The structure of human muscles. Human muscle anatomy

Now let's talk about the structure of our muscles.

Human muscles are a popular topic for any athlete. Therefore, I think the following material will not make big discoveries for you, because... Most athletes have at least a minimal amount of knowledge about the structure of their muscles, but still...

If you have firmly decided to do something, then, first of all, you need to clearly understand what specific steps can lead you to your goal.

Agree, the desire to increase, for example, the size of your arms is not enough. You need, at a minimum, to know what exactly to “download” for this purpose, i.e. which specific muscles need to be worked to achieve specific goals. And drawing up training programs, specific exercises, nutrition - these are the next steps. Therefore, human muscles are one of the topics with which the difficult path of an athlete should begin.

The location of human muscles is clearly shown in the figures, and their description is given below:

Until you understand the structure of your own body, you will not fully understand the meaning of your actions during training.

There is a lot of information about skeletal muscles; I believe that human muscles are most clearly and rationally described in the book “” (authors: Arnold Schwarzenegger with the participation of Bill Dobbins).

So, our body consists of more than six hundred muscles. Of course, you don’t need a detailed study; the following classification of the main muscle groups will suffice:

1. Back: latissimus (lateral) muscle, rhomboid muscle, infraspinatus muscle, teres major muscle, spinal extensor muscles;
2. Shoulder girdle: deltoid muscle (consists of anterior, middle and posterior heads), brachialis muscle, coracobrachialis muscle, trapezius muscle;
3. Rib cage: pectoralis major (pectoral) muscle (consists of upper and lower sections), serratus pectoralis muscle, intercostal muscles;
4. Biceps and triceps: biceps (its upper and lower parts), triceps (its three heads);
5. Forearms(arm muscles from the elbow to the hand): flexor muscles of the forearm, extensor muscles of the wrist, brachioradialis muscle;
6. Hips and buttocks: quadriceps (middle, external, internal heads), gracilis, adductor magnus, sartorius, adductor longus, tensor fasciae lata, pectineus, hamstrings (biceps femoris, semimembranosus, semitendinosus) , iliopsoas muscle, gluteal muscles (medius and gluteus maximus muscles);
7. Stomach: rectus abdominis, external obliques;
8. Shin: tibialis anterior muscle, gastrocnemius muscle (its external and internal heads), soleus muscle.

After you have become familiar with the general structure of human muscles, the most rational step would be to study the section, which contains unique information about the work of muscles, the principles of their contraction, energy, etc.

Believe me, without this knowledge you will never understand how your muscles work and what makes them contract and grow!

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Back muscles

13. Latissimus muscle. Located on the back of the chest. Brings the shoulder toward the body, rotates the arm inward, and pulls it back.

14. Long muscles. Located along the spine. Unbend, tilt and rotate the torso to the sides.

The back muscles also include the trapezius muscle, which was discussed above.

Leg muscles

15. Gluteal muscles. Move the leg in the hip joint, abduct, extend, rotate the thigh in and out. Straighten the torso bent forward.

16. Quadriceps muscle. Located on the front of the thigh. She extends the leg at the knee, flexes the thigh at the hip joint and rotates it.

17. Biceps muscle. Located on the back of the thigh. Bends the leg at the knee joint and extends it at the hip joint.

18. Calf muscle. Located on the back of the lower leg. Flexes the foot, participates in flexion of the leg at the knee joint.

19. Soleus muscle. Located deep in the lower leg. Flexes the foot.

2.3.2. Cordially- vascular system(circulatory system). The activity of all systems of the human body is carried out through the interaction of humoral (fluid) regulation and the nervous system. Humoral regulation is carried out by an internal transport system through the blood and circulatory system, which includes the heart, blood vessels, lymphatic vessels and organs that produce special cells - formed elements.

The movement of blood and lymph through the vessels occurs continuously, due to which organs, tissues, and cells constantly receive the nutrients and oxygen they need during the assimilation process, and decay products are continuously removed during the metabolic process

Depending on the the nature and composition of the fluid circulating in the body vascular system divided into circulatory and lymphatic.

Blood- this is a type of connective tissue with liquid intercellular substance (plasma) - 55% and formed elements suspended in it (erythrocytes, leukocytes and platelets) - 45%. The main components of plasma are water (90-92%), the rest are proteins and minerals. Due to the presence of proteins in the blood, its viscosity is higher than water (about 6 times). The composition of the blood is relatively stable and has a weak alkaline reaction.

