Skeletal muscle.

muscles - one of the main components of the body.They are based on a fabric, fibers which contract under the influence of nerve impulses, which allows the body to move and be retained in the environment.

muscles are located in every part of our body.And even if we do not know of their existence, they are still there.Enough, for example, for the first time to go to the gym or aerobics - the next day you will start to hurt even those muscles, the presence of which you had no idea.

They are responsible not only for motion.At rest, the muscles also require energy to maintain a healthy body.This is necessary to ensure that at any point in a certain part of the body could respond to nerve impulses corresponding movement, rather than spending time on training.

To understand the structure of the muscles, we suggest to remember the basics, to repeat the classification and to look into the cellular structure of the muscles.We also learn about the diseases, which could affect their work, and how to strengthen the skeletal muscles.

General concepts

By its content and reactions occurring muscle fibers are divided into:

  • striated;
  • smooth.

Skeletal muscle - elongated tubular structures, the number of cores in a single cell that can reach up to several hundreds.They consist of muscle tissue, which is attached to various parts of the bony skeleton.Abbreviations striated muscles contribute to human movement.

Varieties forms

The different muscles?Photos presented in this article will help us figure it out.

Skeletal muscle is one of the main components of the musculoskeletal system.They allow you to move and to maintain balance, as well as involved in the process of respiration, phonation, and other functions.

In humans, there are over 60 muscles.The percentage of the total mass is 40% of total body weight.Muscles are classified according to form and structure:

  • thick spindle-shaped;
  • thin plate.

classification facilitates learning

division skeletal muscle groups is dependent on the location and value of their activities in the different organs of the body.The main groups:

muscles of the head and neck:

  • mimic - make you smile, communication and the creation of various grimaces while ensuring movement of the component parts of the face;
  • chewing - contribute to changing the situation of the maxillofacial department;
  • voluntary muscles of internal organs of the head (soft palate, tongue, eyes, middle ear).

Groups of skeletal muscles of the cervical:

  • surface - contribute oblique and rotational movements of the head;
  • average - create a bottom wall of the mouth and contribute to downward movement of the jaw, hyoid bone and laryngeal cartilage;
  • deep carry tilt and swivel head, creating lifting the first and second ribs.

Muscles photos you see here are responsible for the body and are divided into muscle bundles following departments:

  • chest - activates the upper torso and arms, and also contributes to a change in position of the ribs when breathing;
  • abdomen - gives the movement of blood through the veins, carries reposition the chest when breathing, affects the functioning of the gastrointestinal tract, promotes bending of the trunk;
  • back - creates a propulsion system of the upper extremities.

limb muscles:

  • top - are made up of muscle tissue of the shoulder girdle and upper limb free, helping to move the arm in the shoulder joint capsule and create a movement of the wrist and fingers;
  • lower - play a major role in the movement of man in space, divided into the muscles of the pelvic girdle and the free part.

structure of skeletal muscle

In its structure, it has a large number of muscle fibers elongated shape with a diameter of 10 to 100 microns, their length varies from 1 to 12 cm. The fibers (microfibrils) are thin - actin, and thick - myosin.

The first consists of a protein having a fibrillar structure.He called actin.Thick fibers consist of any type of myosin.They differ on the time required for decomposition of ATP molecules, which leads to different speed reductions.

Myosin in smooth muscle cells located in the dispersed state, although there is a large amount of protein, which in turn is in continuous mnogoznachaschim tonic contraction.

structure similar to skeletal muscle fibers woven rope or stranded wire.Top surrounds a thin cover of connective tissue, called epimizium.From its inner surface into finer muscle depart branching connective tissue creating partitions.They are "wrapped" individual bundles of muscle tissue, which contain up to 100 in each of the fibrils.They are deeper depart narrower branches.

through all layers in the skeletal muscles penetrate the circulatory and nervous systems.Arterial Vienna runs along perimiziuma - a connective tissue that covers the bundles of muscle fibers.Arterial and venous capillaries are located nearby.

development process

Skeletal muscles develop from mesoderm.From the nervous groove formed somites.When the time them are myotomes.Their cells, taking the form of a spindle, evolving into myoblasts, which are divided.Some of them are progressing, while others remain unchanged and form miosatellitotsity.

minor part of myoblasts due to contact of the pole makes contact with each other, then in the contact zone of the plasma membrane break.The merger cells are symplasts.They are moving muscular young undifferentiated cells found in a single environment with myosymplast basement membrane.

skeletal muscle function

muscles This is the basis of the musculoskeletal system.If it is strong, the body is easier to maintain in position, and the probability of occurrence of scoliosis stoop or minimized.On the pros know all sports, so we consider the role played by the muscles.

contractile skeletal muscle tissue in the human body performs a variety of functions, which are necessary for correct positioning of the body and its parts interact with each other.

muscles perform the following functions:

  • creates mobility of the body;
  • cherish heat energy created within the body;
  • facilitate transport and vertical retention in space;
  • contribute to the reduction of the respiratory tract and help with swallowing;
  • form facial expressions;
  • contribute to the development of heat.

