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The human body contains more than 650 individual muscles which are attached to the

skeleton, which provides the pulling power for us to move around. The main job of the

muscular system is to provide movement for the body. The muscular system consist of three different types of muscle tissues : skeletal, cardiac, smooth. Each of these different

tissues has the ability to contract, which then allows body movements and functions.

There are two types of muscles in the system and they are the involuntary muscles, andthe voluntary muscles. The muscle in which we are allow to control by ourselves are

called the voluntary muscles and the ones we can? control are the involuntary muscles.

The heart, or the cardiac muscle, is an example of involuntary muscle.

CARDIAC MUSCLE:

The cardiac muscles is the muscle of the heart itself. The cardiac muscle is the tissue thatmakes up the wall of the heart called the mydocardium. Also like the skeletal muscles,

the cardiac muscle is striated and contracts through the sliding filament method. However 

it is different from other types of muscles because it forms branching fibers. Unlike the

skeletal muscles, the cardiac muscle is attached together instead of been attach to a bone.

SKELETAL MUSCLE:

The skeletal muscle makes up about 40 % of an adults body weight. It has stripe-like

markings, or striations. The skeletal muscles is composed of long muscle fibers. Each of these muscles fiber is a cell which contains several nuclei. The nervous system controls

the contraction of the muscle. Many of the skeletal muscle contractions are automatic.

However we still can control the action of the skeletal muscle. And it is because of this

reason that the skeletal muscle is also called voluntary muscle.

SMOOTH MUSCLE:

Much of our internal organs is made up of smooth muscles. They are found in the urinary

 bladder, gallbladder, arteries, and veins. Also the digestive tract is made up of smooth

muscle as well. The smooth muscles are controlled by the nervous system and hormones.We cannot consciously control the smooth muscle that is why they are often called

involuntary muscles.

Muscular System

Navigation links

• Introduction

• Cardiac muscle

• Smooth muscle

• Skeletal muscle

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• Muscle fibers and exercise

Introduction

Over 600 skeletal muscles function for body movement through contraction and relaxation of voluntary, striated muscle fibers. These muscles are attached to bones, and are typically under 

conscious control for locomotion, facial expressions, posture, and other body movements.Muscles account for approximately 40 percent of body weight. The metabolism that occurs in thislarge mass-produces heat essential for the maintenance of body temperature.

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Cardiac muscle

Cardiac muscle is only in the heart and makes up the atria and ventricles (heart walls). Likeskeletal muscle, cardiac muscle contains striated fibers. Cardiac muscle is called involuntarymuscle because conscious thought does not control its contractions. Specialized cardiac musclecells maintain a consistent heart rate.

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Smooth muscle

Smooth muscle is throughout the body, including in visceral (internal) organs, blood vessels, andglands. Like cardiac muscle, smooth muscle is involuntary. Unlike skeletal and cardiac muscle,smooth muscle is nonstriated (not banded). Smooth muscle, which is extensively within the wallsof digestive tract organs, causes peristalsis (wave-like contractions) that aids in food digestionand transport.

Except the heart, any action that the body performs without conscious thought is done by smoothmuscle contractions. This includes diverse activities such as constricting (closing) the bronchioles

(air passages) of the lungs or pupils of the eye or causing goosebumps in cold conditions.

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Skeletal muscle

A skeletal muscle has regular, ordered groups of fascicles, muscle fibers, myofibrils, andmyofilaments. Epimysium (thick connective tissue) binds groups of fascicles together. A fasciclehas muscle fibers; perimysium (connective tissue) envelops the fascicle. Endomysium(connective tissue) surrounds the muscle fibers.

A muscle fiber divides into even smaller parts. Within each fiber are strands of myofibrils. These

long cylindrical structures appear striped due to strands of tiny myofilaments. Myofilaments havetwo types of protein: actin (thin myofilaments) and myosin (thick myofilaments).

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The actin and myosin myofilaments align evenly, producing dark and light bands on the myofibril.Each dark band depicts an area where the myofilaments overlap, causing the striatedappearance of skeletal muscle.

All dark and light bands of the myofilaments have names. At the Z-line, actin strands interweave.The region between two Z-lines is a sarcomere, the functional unit of skeletal muscle. Musclecontraction occurs when overlapping actin and myosin myofilaments overlap further and shortenthe muscle cell. The myofilaments keep their length. The overlapping of myofilaments is the basisfor the sliding filament theory of contraction.

Skeletal muscle is a system of pairs that relax and contract to move a joint. For example, whenfront leg muscles contract, the knee extends (straightens) while back leg muscles relax.Conversely, to flex (bend) the knee, back leg muscles contract while front leg muscles relax.Some muscles are named for their ability to extend or flex a joint; for example, extensor carpiradialis longus muscle and flexor digitorum brevis muscle.