Red blood cells- red blood cells, they are the carrier of the red pigment - hemoglobin. Hemoglobin is unique in that it has the ability to form substances in combination with oxygen. Hemoglobin makes up almost 90% of red blood cells and serves as a carrier of oxygen from the lungs to all tissues. In 1 cubic mm of blood in men on average 5 million red blood cells, in women - 4.5 million. In people involved in sports, this value reaches 6 million or more. Red blood cells are produced in red bone marrow cells.

Leukocytes- white blood cells. They are not nearly as numerous as red blood cells. In 1 cubic mm of blood contains 6-8 thousand white blood cells. The main function of leukocytes is to protect the body from pathogens. A feature of leukocytes is the ability to penetrate to places where microbes accumulate from capillaries into the intercellular space, where they perform their protective functions. Their lifespan is 2-4 days. Their number is constantly replenished due to newly formed cells from the bone marrow, spleen and lymph nodes.

Platelets- blood platelets, the main function of which is to ensure blood clotting. Blood clots due to the destruction of platelets and the conversion of soluble plasma protein fibrinogen into insoluble fibrin. Protein fibers together with blood cells form clots that clog the lumens of blood vessels.

Under the influence of systematic training, the number of red blood cells and the hemoglobin content in the blood increase, resulting in an increase in the oxygen capacity of the blood. The body's resistance to colds and infectious diseases increases due to increased activity of leukocytes.

Basic functions of blood:

- transport - delivers nutrients and oxygen to cells, removes metabolic breakdown products from the body;

- protective - protects the body from harmful substances and infections, due to the presence of a coagulation mechanism, stops bleeding;

- heat exchange - participates in maintaining a constant body temperature.

Blood in the human body moves through a closed system, in which there are two circles of blood circulation - large and small. The human blood circulation diagram contains 10 elements: 1 – right atrium; 2 – right ventricle; 3 – pulmonary artery; 4 - capillaries in the lungs; 5 – pulmonary vein; 6 – left atrium; 7 – left ventricle; 8 – aorta; 9 – capillaries of the body; 10 – vena cava.

The center of the circulatory system is the heart, which acts as two pumps. The right side of the heart (venous) moves blood through the pulmonary circulation, the left (arterial) - through the systemic circulation.

The pulmonary circulation begins from the right ventricle of the heart, then venous blood enters the pulmonary trunk, which is divided into two pulmonary arteries, which are divided into smaller arteries that pass into the capillaries of the alveoli, in which gas exchange occurs (the blood gives off carbon dioxide and is enriched with oxygen).

Two veins emerge from each lung and drain into the left atrium. The systemic circulation begins from the left ventricle of the heart. Arterial blood enriched with oxygen and nutrients flows to all organs and tissues where gas exchange and metabolism occur. Having taken carbon dioxide and decay products from the tissues, venous blood collects in the veins and moves to the right atrium.

Blood moves through the circulatory system, which is arterial (saturated with oxygen) and venous (saturated with carbon dioxide).

A person has three types of blood vessels: arteries, veins, capillaries. Arteries and veins differ from each other in the direction of blood movement in them. Thus, an artery is any vessel that carries blood from the heart to an organ, and a vein is a vessel that carries blood from an organ to the heart, regardless of the composition of the blood (arterial or venous) in them.

Capillaries- the thinnest vessels, they are 15 times thinner than a human hair. The walls of the capillaries are semi-permeable, through which substances dissolved in the blood plasma leak into the tissue fluid, from which they pass into the cells. Products of cell metabolism penetrate in the opposite direction from tissue fluid into the blood.

Blood moves through the vessels from the heart under the influence of pressure created by the heart muscle at the time of its contraction. The return movement of blood through the veins is influenced by several factors:

Firstly, venous blood moves towards the heart under the action of contractions of skeletal muscles, which seem to push blood out of the veins towards the heart, while the reverse movement of blood is excluded, since the valves located in the veins allow blood to pass in only one direction - to the heart .

The mechanism of forced movement of venous blood to the heart overcoming the forces of gravity under the influence of rhythmic contractions and relaxations of skeletal muscles is called a muscle pump.

Thus, firstly, skeletal muscles during cyclic movements significantly help the heart to ensure blood circulation in the vascular system;

Secondly, when inhaling, the chest expands and a reduced pressure is created in it, which ensures the suction of venous blood to the thoracic region;

Thirdly, at the moment of systole (contraction) of the heart muscle, when the atria relax, a suction effect also occurs in them, promoting the movement of venous blood to the heart.

Heart- the central organ of the circulatory system. The heart is a hollow four-chambered muscular organ located in the thoracic cavity, divided by a vertical septum into two halves - left and right, each of which consists of a ventricle and an atrium. The heart works automatically under the control of the central nervous system.

