips, tongues, and skin

Naming of Skeletal Muscles Location Size Direction Number of origins Location of origin and insertion Not all muscles are named by above method

Muscles 656 muscles 327 antagonistic muscles and two unpaired muscles Orbicularis oris Diaphragm

Muscles Head muscles Neck muscles Trunk and extremity muscles

Muscles of the Head and Neck Control expressions Mastication Movement of the head

Muscles Muscles of the upper extremities Muscles of the trunk Shoulder, arm and hand movements Muscles of the trunk Breathing and movement of the abdomen and pelvis Muscles of the lower extremities Thigh, leg, ankle, foot, and toes

Exercise Alters the size, structure, and strength of a muscle Atrophy Hypertrophy Scar formation from injury

Exercise Improved coordination Improved respiratory and circulatory system Elimination or reduction of excess fat Improved joint movement

Exercise Increase in muscle size Improved antagonistic muscle coordination Improved functioning in the cortical brain region, where the nerve impulses that start muscular contraction

Massage Muscles Potential health benefits Terms used in massage therapy to describe type of massage Location of surface body muscles Physiotherapy and general massage

Electrical Stimulation Passing electrical currents through the skin into the body for therapeutic uses Stimulate nerve tissue Do not produce heat or cold Used in physical therapy

Intramuscular Injections Deltoid (upper arm) Vastus lateralis (anterior thigh) Dorsal gluteal or ventral gluteal (buttocks)

Musculoskeletal Disorders Muscle atrophy Muscle strain Muscle spasm Myalgia Hernia

Musculoskeletal Disorders Flatfeet (talipes) Tetanus (lockjaw) Torticollis (wry neck) Muscular dystrophy Myastenia gravis

Recreational Injuries Tennis elbow Shin splints Rotator cuff disease

Treatment Short term treatment for sprains, tears, pulls and other minor muscle of joint injuries RICE R – Rest I – Ice C – Compression E – Elevation