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Tendons attach most skeletal muscles to bones. Tendons are strong sheets of connective tissuethat are identical with ligaments. Tendons and ligaments differ in function only: tendons attachmuscle to bone and ligaments attach bone to bone. Physical exercise strengthens the attachmentof tendons to bones.

Skeletal muscles have muscle tone (remain partly contracted), which helps maintain bodyposture. Ongoing signals from the nervous system to the muscle cells help maintain tone andreadiness for physical activity.

Skeletal muscle aids in heat generation. During muscle contractions, muscle cells expend muchenergy, most of which is converted to heat. To prevent overheating, glands in the skin producesweat to cool the skin; and, the body radiates heat from the blood and tissues through the skin.When the body is chilly, shivering causes quick muscle contractions that generate heat.

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Muscle fibers and exercise

Skeletal muscles have two types of muscle fibers: fast-twitch and slow-twitch. Anaerobic exerciseuses fast-twitch fibers. Such exercise includes activities that are fleeting and require brief high-energy expenditure. Weightlifting, sprinting, and push-ups are examples of anaerobic exercise.Because all cells require oxygen to produce energy, anaerobic exercise depletes oxygenreserves in the muscle cells quickly. The result is an oxygen debt. To repay the debt, humans

breathe deeply and rapidly, which restores the oxygen level. Anaerobic exercise creates excesslactic acid (a waste product). By increasing oxygen intake, the liver cells can convert the excesslactic acid into glucose, the primary food molecule used in cellular metabolism.

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Aerobic exercise uses slow-twitch muscle fibers. Such exercise includes activities that areprolonged and require constant energy. Long distance running and cycling are examples of aerobic exercise. In aerobic exercise, the muscle cell requires the same amount of oxygen thatthe body supplies. The oxygen debt is slashed and lactic acid is not formed.

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Muscle diseases

Myopathy

Myopathies are diseases of skeletal muscle which are

not caused by nerve disorders. These diseases

cause the skeletal or voluntary muscles to becomeweak or wasted. Myopathies are usually

degenerative, but they are sometimes caused by

drug side effects, chemical poisoning, or a chronicdisorder of the immune system.

 

Chronic fatigue syndromeChronic fatigue syndrome (CFS) is an illnesscharacterized by prolonged, debilitating fatigue

and multiple nonspecific symptoms such as

headaches, recurrent sore throats, muscle and joint

 pains, memory and concentration difficulties.Chronic fatigue syndrome is a debilitating and

complex disorder characterized by profound

Topics in bone, joint, and

muscle disorders

Bone diseases

Bone tumors

Bone cancer 

Muscle diseases

Spine (neck and back) disorders

Dupuytren's contracture

Costochondritis

Bunions

Plantar fasciitis

Arthritis

Osteoarthritis

Rheumatoid arthritis

Juvenile rheumatoid arthritis

Septic arthritis (infectious Arthritis)

Psoriatic arthritis

Reiter's syndrome (reactive

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fatigue of six months.

 

Fibromyalgia

Fibromyalgia is a debilitating chronic illness

characterized by diffuse pain, fatigue, and a wide

range of other symptoms. It is a syndrome, not adisease. It is not contagious, and is probablygenetic. It affects more women than men, mostly

 between ages 20 and 50. It is seen in 3-10% of the

general population.

 

Muscular dystrophy

Muscular dystrophy (MD) is a broad term that

describes a genetic (inherited) disorder of themuscles. Muscular dystrophy causes the muscles in

the body to become very weak. The muscles break 

down and are replaced with fatty deposits over time. Muscular dystrophy is a genetic disorder that

is characterized by muscle wasting and weakening.

 

Dermatomyositis

Dermatomyositis is one of a group of 

inflammatory muscle diseases. It is a subtype of 

inflammatory muscle disease. Dermatomyositismay affect people of any race, age or sex, although

it is twice as common in women than in men.

Dermatomyositis belongs to a group of conditionscalled inflammatory myopathies.

 

Polymyositis

Polymyositis is a systemic connective tissue disorder characterized by inflammatory and degenerative

changes in the muscles, leading to symmetric

weakness and some degree of muscle atrophy.Polymyositis is slightly more common in females.

It affects all age groups, although its onset is most

common in middle childhood and in the twenties.

 Rhabdomyolysis

Rhabdomyolysis is the breakdown of muscle fibers

resulting in the release of muscle fiber contents

into the circulation. Some of these are toxic to thekidney and frequenty result in kidney damage.

Many clinical features of rhabdomyolysis are

nonspecific, and the course of the syndrome varies

arthritis)

Ankylosing spondylitis

Gout (gouty arthritis) 

Tendinitis

Osteoporosis

Whiplash

Fibromyalgia

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depending on the underlying condition.

