MUSCLE TISSUE

Muscle tissue is responsible for body movements. It consists of elongated cells, muscle fibers, characterized by the presence of large numbers of specific cytoplasmic filaments.

Muscle cells have mesodermal origin and their differentiation occurs primarily in a gradual lengthening process are simultaneous synthesis of filamentous proteins.

According to their morphological and functional characteristics can be differentiated into three types of mammalian muscle, smooth muscle, skeletal and cardiac striated.

This tissue of mesenchymal origin, is constituted

• muscle cells (muscle fibers) capable of generating movements under appropriate stimulus by contracting and then relaxing and
• tissue closely associated with muscle cells. This acts as a mooring system and traction coupling of muscle cells so that they can act together. It also leads the blood
  vessels and innervation of muscle fibers itself

In vertebrates, three types are distinguished muscle:

• skeletal , striated or voluntary
• heart , striated involuntary
• smooth , involuntary

Each type of muscle cell structure is different, tailored to their specific function, but in all cases the intracellular contractile machinery consists of filaments that are oriented parallel to the direction of motion. All varieties of muscle cells harness the chemical energy stored in ATP and transformed into mechanical energy.

Diagnostic

a group of inherited disorders characterized by weakness and atrophy of muscle tissue, with or without degeneration of nerve tissue. There are nine types of muscular dystrophy and they all occur with the eventual loss of strength, increasing disability and sometimes deformity.

The best known of the muscular dystrophies is Duchenne muscular dystrophy (DMD English acronym), followed by Becker muscular dystrophy (BMD its acronym in English).

Here are nine different types of muscular dystrophy. Each type differs in the affected muscles, the age of onset and rate of progression. Some types are named after the affected muscles, including the following:

Age of onset type symptoms, progression rate and average life

Becker

Adolescence to early adulthood Symptoms are almost identical to Duchenne but less severe, progresses more slowly than Duchenne; survival into middle age. congenital

At birth Symptoms include general muscle weakness and possible joint deformities; the disease progresses slowly; short life.

Duchenne

Between 2 and 6 years Symptoms include general weakness and wasting of muscles, affecting the pelvis, upper arms and legs and eventually involves all voluntary muscles, survival beyond age 20 is slightly frequent. distal

Between 40 and 60 Symptoms include weakness and wasting of the muscles of the hands, forearms and lower legs, the progression is slow, rarely leads to total disability.

Emery-Dreifuss

Between childhood and puberty Symptoms include weakness and wasting of the muscles of the shoulders, upper arm and shin, are common joint deformities, the progression is slow, can cause sudden death from cardiac problems.

facioscapulohumeral

From childhood to early adults Symptoms include facial muscle weakness and deformity and degree of atrophy of the shoulder and upper arm, the progression is slow, with periods of rapid deterioration, the patient may live for several decades after of its appearance.

Girdle

Between late childhood and middle age Symptoms include weakness and wasting, affecting first the shoulder girdle (shoulder) and pelvic progression is slow, death is usually due to cardiopulmonary complications.

 

myotonic

Between 20 and 40 Symptoms include weakness of all muscle groups accompanied by delayed relaxation of muscles after contraction, affecting first the face, feet, hands and neck, the progression is slow; sometimes spanning 50 to 60 years.

oculopharyngeal

Between 40 and 70 Symptoms affect muscles of eyelids and throat causing weakening of throat muscles that, over time, causes inability to swallow and emaciation from lack of food, the progression is slow.

 

MUSCULAR SYSTEM

The system allows the skeletal muscle to move, it is stable and shape of the body. In vertebrates is controlled through the nervous system, although some muscles (such as the heart) can operate autonomously. Approximately 40% of the human body consists of muscles, namely that for every kg of total weight, 400 g corresponding to muscle tissue.

Muscular system is formed by the set of skeletal muscles, whose mission is the movement of body. Along with the bones is the musculoskeletal system, which is the active part, as the muscles are responsible for the movements of the bones.

Skeletal muscles contract in response to nerve impulses. These impulses travel through ner-motor nerves that terminate in the muscles. The contact area between a rib and a striated muscle fiber skeletal neuromuscular junction is known as motor or plate.

The human body has over 600 muscles. These muscles are attached directly or indirectly (through tendons) to bone and generally work in antagonistic pairs when one contracts the other relaxes

 

MUSCULAR SYSTEM FUNCTIONS

The main functions of the muscular system are: Body movement (locomotion) or any of its parts. Heat production. The muscles produce 40% of body heat at rest and up to 80% during the exercise.

Maintaining the posture.

Mimicry: a share of certain muscles, especially of the face, you can take certain gestures

used to
express feelings

 

Depending on the type of movement they make, one can distinguish the following types of
muscles:

Flexors and extensors: closer or apart, respectively, two parts of a member.