Ongoing support

When the muscle is at rest, there is always a slight tension, called muscle tone.It is formed due to minor pulsed frequencies that arrive to the muscles from the spinal cord.Their effect is caused by signals that penetrate from the head to the spinal motor neurons.Muscle tone is also dependent on their overall:

  • stretching;
  • filling level of muscle sheaths;
  • enrich the blood;
  • total water and salt balance.

Man has the ability to adjust the load of the muscles.As a result of prolonged exercise or strong emotional and nervous overstrain involuntary muscle tone increases.

Abbreviations skeletal muscles and their varieties

This function is fundamental.But even she, with apparent simplicity, can be divided into several types.

Types of contractile muscle:

  • isotonic - the ability of muscle tissue intact shortened muscle fibers;
  • isometric - the reaction of the fiber is reduced, but its length remains the same;
  • auksotonicheskie - the process of contraction of the muscle tissue, where the length and tension of the muscles subjected to changes.

consider this process in more detail

first brain sends through the neuronal impulses that comes to motor neuron adjacent to muscle bundles.Next it is innervated by efferent neurons of synoptic vesicle and released neurotransmitter.It binds to receptors on the sarcolemma of muscle fibers and opens the sodium channel, which leads to membrane depolarization, causing an action potential.With sufficient neurotransmitter, stimulates production of calcium ions.Then it connects to troponin and promotes its reduction.That, in turn, pulls tropomeazin, allowing to connect actin and myosin.

Then begins the process of sliding actin filament with respect to myosin, whereby there is a reduction of skeletal muscle.To understand the process of contraction of striated muscle bundles will schematic representation.

The principle of skeletal muscle

interaction large number of muscle bundles helps the various movements of the body.

work of skeletal muscles can occur in such ways:

  • synergist muscles work in the same direction;
  • antagonist muscles contribute to the implementation of opposing motions for voltage.

antagonistic action of muscles is one of the main factors in the activity of the musculoskeletal system.In carrying out any action in the work included not only the muscle fibers that make it, and their antagonists.They help to counter the movement and give concreteness and grace.

striated muscle when subjected to the joint makes a difficult job.Her character is determined by the location of the axis of the joint and the relative position of the muscle.

Some functions of skeletal muscles are underreported, and often do not talk about them.For example, some of the beams protrude lever for bones.

work muscles at the cellular level

action of skeletal muscles at the expense of two proteins: actin and myosin.These components are able to move relative to each other.To

performance muscle tissue requires energy expenditure contained in the chemical bonds of organic compounds.The decomposition and oxidation of substances occur in the muscles.There is always present the air and releases energy, 33% of the total spent on the performance of the muscle tissue and 67% transferred to other tissues and is spent on the maintenance of a constant body temperature.

skeletal muscle diseases

In most cases, abnormalities in the functioning of muscles caused by medical condition of the nervous system responsible.

most common pathology of skeletal muscle:

  • Muscle cramps - electrolyte imbalance in the extracellular fluid surrounding muscle and nerve fibers, as well as changes in osmotic pressure in it, especially the increase.
  • hypocalcemic tetany - involuntary tetanic contraction of skeletal muscles, the observed drop in extracellular Ca2 + concentration up to about 40% of normal levels.
  • Muscular dystrophy is characterized by progressive degeneration of skeletal muscle fibers and infarction, as well as muscular disability that can result in death due to respiratory or cardiac failure.
  • Myasthenia gravis - a chronic autoimmune disease in which the body produce antibodies to nicotine ACh-receptor.

relaxation and regeneration of skeletal muscle

Proper nutrition, lifestyle and regular exercise will help you become an owner of beautiful and healthy skeletal muscles.Optionally, engage in weight training and build muscle mass.Enough of regular cardio and yoga.

Do not forget the compulsory acceptance of essential vitamins and minerals, as well as regular visits to saunas and baths with brooms, which allow oxygen to enrich muscle tissue and blood vessels.

Systematic relaxing massages will improve flexibility and reproducibility of muscle bundles.It is also a positive impact on the structure and function of skeletal muscle has cryosauna visit.