The wave of oscillations propagated along the elastic walls of the arteries as a result of the hydrodynamic shock of a portion of blood ejected into the aorta during contraction of the left ventricle is called the heart rate (HR).

The heart rate of an adult man at rest is 65-75 beats/min, in women it is 8-10 beats more than in men. In trained athletes, the heart rate at rest becomes lower due to an increase in the power of each heartbeat and can reach 40-50 beats/min.

The amount of blood pushed out by the ventricle of the heart into vascular bed during one contraction, is called the systolic (stroke) volume of blood. At rest, it is 60 ml for untrained people, and 80 ml for trained people. During physical activity, it increases to 100-130 ml for untrained people, and to 180-200 ml for trained people.

The amount of blood ejected by one ventricle of the heart within one minute is called the minute volume of blood. At rest, this figure is on average 4-6 liters. During physical activity, it increases in untrained people to 18-20 liters, and in trained ones up to 30-40 liters.

With each contraction of the heart, the blood entering the circulatory system creates pressure in it, depending on the elasticity of the walls of the blood vessels. Its value at the moment of heart contraction (systole) is 115-125 mm Hg in young people. Art. The minimum (diastolic) pressure at the moment of relaxation of the heart muscle is 60-80 mm Hg. Art.

The difference between the maximum and minimum pressure is called pulse pressure. It is approximately 30-50 mm Hg. Art.

Under the influence of physical training, the size and weight of the heart increase due to the thickening of the walls of the heart muscle and an increase in its volume. The muscle of a trained heart is more densely penetrated with blood vessels, which ensures better nutrition of the muscle tissue and its performance.

2.3.3. Breath. Respiratory system. Respiration is a complex of physiological processes that ensure the consumption of oxygen and the release of carbon dioxide by a living organism. The breathing process is usually divided into:

- external(pulmonary), i.e. exchange of gases between the lungs and the atmosphere;

- fabric, those. the process of exchanging oxygen and carbon dioxide between the blood and body cells.

External breathing carried out using a breathing apparatus consisting of airways (nasal cavity, nasopharynx, larynx, windpipe, trachea and bronchi). The walls of the nasal passage are covered with ciliated epithelium, which traps dust incoming air. The air inside the nasal passage is warmed. When breathing through the mouth, air enters directly into the pharynx and from it into the larynx, without being cleaned or warmed.

When you inhale, air enters the lungs, each of which is located in the pleural cavity and works in isolation from each other. Each lung is shaped like a cone. On the side facing the heart, a bronchus enters each lung (the hilum of the lung), dividing into smaller bronchi to form the so-called bronchial tree. Small bronchi end in alveoli, which are intertwined with a dense network of capillaries through which blood flows. As blood passes through the pulmonary capillaries, gas exchange occurs: carbon dioxide, released from the blood, enters the alveoli, which release oxygen into the blood.

Indicators of the performance of the respiratory organs are tidal volume, respiratory rate, vital capacity, pulmonary ventilation, oxygen consumption, etc.

Tidal volume- the volume of air passing through the lungs in one respiratory cycle (inhalation, exhalation). This figure increases significantly in trained people and ranges from 800 ml or more. In untrained people, the tidal volume at rest is at the level of 350-500 ml.

If, after a normal exhalation, you make a maximum exhalation, then another 1.0-1.5 liters of air will come out of the lungs. This volume is usually called reserve. The amount of air that can be inhaled beyond the tidal volume is called supplemental volume. The sum of three volumes: respiratory, additional and reserve is the vital capacity of the lungs.

Vital capacity of the lungs(VC) - the maximum volume of air that a person can exhale after a maximum inhalation (measured by spirometry).

The vital capacity of the lungs largely depends on age, gender, height, chest circumference, and physical development. In men, vital capacity ranges from 3200-4200 ml, in women 2500-3500 ml. In athletes, especially those involved in cyclic sports (swimming, cross-country skiing, etc.), vital capacity can reach 7000 ml or more in men, 5000 ml or more in women.

Breathing rate- number of respiratory cycles per minute. One cycle consists of inhalation, exhalation and a breathing pause. The average resting respiratory rate is 15-18 cycles per minute. In trained people, due to an increase in tidal volume, the respiratory rate decreases to 8-12 cycles per minute. During physical activity, the respiratory rate increases, for example, in swimmers up to 45 cycles per minute.

Pulmonary ventilation- the volume of air that passes through the lungs in a minute. The amount of pulmonary ventilation is determined by multiplying the tidal volume by the respiratory rate. Pulmonary ventilation at rest is at the level of 5000-9000 ml. With physical activity this figure increases.