The application of these terms in relation to the hip and shoulder requires a special definition. The flexion in these structures is a movement by which the thigh and arm are moved front, by extension, thigh and arm move back.

Abductors and adductors: away or moving parts come to a central axis.

Rotator: a bone rotated around a longitudinal axis. Pronation and supination are two special forms of rotation.

Pronation is the joint rotation of the forearm and hand, leaving the palms facing backwards. Supination is the opposite movement.

Elevators or depressants: raise or lower a body part.

Sphincters and dilators: make or break a body orifice

 

MUSCULAR SYSTEM COMPONENTS

The muscular system consists of muscles and tendons. The main function of muscles is contract, to generate movement and perform vital functions.

 

TYPES OF MUSCLES

A) As we are available with three types of muscles:

• Skeletal muscle and striated

• The smooth muscle or viscera l

• The heart muscle

B) Depending on how they are controlled:

• Volunteers: controlled by the individual (skeletal muscles: quadriceps, pectoral)

• Involuntary or visceral: led by the central nervous system (intestines, esophagus.)

• Standalone: ​​its function is to contract smoothly without stopping (heart)

• Mixed: controlled by the individual muscles and nervous system, such as eyelids.

 

MUSCLE ATROPHY

Muscle atrophy is the wasting or loss of muscle tissue.

There are two types of muscle atrophy.

• Disuse atrophy occurs from a lack of physical activity. In most people, muscle atrophy is caused by not using the muscles enough. People with seated jobs, medical conditions that limit their movement, or decreased activity levels can lose muscle tone and develop atrophy. This type of atrophy can be reversed with exercise and better nutrition. Bedridden people can have significant muscle wasting. Astronauts who are away from the Earth's gravity can develop decreased muscle tone after just a few days of weightlessness.
• The most severe type of muscle atrophy is neurogenic atrophy. It occurs when there is an injury to, or disease of, a nerve that connects to the muscle. This type of muscle atrophy tends to occur more suddenly than disuse atrophy.

Examples of diseases affecting the nerves that control muscles:

• Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease)
• Guillain-Barre syndrome
  
• Neuropathy
• Polio (poliomyelitis)

Some muscle atrophy occurs normally with aging. Other causes may include:

• Alcohol-associated myopathy
• Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease)
• Burns
  
• Dermatomyositis and polymyositis
  
• Guillain-Barre syndrome
• Injury
• Long-term corticosteroid therapy
• Malnutrition
  
• Motor neuropathy (such as diabetic neuropathy)
• Muscular dystrophy
  
• Not moving (immobilization)
• Osteoarthritis
  
• Polio
  
  
• Rheumatoid arthritis  
• Spinal cord injury
  
• Stroke
  

Neuromuscular Disorders

 Neuromuscular disorders affect the nerves that control your voluntary muscles. Voluntary muscles are the ones you can control, like in your arms and legs. Your nerve cells, also called neurons, send the messages that control these muscles. When the neurons become unhealthy or die, communication between your nervous system and muscles breaks down. As a result, your muscles weaken and waste away. The weakness can lead to twitching, cramps, aches and pains, and joint and movement problems. Sometimes it also affects heart function and your ability to breathe.

Examples of neuromuscular disorders include

• Amyotrophic lateral sclerosis
  
• Multiple sclerosis
  
• Muscular dystrophy
  
• Myasthenia gravis
  
• Spinal muscular atrophy
  

Many neuromuscular diseases are genetic, which means they run in families or there is a mutation in your genes. Sometimes, an immune system disorder can cause them. Most of them have no cure. The goal of treatment is to improve symptoms, increase mobility and lengthen life.

 

BOTULISM:

Botulism is a rare but serious illness caused by Clostridium botulinum bacteria. The bacteria may enter the body through wounds, or they may live in improperly canned or preserved food.

Causes, incidence, and risk factors

Clostridium botulinum is found in soil and untreated water throughout the world. It produces spores that survive in improperly preserved or canned food, where they produce toxin. When eaten, even tiny amounts of this toxin can lead to severe poisoning.

The foods most commonly contaminated are home-canned vegetables, cured pork and ham, smoked or raw fish, and honey or corn syrup. Botulism may also occur if the bacteria enter open wounds and produce toxins there.

Infant botulism occurs when a baby eats living bacteria or its spores and they grow in the baby's gastrointestinal tract. The most common cause of infant botulism is eating honey or corn syrup.

Clostridium botulinum also occurs normally in the stool of some infants.

About 110 cases of botulism occur in the U.S. per year. Most of the cases are in infants.

Symptoms

Symptoms usually appear 8 - 36 hours after you eat contaminated food. There is NO fever with this infection.

