THE MUSCULAR SYSTEM

Muscle is a type of tissue composed of contractile cells, or fibers that effects movement of an organ or body part. The amazing characteristic of muscular tissue is its ability to shorten or contract. A mucsle also has the properties of irritability, conductivity and elasticity. Our muscles have three basic functions. MOVEMENT which includes actions like talking, chewing, swallowing, eye movement, breathing, movement of vocal chords and the movement of blood and lymphatic fluid. The next function is HEAT PRODUCTION. Activity of our muscles is very important in creating the heat that warms us. Our muscles equal up to 40% of our total weight and burns more energy in the form of heat than any other body system. The last basic function is POSTURE. Our muscles actually help to link our skeletal system together. Muscles keep us balanced by contracting constantly to counter gravitational forces! Did you know that there are different types of muscle tissue?

The three types of muscle tissue are SMOOTH- (Involuntary-not under conscious control)digestive tract, urinary bladder, wall of blood vessels; CARDIAC- cardiac muscle fibers branch out forming a continuous network. At intervals prominant bands cross the fibers. Specialized fibers called PURKINJE form the impulse conducting system of the heart. and SKELETAL/STRIATED- (VOLUNTARY-conscious movement)striated muscle is found in all skeletal muscles. It is also found in the tongue, pharynx and upper esophagus. The musculoskeletal system is made up of muscles that have an attachment to the skeletal system. There are more than 600 muscles in the musculoskeletal system. Muscles may be attached directly to the periostium of the bone or it may be attached by tough cords of connective tissue called tendons or broad flat sheets called aponeuroses. The connective tissue enclosing a muscle is known as the epimysium which is continuous with the deep FASCIA.

AXIAL skeletal muscles control our facial expressions; chewing; eye, tongue and neck movements; respiration; the abdominal wall; the pelvic region; and movement of the vertebral column. The APPENDICULAR skeletal muscles include our pectoral girdle, pelvic girdle and our upper and lower extremeties. MUSCLE METABOLISM- All cells consume energy in order to perform work.

Adenoside triphosphate (ATP) , the source of chemical energy is metabolized to adenosine diphosphate (ADP). If energy demands are short term, ADP reverts to ATP. This process is too slow if energy requirements are more demanding, so consumption of other fuels is needed. The main source of fuel for muscles is carbohydrates and lipids (fats). When you are resting or exercising lightly, muscle metabolism is usually aerobic, using the free fatty acids in the plasma. When you exercise intensely, metabolism of fatty acids cannot keep up with the demand, so GLYCOGEN is used. If strenuous exercise cintinues, glycogen stores are exhausted, then fatty acids again become the main energy source.

MORE FACTS ABOUT MUSCLES
A muscle contracts and in response to a nerve stimulus. Once the nerve stimulus ends, the muscle relaxes and elastic fibers allow it to return to its normal position. Muscles are classified according to fiber arrangement and tendenous attachments. The main categaries are : OBLIQUE, CONVERGENT, CIRCULAR, and PARALLEL.
Did you know that each tiny muscle cell is encapsulated in a membrane called a sarcolemma? and within each cell are hundreds of long, thread-like structures called myofibrils, which run parallel to eachother. Then each MYOFIBRIL is made of smaller strands called MYOFILAMENTS. These strands are the basis of muscle contraction. OK enough.

COMMON DISORDERS/CONDITIONS OF THE MUSCULAR SYSTEM
MUSCULAR DYSTROPHY- One of nine syndromes that affect muscular strength and action. Some symptoms appear in infancy and other symptoms may start in adolesence or adulthood. These syndromes are identified by either generalized or localized muscle weakness, problems with walking and maintaining posture, and muscle spasms. In some cases there are neurological, behavioral and cardiac or other functional problems. MORE INFO : MUSCULAR DYSTROPHY ASSOCIATION website at www.mdausa.org.
ROTATOR CUFF TENDONITIS- common cause of shoulder pain
thought to be caused by the inflammation of intrinsic tendons of the shoulder. The start of symptoms follows injury or overuse during repeated over head arm movement as with certain jobs :painters, construction workers; and sports:baseball, tennis, swimming. People over 40 are at increased risk due to decresed blood supply to the rotator cuff tendons. Symptoms include pain with overhead motion, with decreased muscle strength. Moist heat and strengthening range of motion exercises, under a doctor's direction, are helpful.

MAINTAINING HEALTH OF THE MUSCULAR SYSTEM

Exercise regularly in moderation. Warm up first, always. Join a yoga or tai chi group / class. This practice is good for mind and body.

Eat lots of fresh and dried fruits-a good source of carbohydrates for ready muscle fuel;
Add nuts, seeds and avocados for healthy source of fats for additional fuel for muscles.
Include sources of muscle-building protein: fish, organic meats, tofu, beans, lentils, quinoa.
REFERENCES: Tabor's Cyclopedic Medical Dictionary,Edition 19, F.A. Davis; Anatomy Reference Guide, Lippincott, Williams and Wilkins