Oxygen consumption- the amount of oxygen used by the body at rest or during exercise in 1 minute.

At rest, a person consumes 250-300 ml of oxygen per minute. With physical activity this value increases.

The greatest amount of oxygen that the body can consume per minute during maximum muscular work is called maximum oxygen consumption (MOC).

The respiratory system is most effectively developed by cyclic sports (running, rowing, swimming, skiing, etc.).

2.3.4. Nervous system. The human nervous system unites all body systems into a single whole and consists of several billion nerve cells and their processes. Long processes of nerve cells unite to form nerve fibers that connect to all human tissues and organs.

The nervous system is divided into central and peripheral. The central nervous system includes the brain and spinal cord. The peripheral nervous system is formed by nerves that arise from the brain and spinal cord. There are 12 pairs of cranial nerves from the brain, and 31 pairs of spinal nerves from the spinal cord.

According to the functional principle, the nervous system is divided into somatic and autonomic. Somatic nerves innervate the striated muscles of the skeleton and some organs (tongue, pharynx, larynx, etc.). Autonomic nerves regulate the functioning of internal organs (heart contraction, intestinal peristalsis, etc.).

The main nervous processes are excitation and inhibition that occur in nerve cells. Excitation is the state of nerve cells when they transmit or direct nerve impulses themselves to other cells. Inhibition is a state of nerve cells when their activity is aimed at restoration.

The nervous system operates on the principle of a reflex. There are two types of reflexes: unconditioned (innate) and conditioned (acquired in the process of life).

Reflex- this is the body’s response to irritation, carried out with the participation of the central nervous system.

All human movements represent new forms of motor acts acquired in the process of individual life.

Motor skill- a motor action performed automatically without the participation of attention and thinking.

The formation of a motor skill occurs sequentially in three phases: generalization, concentration, automation.

The generalization phase is characterized by expansion and intensification of the excitatory process, as a result of which additional muscle groups are included in the work. In this phase, movements are uneconomical, poorly coordinated and imprecise.

The concentration phase is characterized by differentiated inhibition of excessive excitation and its concentration in the desired areas of the brain. Movements in this phase become precise, economical, and stable.

The automation phase is characterized by the execution of movements automatically, without the participation of attention and thinking. An automated skill is characterized by a high degree of reliability and stability in the execution of all its component movements.

Various analyzers are involved in the formation of a motor skill: motor, vestibular, cutaneous, etc.

Analyzer- this is the structural integrity of the receptor and nerve that conducts excitation to the center located in the cerebral cortex. Changing the function of a particular analyzer is closely related to the specifics of physical exercise. Those who engage in physical exercise improve their oculomotor analyzer, increase their field of vision (the norm is 15°, with special training up to 30°) and improve their depth of perception. When studying the skin analyzer during training, it was found that those areas of the body that are exposed to contact and shock have reduced tactile and pain sensitivity.

In the process of physical training, the human nervous system improves, carrying out a more subtle interaction between the processes of excitation and inhibition of various nerve centers. Training allows the sense organs to carry out motor actions in a more differentiated manner and forms the ability to more quickly master new motor skills.

The anatomy of human muscles, their structure and development, perhaps, can be called the most pressing topic that arouses maximum public interest in bodybuilding. Needless to say, the structure, work and function of muscles is a topic that a personal trainer should pay special attention to. As in the presentation of other topics, we will begin the introduction to the course with a detailed study of the anatomy of muscles, their structure, classification, work and functions.

Maintaining a healthy lifestyle, proper nutrition and systematic physical activity help develop muscles and reduce body fat levels. The structure and work of human muscles will be understood only by sequentially studying first the human skeleton and only then the muscles. And now that we know from the article that it also functions as a frame for attaching muscles, it’s time to study what main muscle groups form the human body, where they are located, what they look like and what functions they perform.

Above you can see what the human muscle structure looks like in the photo (3D model). First, let's look at the musculature of a man's body with terms applied to bodybuilding, then the musculature of a woman's body. Looking ahead, it is worth noting that the muscle structure of men and women is not fundamentally different; the musculature of the body is almost completely similar.

Human muscle anatomy

Muscles are called organs of the body that are formed by elastic tissue, and the activity of which is regulated by nerve impulses. The functions of muscles include movement and movement in space of parts of the human body. Their full functioning directly affects the physiological activity of many processes in the body. Muscle function is regulated by the nervous system. It promotes their interaction with the brain and spinal cord, and also participates in the process of converting chemical energy into mechanical energy. The human body forms about 640 muscles (various methods of counting differentiated muscle groups determine their number from 639 to 850). Below is the structure of human muscles (diagram) using the example of a male and female body.

