Our body, as well as its individual systems and organs, perform dozens of different functions. It’s difficult to briefly talk about all of them, so now we’ll focus only on one thing - locomotor. It refers to the musculoskeletal system. The bones, being a kind of "leverage", are set in motion by the muscles through the central nervous system, thereby causing a variety of movements. This is the locomotor function. And now about everything that concerns her, it is worth telling in a little more detail.
The concept of locomotion
It should be considered first. Locomotion is the movement of a person in space, due to his active actions. Animals, by the way, this term also applies.
In medicine, under this concept, a type of motor activity is perceived , which is associated with the movement of a person in space. Its result, respectively, are motor acts.
It should also be noted that locomotion is one of two categories of behavior. The second is manipulation. Locomotion is attributed to instinctive movements. What does this fact mean? The fact that the locomotor function is a feature related to the rigid musculoskeletal system, allowing only minimal variability of movements.
But that is not all. It is also worth knowing that the locomotor problem solving, manifested, for example, in choosing the right path in the maze, often leads to the formation of complex skills. In other words, it becomes an element of intellectual action.
Movement as a phenomenon
It was briefly described above that this is a locomotor function. The concept of motion should also be studied separately.
This is, firstly, one of the key manifestations of life, which ensures the active interaction of a person with the environment. And the movement is presented in many different forms. It appears as a result of many processes occurring at the tissue, cellular, systemic and organ levels.
The movements that a person’s locomotor function performs are the result of skeletal muscle contraction. After all, it is precisely due to them that one or another pose is supported, individual links or the whole body are moved.
It is worth mentioning more about the protective and support functions. In the body, absolutely everything is interconnected, so these concepts are directly related to locomotion.
So, for example, the protective function of the skeleton is manifested in the presence of various cavities (chest, pelvic, cranial, vertebral). All this is a reliable protection for the vital organs located in them.
The description of the support function is elementary. The skeleton is a real support for the internal organs and muscles. They are fixed to the bones, thereby being held in position.
Movement Classification
Talking about locomotor function, this topic also needs to be addressed. When classifying movements, the following nuances are taken into account:
- The nature of the position of the parts of the body. For example, extension and bending.
- Mechanical properties. In particular, ballistic and rotational.
- Functional Values. This refers to the protective and indicative.
All movements in humans are controlled by brain activity. It is always aimed at the implementation of a specific task, which, in turn, is modeled in a sequence of muscle contractions. This form of activity is called arbitrary or conscious.
There is also the concept of the coordinated activity of several muscle groups. This is already called coordination. It is very important in the manifestation of endurance, speed, strength and agility.
Reflexes
They are directly related to locomotor function. Reflexes are the same motor reactions. They cause irritation of the sensitive nerve endings and directly excite the central nervous system, which spreads to the muscles (effectors) through centrifugal fibers.
As you know, distinguish between conditioned and unconditioned reflexes. Otherwise, they are called acquired and congenital motor reactions. What is the difference? Congenital reactions are realized through reflex arcs. And acquired ones appear on the basis of unconditioned reflexes during individual learning. It is for this reason that they are considered more ductile.
In both cases, there is a universal classification, which includes:
- The modality (sensory nature) of the stimulus, which acts on the afferent nerve ending. It is tactile, sound and light.
- The level of nerve structures involved in the organization of the notorious motor reflex. They are cortical, stem and segmental.
- A characteristic of the environment that stimulates receptors. By the way, they are extero-, inter- and proprioceptive.
- The amount of motor activity. There are both simple reflexes (say, knee-jerk reflexes) and complex ones (the same providing movement in space).
- Biological significance. This refers to sexual, indicative, research, defensive and nutritional reflexes.
Physiological features
It should return directly to the locomotor function. It provides the interaction of two systems:
- Central. Involves the cerebral cortex, subcortical formations, motor zones, the pyramidal bundle, as well as the brain stem, cerebellum and columns of the spinal cord.
- Peripheral. Only afferent nerve fibers and proprioreceptors are involved. However, they are concentrated everywhere - in the articular surfaces, muscles, tendons and ligaments.