 

Compartment syndrome

Compartment syndrome involves the compression

of nerves and blood vessels within an enclosed

space. Compartment syndrome is a condition inwhich there is swelling and an increase in pressurewithin a limited space (a compartment) that presses

on and compromises blood vessels, nerves, and/or 

tendons that run through that compartment.

Neuromuscular disease is a very broad term that encompasses many diseases and

ailments that either directly, via intrinsic muscle pathology, or indirectly, via nerve 

 pathology, impair the functioning of the muscles.

 Neuromuscular diseases are those that affect the muscles and/or their nervous control. Ingeneral, problems with nervous control can cause either spasticity or some degree of 

 paralysis, depending on the location and the nature of the problem. A large proportion of 

neurological disorders leads to problems with movement. Some examples of thesedisorders include cerebrovascular accident (stroke), Parkinson's disease, multiple

sclerosis, myasthenia gravis, Huntington's disease (Huntington's chorea), and the

Creutzfeldt-Jakob disease.

Contents[hide]

• 1 Symptoms and testing

• 2 Causes, including autoimmune diseases and poisoning

• 3 Inflammatory muscle disorders

• 4 Tumors

• 5 See also

• 6 References

 [ edit  ] Symptoms and testing 

Symptoms of muscle disease may include muscular weakness, spasticity/rigidity, loss of 

muscular control, myoclonus (twitching, spasming), and myalgia (muscle pain).

Diagnostic procedures that may reveal muscular disorders include direct clinicalobservations (above all), the testing of various chemical and antigen levels in the blood,

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and electromyography (measuring electrical activity in muscles). Diagnostic imaging 

may be helpful in certain cases, such as those caused by strokes or tumors.

 [ edit  ] Causes, including autoimmune diseases and poisoning 

 Neuromuscular disease can be caused by circulatory problems (strokes, etc.),immunological and autoimmune disorders, the failure of the electrical insulation

surrounding nerves myelin, genetic/hereditary disorders, such as Huntington's disease,

certain rare tumors, the failure of the connections between the nerves and the musclefibers, exposure to pernicious environmental chemicals, poisoning - including heavy-

metal poisoning, and importantly, unknown causes. The failure of the electrical insulation

surrounding nerves, the myelin, is seen in certain deficiency diseases, such as the failureof the body's system for absorbing vitamin B-12, and also the failure of the myelin is seen

in multiple sclerosis and some other neurological diseases, especially in autoimmune 

diseases that are thought to attack the myelin.

Some neuromuscular diseases are hypothesized to be caused either by viral infections or  by attack by little-known pernicious proteins called  prions.

Diseases of the motor end plate include myasthenia gravis, a form of muscle weakness

due to antibodies to the acetylcholine receptor, and its related condition Lambert-Eaton

myasthenic syndrome (LEMS). Tetanus and botulism are bacterial infections in which bacterial toxins cause increased or decreased muscle tone, respectively.

The myopathies are all diseases affecting the muscle itself, rather than its nervous control

(??).

Muscular dystrophy is a large group of diseases, many of them hereditary or resultingfrom genetic errors, where the muscle integrity is disrupted. They lead to progressive lossof strength, high dependence and decreased life span.

 [ edit  ] Inflammatory muscle disorders

• Polymyalgia rheumatica (or "muscle rheumatism") is an inflammatory condition

that mainly occurs in the elderly; it is associated with giant-cell arteritis. It oftenresponds dramatically to glucocorticoids (e.g. prednisolone).

• Polymyositis, dermatomyositis and inclusion body myositis are autoimmune 

conditions in which the muscle is affected.

• Rhabdomyolysis is the breakdown of muscular tissue due to any cause. While itmay not lead to any muscular symptoms at all, the myoglobin thus released may

cause acute renal failure.

 [ edit  ] Tumors

Tumors of muscle are of the soft tissue sarcoma group and include:

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• Smooth muscle: leiomyoma (benign, very common in the uterus),

leiomyosarcoma (malignant, very rare)

• Striated muscle: rhabdomyoma (benign) and rhabdomyosarcoma (malignant) - both very rare

• Metastasis from elsewhere (e.g. lung cancer )

Smooth muscle has been implicated to play a role in a large number of diseases affecting

 blood vessels, the respiratory tract (e.g., asthma), the digestive system (e.g. irritable bowel syndrome) and the urinary tract (e.g., urinary incontinence). These disease

 processes are not usually confined to the muscular tissue. In general, muscle tumors are

rare, since muscle cells are not constantly dividing cells.

Tumors of the thymus gland are implicated in some cases of myasthenia gravis and other neuromuscular diseases.

Tumors of the peripheral nervous system are known, but rare, because nerve cells are not

ones that divide very much under normal circumstances.