Muscle structure of a man, front view: 1 – trapezoid; 2 – serratus anterior muscle; 3 – external oblique abdominal muscles; 4 – rectus abdominis muscle; 5 – sartorius muscle; 6 – pectineus muscle; 7 – long adductor muscle of the thigh; 8 – thin muscle; 9 – tensor fascia lata; 10 – pectoralis major muscle; 11 – pectoralis minor muscle; 12 – anterior head of the humerus; 13 – middle head of the humerus; 14 – brachialis; 15 – pronator; 16 – long head of the biceps; 17 – short head of the biceps; 18 – palmaris longus muscle; 19 – extensor muscle of the wrist; 20 – adductor carpi longus muscle; 21 – long flexor; 22 – flexor carpi radialis; 23 – brachioradialis muscle; 24 – lateral thigh muscle; 25 – medial thigh muscle; 26 – rectus femoris muscle; 27 – long peroneal muscle; 28 – extensor digitorum longus; 29 – tibialis anterior muscle; 30 – soleus muscle; 31 – calf muscle

Muscle structure of a man, rear view: 1 – posterior head of the humerus; 2 – teres minor muscle; 3 – teres major muscle; 4 – infraspinatus muscle; 5 – rhomboid muscle; 6 – extensor muscle of the wrist; 7 – brachioradialis muscle; 8 – flexor carpi ulnaris; 9 – trapezius muscle; 10 – rectus spinalis muscle; 11 – latissimus muscle; 12 – thoracolumbar fascia; 13 – biceps femoris; 14 – adductor magnus muscle of the thigh; 15 – semitendinosus muscle; 16 – thin muscle; 17 – semimembranosus muscle; 18 – calf muscle; 19 – soleus muscle; 20 – long peroneal muscle; 21 – abductor hallucis muscle; 22 – long head of the triceps; 23 – lateral head of the triceps; 24 – medial head of the triceps; 25 – external oblique abdominal muscles; 26 – gluteus medius muscle; 27 – gluteus maximus muscle

The structure of a woman's muscles, front view: 1 – scapular hyoid muscle; 2 – sternohyoid muscle; 3 – sternocleidomastoid muscle; 4 – trapezius muscle; 5 – pectoralis minor muscle (not visible); 6 – pectoralis major muscle; 7 – serratus muscle; 8 – rectus abdominis muscle; 9 – external oblique abdominal muscle; 10 – pectineus muscle; 11 – sartorius muscle; 12 – long adductor muscle of the thigh; 13 – tensor fascia lata; 14 – thin muscle of the thigh; 15 – rectus femoris muscle; 16 – vastus intermedius muscle (not visible); 17 – vastus lateralis muscle; 18 – vastus medialis muscle; 19 – calf muscle; 20 – tibialis anterior muscle; 21 – long extensor of the toes; 22 – long tibialis muscle; 23 – soleus muscle; 24 – anterior bundle of deltas; 25 – middle bundle of deltas; 26 – brachialis muscle; 27 – long biceps bundle; 28 – short biceps bundle; 29 – brachioradialis muscle; 30 – extensor carpi radialis; 31 – pronator teres; 32 – flexor carpi radialis; 33 – palmaris longus muscle; 34 – flexor carpi ulnaris

Muscle structure of a woman, rear view: 1 – posterior bundle of deltas; 2 – long triceps bundle; 3 – lateral triceps bundle; 4 – medial triceps bundle; 5 – extensor carpi ulnaris; 6 – external oblique abdominal muscle; 7 – extensor of the fingers; 8 – fascia lata; 9 – biceps femoris; 10 – semitendinosus muscle; 11 – thin muscle of the thigh; 12 – semimembranosus muscle; 13 – calf muscle; 14 – soleus muscle; 15 – short peroneus muscle; 16 – flexor pollicis longus; 17 – teres minor muscle; 18 – teres major muscle; 19 – infraspinatus muscle; 20 – trapezius muscle; 21 – rhomboid muscle; 22 – latissimus muscle; 23 – spinal extensors; 24 – thoracolumbar fascia; 25 – gluteus minimus; 26 – gluteus maximus muscle

Muscles have quite a variety of shapes. Muscles that share a common tendon but have two or more heads are called biceps (biceps), triceps (triceps), or quadriceps (quadriceps). The functions of the muscles are also quite diverse, these are flexors, extensors, abductors, adductors, rotators (inward and outward), levator, depressor, straightener and others.