When receptors are irritated, impulse occurs. It is transmitted through the nerve guides to the spinal cord, and then to the central nervous system. Locomotor function is controlled by a motor analyzer, and those impulses that come from neurons are then transmitted to the muscles. This is how this process is carried out, in simple terms.
Disorders
It is impossible not to mention the violation of static-locomotor functions. Disorders occur if one of the following occurs:
- Damage to the central nerve formations.
- Transmission from a nerve to a muscle of an impulse through an end plate.
- Violation of the excitation along the nerve paths.
Disorders of locomotor muscle function are divided into ataxia, hypokinesia, astasia, asthenia and hyperkinesia. Each phenomenon should be discussed separately.
Hypokinesia
It is characterized by either a weakening of the ability to voluntary movements, or its complete loss. In other words, hypokinesia is a state of insufficient motor activity.
As a rule, it occurs against the background of mental or neurological disorders. A stupor (apathic, depressive or catatonic), depressive syndrome, parkinsonism can become a provoking factor. A simpler reason is a sedentary lifestyle and sedentary work.
With hypokinesia, the innervation of the muscles is disturbed. If the function does not fall out completely, the person is overcome by paresis. This is the best deal. Because complete loss is fraught with paralysis. But be that as it may, in both cases, motor neurons are affected.
In fact, anything can provoke hypokinesia. Risk factors include mechanical damage, intoxication, inflammation, tumor growth, invasive and infectious irritants, internal hemorrhage, etc.
Hyperkinesia
In continuation of the topic regarding locomotor and static functions, this phenomenon should also be addressed. Hyperkinesia is a disorder that is accompanied by convulsive, uncontrolled muscle contractions. The reason also lies in the defeat of the central nervous system.
The reasons are divided into two categories:
- Exogenous. These are burns, anaphylaxis, inflammation and infectious diseases (in particular tetanus and rabies).
- Endogenous. Pathologies of hereditary origin, tumors, diabetes, uremia and atherosclerosis are included in this category.
Often, hyperkinesia becomes an “escort” of alkalosis, hypocalcemia, hypoglycemia and hypomagnesemia. Manifested by convulsions, tremors, chorea, teak.
Ataxia
This disorder of static-locomotor function is quite common. It manifests itself in slightly reduced strength indicators of one or another limb. Due to ataxia, movements become awkward and inaccurate, their sequence and continuity are disrupted. Often out of balance.
There is a static ataxia and dynamic. In the first case, the balance is disturbed in a standing position. In the second, there is a violation of coordination directly during movement.
If a person does not have a single type of ataxia, this means that all departments of his central nervous system carry out friendly, highly automated activities.
Asthenia
This violation does not apply to any specific locomotor function (foot, for example, or arm). Asthenia is the general weakness of the body, manifested in a weakening of muscle tone and rapid fatigue.
The reason is cerebellar damage. It is his dysfunction that leads to the fact that the inhibitory effect on a variety of arbitrary acts is weakened. Movements become angular, sharp, falls can occur. Almost any physical stress causes instant fatigue and a state of oppression that replaces it.
Provoking factors can be very different. The list includes:
- Diseases of the cardiovascular system.
- Gastrointestinal problems.
- Pathology of the genitourinary system.
- Hematologic ailments.
- Endocrine diseases.
- Systemic pathologies (starting with allergies, ending with oncological neoplasms).
- Congenital malformations.
- Infectious diseases.
- Different types of dementia.
But more often the causes of asthenia are metabolic problems, lack of trace elements, poor nutrition and nervous tension.
Astasia
The topic of supporting protective and locomotor function of the skeleton should be completed by a discussion of this disorder. Astasia is a rather atypical pathology. This is called a violation of the ability to stand. The reason is a violation of the coordination of the muscles of the body with rather impressive lesions of the corpus callosum and frontal lobes.
Very often, astasias affect people suffering from conversion (dissociative) disorders. They used to be called hysteria. Also, astasia is often combined with abasia (this is a loss of walking ability).
Symptoms are specific. In the most severe cases, people cannot even stand on their own. The best deal is simply gait disturbance, loss of balance and tremor of limbs.