In adults, symptoms may include:

• Abdominal cramps
• Breathing difficulty that may lead to respiratory failure
• Difficulty swallowing and speaking
• Double vision
  
• Dry mouth
• Nausea
• Vomiting
• Weakness with paralysis (equal on both sides of the body)

Symptoms in infants may include:

• Constipation
• Poor feeding and weak sucking
• Respiratory distress
• Weak cry
• Weakness, loss of muscle tone

Signs and tests

The health care provider will perform a physical exam. There may be signs of:

• Absent or decreased deep tendon reflexes
• Absent or decreased gag reflex
• Eyelid drooping
  
• Loss of muscle function/feeling
• Paralyzed bowel
• Speech impairment
• Urine retention with inability to urinate

Blood tests can be done to identify the toxin. A stool culture may also be ordered. Lab tests can be done on the suspected food to confirm botulism.

Treatment

You will get botulinus antitoxin.

For breathing trouble, you will have to stay in a hospital. The health care team will clear your airway and provide treatment. A tube may be inserted through the nose or mouth into the windpipe to provide an airway for oxygen. You may need a breathing machine.

Patients who have trouble swallowing may getintravenous fluids. A feeding tube may be inserted.

Health care providers report cases of botulism to state health authorities or the U.S. Centers for Disease Control and Prevention so that the contaminated food can be removed from stores.

Some people receive antibiotics, but they may not always help.

TETANUS:

Tetanus is infection of the nervous system with the potentially deadly bacteria Clostridium tetani

 

Spores of the bacteria C. tetani live in the soil and are found around the world. In the spore form, C. tetani may remain inactive in the soil, but it can remain infectious for more than 40 years.

Infection begins when the spores enter the body through an injury or wound. The spores release bacteria that spread and make a poison called tetanospasmin. This poison blocks nerve signals from the spinal cord to the muscles, causing severe muscle spasms. The spasms can be so powerful that they tear the muscles or cause fractures of the spine.

The time between infection and the first sign of symptoms is typically 7 to 21 days. Most cases of tetanus in the United States occur in those who have not been properly vaccinated against the disease.

Symptoms

Tetanus often begins with mild spasms in the jaw muscles (lockjaw). The spasms can also affect the chest, neck, back, and abdominal muscles. Back muscle spasms often cause arching, called opisthotonos.

Sometimes the spasms affect muscles that help with breathing, which can lead to breathing problems.

Prolonged muscular action causes sudden, powerful, and painful contractions of muscle groups. This is called tetany. These episodes can cause fractures and muscle tears.

Other symptoms include:

• Drooling
  
  
• Excessive sweating
• Fever
  
• Hand or foot spasms
  
• Irritability
• Swallowing difficulty
• Uncontrolled urination or defecation

Treatment

Treatment may include:

• Antibiotics, including penicillin, clindamycin, erythromycin, or metronidazole (metronidazole has been most successful)
• Bedrest with a nonstimulating environment (dim light, reduced noise, and stable temperature)
• Medicine to reverse the poison (tetanus immune globulin)
• Muscle relaxers such as diazepam
  
• Sedatives
• Surgery to clean the wound and remove the source of the poison (debridement)

Breathing support with oxygen, a breathing tube, and a breathing machine may be necessary.

Muscular dystrophy

Muscular dystrophy is a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time.

Causes, incidence, and risk factors

Muscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. There are many different types of muscular dystrophy. They include:

• Becker muscular dystrophy
  
• Duchenne muscular dystrophy
  
• Emery-Dreifuss muscular dystrophy
  
  
• Facioscapulohumeral muscular dystrophy
  
• Limb-girdle muscular dystrophy
• Myotonia congenita
  
• Myotonic dystrophy

Symptoms

Symptoms vary with the different types of muscular dystrophy.

All of the muscles may be affected. Or, only specific groups of muscles may be affected, such as those around the pelvis, shoulder, or face. Muscular dystrophy can affect adults, but the more severe forms tend to occur in early childhood.

Symptoms include:

• Mental retardation (only present in some types of the condition)
• Muscle weakness that slowly gets worse
  • Delayed development of muscle motor skills
  • Difficulty using one or more muscle groups
  • Drooling
    
  • Eyelid drooping (ptosis)
  • Frequent falls
  • Loss of strength in a muscle or group of muscles as an adult
  • Loss in muscle size
  • Problems walking (delayed walking)

Treatment

There are no known cures for the various muscular dystrophies. The goal of treatment is to control symptoms.

Physical therapy may help patients maintain muscle strength and function. Orthopedic appliances such as braces and wheelchairs can improve mobility and self-care abilities. In some cases, surgery on the spine or legs may help improve function.

Corticosteroids taken by mouth are sometimes prescribed to children to keep them walking for as long as possible.

The person should be as active as possible. Complete inactivity (such as bedrest) can make the disease worse