Types of muscle tissue

Characteristic structural features allow us to classify human muscles into three types: skeletal, smooth and cardiac.

Types of human muscle tissue: I - skeletal muscles; II - smooth muscles; III - cardiac muscle

• Skeletal muscles. The contraction of this type of muscle is completely controlled by the person. Combined with the human skeleton, they form the musculoskeletal system. This type of muscle is called skeletal precisely because of its attachment to the bones of the skeleton.
• Smooth muscles. This type of tissue is present in the cells of internal organs, skin and blood vessels. The structure of human smooth muscles implies that they are located mostly in the walls of hollow internal organs, such as the esophagus or bladder. They also play an important role in processes that are not controlled by our consciousness, for example in intestinal motility.
• Heart muscle (myocardium). The work of this muscle is controlled by the autonomic nervous system. Its contractions are not controlled by human consciousness.

Since the contraction of smooth and cardiac muscle tissue is not controlled by human consciousness, the emphasis in this article will be focused specifically on skeletal muscles and their detailed description.

Muscle structure

Muscle fiber is a structural element of muscles. Separately, each of them represents not only a cellular, but also a physiological unit that is capable of contracting. The muscle fiber has the appearance of a multinucleated cell; the fiber diameter ranges from 10 to 100 microns. This multinucleated cell is located in a membrane called the sarcolemma, which in turn is filled with sarcoplasm, and within the sarcoplasm there are myofibrils.

Myofibril is a thread-like formation that consists of sarcomeres. The thickness of myofibrils is usually less than 1 micron. Taking into account the number of myofibrils, white (aka fast) and red (aka slow) muscle fibers are usually distinguished. White fibers contain more myofibrils but less sarcoplasm. It is for this reason that they contract faster. Red fibers contain a lot of myoglobin, which is why they got their name.

Internal structure of human muscle: 1 – bone; 2 – tendon; 3 – muscular fascia; 4 – skeletal muscle; 5 – fibrous membrane of skeletal muscle; 6 – connective tissue membrane; 7 – arteries, veins, nerves; 8 – bundle; 9 – connective tissue; 10 – muscle fiber; 11 – myofibril

The work of muscles is characterized by the fact that the ability to contract faster and stronger is characteristic of white fibers. They can develop force and speed of contraction 3-5 times higher than slow fibers. Anaerobic physical activity (working with weights) is performed primarily by fast-twitch muscle fibers. Long-term aerobic physical activity (running, swimming, cycling) is performed primarily by slow-twitch muscle fibers.

Slow fibers are more resistant to fatigue, while fast fibers are not adapted to prolonged physical activity. As for the ratio of fast and slow muscle fibers in human muscles, their number is approximately the same. In most of both sexes, about 45-50% of the muscles of the limbs are slow muscle fibers. There are no significant gender differences in the ratio of different types of muscle fibers in men and women. Their ratio is formed at the beginning of a person’s life cycle, in other words, it is genetically programmed and practically does not change until old age.

Sarcomeres (components of myofibrils) are formed by thick myosin filaments and thin actin filaments. Let's look at them in more detail.

Actin– a protein that is a structural element of the cell cytoskeleton and has the ability to contract. It consists of 375 amino acid residues and makes up about 15% of muscle protein.

Myosin- the main component of myofibrils - contractile muscle fibers, where its content can be about 65%. The molecules are formed by two polypeptide chains, each of which contains about 2000 amino acids. Each of these chains has a so-called head at the end, which includes two small chains consisting of 150-190 amino acids.

Actomyosin– a complex of proteins formed from actin and myosin.

FACT. For the most part, muscles consist of water, proteins and other components: glycogen, lipids, nitrogen-containing substances, salts, etc. Water content ranges from 72-80% of the total muscle mass. Skeletal muscle consists of a large number of fibers, and characteristically, the more fibers there are, the stronger the muscle.

Muscle classification

The human muscular system is characterized by a variety of muscle shapes, which in turn are divided into simple and complex. Simple: spindle-shaped, straight, long, short, wide. Complex muscles include the multicipital muscles. As we have already said, if the muscles have a common tendon, and there are two or more heads, then they are called biceps (biceps), triceps (triceps) or quadriceps (quadriceps), and multitendon and digastric muscles are also multi-headed. The following types of muscles with a certain geometric shape are also complex: quadrate, deltoid, soleus, pyramidal, round, serrated, triangular, rhomboid, soleus.

Main functions muscles are flexion, extension, abduction, adduction, supination, pronation, raising, lowering, straightening and more. The term supination means outward rotation, and the term pronation means inward rotation.

By grain direction muscles are divided into: rectus, transverse, circular, oblique, unipennate, bipennate, multipennate, semitendinosus and semimembranosus.

In relation to the joints, taking into account the number of joints through which they are thrown: single-joint, double-joint and multi-joint.

Muscle work

During contraction, actin filaments penetrate deep into the spaces between myosin filaments, and the length of both structures does not change, but only the total length of the actomyosin complex is reduced - this method of muscle contraction is called sliding. The sliding of actin filaments along myosin filaments requires energy, and the energy required for muscle contraction is released as a result of the interaction of actomyosin with ATP (adenosine triphosphate). In addition to ATP, water plays an important role in muscle contraction, as well as calcium and magnesium ions.

As already mentioned, muscle function is completely controlled by the nervous system. This suggests that their work (contraction and relaxation) can be controlled consciously. For the normal and full functioning of the body and its movement in space, muscles work in groups. Most of the muscle groups in the human body work in pairs and perform opposite functions. It looks like this: when the “agonist” muscle contracts, the “antagonist” muscle stretches. The same is true vice versa.

• Agonist- a muscle that performs a specific movement.
• Antagonist- a muscle that performs the opposite movement.

Muscles have the following properties: elasticity, stretching, contraction. Elasticity and stretching give the muscle the ability to change in size and return to its original state, the third quality makes it possible to create force at its ends and lead to shortening.

Nerve stimulation can cause the following types of muscle contraction: concentric, eccentric and isometric. Concentric contraction occurs in the process of overcoming the load when performing a given movement (lifting up when pulling up on a bar). Eccentric contraction occurs in the process of slowing down movements in the joints (lowering down when pulling up on a bar). Isometric contraction occurs at the moment when the force created by the muscles is equal to the load exerted on them (keeping the body hanging on the bar).

Muscle functions

Knowing the name and location of this or that muscle or group of muscles, we can move on to studying the block - the function of human muscles. Below in the table we will look at the most basic muscles that are trained in the gym. As a rule, six main muscle groups are trained: chest, back, legs, shoulders, arms and abs.

FACT. The largest and strongest muscle group in the human body is the legs. The largest muscle is the gluteus. The strongest is the calf muscle; it can hold weight up to 150 kg.

Conclusion

In this article, we examined such a complex and voluminous topic as the structure and functions of human muscles. When we talk about muscles, we of course also mean muscle fibers, and the involvement of muscle fibers in the work involves the interaction of the nervous system with them, since the execution of muscle activity is preceded by the innervation of motor neurons. It is for this reason that in our next article we will move on to consider the structure and functions of the nervous system.

Muscles provide:

human movement,

The work of individual parts of his body and many internal organs (heart, lungs, stomach, etc.).

Muscles are made up of muscle tissue.

Distinguish between muscles Smooth AndSkeletal :

1.Smooth muscles form the walls of blood vessels, respiratory tract, stomach, and intestines.

Smooth muscles contract slowly and can remain in this state for a long time.

They take part in the work of internal organs and regardless of our will controlled by the autonomic nervous system and humorally.

Smooth muscles provide motility of internal organs.

2.Skeletal muscles- This striated muscles head, torso and limbs.

Skeletal muscles contract quickly.

Their work ensures voluntary movements.

Skeletal muscles provide human movement in space.

Structure of Skeletal Muscle:

Consists of striated muscle fibers collected in bunches;

Outside, each of the muscle bundles and the entire muscle as a whole are covered with connective tissue shells;

Muscles are attached to bones either directly or through tendons. One end of the muscle head, is attached to one bone, the second, tail, through a joint or joints - to another bone so that when it contracts, the bones move;

Each muscle has blood vessels and nerves.

A muscle can only contract when a signal from the central nervous system comes to it. If the nerve is damaged, the muscle will not contract.

For normal muscle function, nutrients and oxygen supplied by the blood are necessary, since the energy of muscle contraction is bound with biological oxidation of organic substances muscle fiber. The breakdown products formed during muscle work are carried away by the blood. This is why deterioration in blood supply disrupts muscle activity and often causes pain.

Feel.

Structure of the Double and TricephalicShoulder Muscles:

1 - heads of the biceps muscle;

2 - belly of the biceps muscle;

3 - tail of the biceps muscle;

4 - tail of the triceps muscle;

5 - belly of the triceps muscle;

6 - heads of the triceps muscle

The main property of muscle tissue is contractility. The work of muscles is based on this property. IN in an excited state, the muscle shortens and thickens-is shrinking, then, at rest, it relaxes and returns to its previous size.

When contracting, muscles perform work to move the body, limbs or hold a load.

Major Skeletal Muscle Groups

I.MusclesHeads - This 1.Chewable and 2. Facial muscles:

1.Masticatory muscles They move the lower jaw, ensure chewing of food and participate in the formation of speech sounds.

Touch your temples and try chewing movements. You will feel how the temporal muscles move under your hand; they belong to the masticatory muscles. Other masticatory muscles can be easily detected if you move your hand a few centimeters forward from the angle of the lower jaw (towards the chin).

2. Facial muscles change facial expression. With the help of these muscles, a person’s face can express feelings of joy and grief, kindness and anger, friendliness and dissatisfaction. The muscles of the mouth are involved in the formation of speech sounds.

The facial muscles are attached to the bones at one end and to the skin at the other.

Of the facial muscles, it is easy to find the orbicularis of the eyes and the orbicularis of the mouth. The latter, together with other muscles, not only changes facial expression, but is also necessary for a person to be able to speak and eat.

Muscles of the Head:

1 - lowering the corner of the mouth;

2 - circular mouth;

3 - circular eyes;

4 - temporal;

5 - sternocleidomastoid;

Musculoskeletal system

Functions:

ü Support

ü Motor

ü Protective

ü Hematopoietic

Bone composition:

Bone is a complex organ of dense, hard connective tissue containing calcified elements.

Organic substances – 30% (ostein, collagen) – give elasticity to bones

Inorganic substances:

Water – 10-20%; Mineral salts (calcium, phosphorus, magnesium) – 60% – give bones hardness

With age, the amount of organic substances decreases and inorganic substances increase, which contributes to increased bone fragility and more frequent fractures.

Types of bones:

ü Tubular: long (humeral, radial, femoral, tibia and tibia); short (metacarpus and metatarsals, phalanges of the fingers)

ü Spongy (ribs, sternum, vertebrae) - consist of a spongy substance covered with a thin layer of compact substance

ü Flat (pelvic bones, skull roof bones, shoulder blades)

ü Mixed (bones of the base of the skull) – formed as a result of the fusion of several parts and have a complex shape

ü Pneumatic (upper jaw, frontal, sphenoid, ethmoid) – have cavities inside

Structure of the tubular bone:

Bone growth:

Bones grow in length due to the division of cartilage cells; in thickness - due to cell division of the inner layer of the periosteum

Bone growth is regulated by growth hormones produced by the pituitary gland; in case of excess growth hormones from an early age – gigantism; in adulthood, excess growth hormones leads to disproportionate bone growth - acromegaly; in case of shortage growth hormones - dwarfism

Bone connections:

Fixed joint - pelvic bones, skull bones Semi-movable - vertebrae, ribs with sternum Movable (joint): consists of an articular capsule, intracapsular ligament, cartilaginous meniscus, joint fluid and articular cartilage. The joint capsule (capsule) consists of connective tissue with many collagen fibers. The capsule is attached to the periosteum at the ends of the bones of the joint. Its elasticity allows the bones to move in the joint. The cartilaginous meniscus is a lining of fibrous cartilage tissue that lies between the articular surfaces of bones. It allows bones with different articular surface shapes to fit tightly together. The meniscus also maintains joint strength and directs synovial fluid to the area of ​​greatest friction. The joint fluid is formed by tissue fluid; its appearance and consistency resembles egg white; its viscosity may vary. Articular cartilage helps reduce friction in the joint and also serves as good shock absorbers during impact.

Human skeleton:

Scull

Brain department: paired temporal, paired parietal, unpaired frontal, unpaired occipital, unpaired ethmoid, unpaired sphenoid

Facial section: paired upper jaw, unpaired lower jaw (the only movable bone of the skull), about 20 bones in total

Features:

motor(movement of the body and its parts in space),

protective(the abdominal organs are protected by the abdominal press), formative(to some extent determine the shape of the body and its size),

energy(conversion of chemical energy into mechanical and thermal energy).

Skeletal muscle formed by bundles of muscle fibers, which consist of a muscle fiber core, contractile filaments, a covering membrane and blood vessels. On the outside, the muscle is covered with a connective tissue membrane - fascia. There are superficial and deep fascia. Muscles are attached to bones by tendons. Tendons They consist of dense fibrous connective tissue and have high strength.

Characteristics of the main groups of skeletal muscles

In physiology, muscles are classified by function and the following groups are distinguished: flexor and extensor muscles; synergistic muscles(different muscles involved in the same movement) and antagonist muscles(participating in opposite movements); adductors and abductors