Motor reaction (related to muscle contraction) are one of the most common types of reflex reactions (see Reflexes), which provide orientation and movement of the body in space.
The nature of muscle contractions all motor responses can be divided into two categories: reactions, providing the tone of the muscle fibers,- long tonic contractions; reaction, providing local motion - physical.
Themselves physical motor responses may vary in the direction of the movement. In this regard, there are movements, providing flexion, extension, coercion, abduction, rotation limbs in the joint. Muscles that provide these types of motor reactions, were given appropriate names: flexors, extensor, etc.,
Very often these muscles act as antagonists. So, bend the legs at the knee, provide reduction of flexors, accompanied by a relaxation of the extensor. But often these muscles act as synergistic, i.e. simultaneously. So, when you commit legs at the knee requires the simultaneous reduction of various muscle groups.
Tonic and physical muscle reactions simultaneously, providing a holistic motor act.
No local muscle movement (for example, the show of hands) can not be effected without prior move the center of gravity of the body and fixing poses. Otherwise, the people who raised their hand, immediately fell into the breach equilibrium of the body.
Any single motor act (walking, running, jumping and so on) can be studied from the point of view of participation of various muscle groups in the implementation of this act, amplitude of movements, degree of flexion or extension of a limb in a particular joint, etc. Section physiology involved in the study of the mechanics of motion of animals and humans, called biomechanics.
Any, even the simplest motor act is the result of a very complex and finely coordinated work of many muscle groups, which in turn reflects a very complex processes in the Central nervous system. An important role is played by the motor, or kinesthetic, the analyzer. The latter, like any other, consists of three main parts: peripheral submitted by proprioceptors (muscle spindles, receptors Golgi bullock, Pacini), located in the heart of locomotor system (in muscles, tendons, joint capsule and so on); provodnikova division, which consists of nerve fibers that conduct proprioceptive excitation to the bark of the big hemispheres; the cortical level, presents the cortical area that receives stimulation of muscular-articular receptors.
Using motion analyzer can be estimated force of muscle contraction, the amplitude and direction of movement, position of a body in space, etc.
The development of traffic in children - see the baby.
Pathology movements. Disorders of the motor reactions occur in defeat pyramid path (Central motor neuron), the basal ganglia of the brain stem and cerebellum, spinal cord and peripheral neuron coming from the cells of the anterior horn of the spinal cord (in the front of the roots). Complete loss of movement is called paralysis, partial paralysis.
At the Central paralysis there is a lack of active movements, reduced muscle strength, increased muscle tone, increase tendon reflexes, the emergence of pathological reflexes and abnormal friendly movements. With the peripheral paralysis marked drop arbitrary, friendly and reflex movements, atony, areflexia, muscle atrophy, in some cases, twitching.
With the defeat ekstrapiramidna system appears Oligocene or bradykinesia (see) and hyperkinesia (see). When damage to the cerebellum (see) there is an excessive amount of involuntary movements and violation of their coordination. With the defeat of the parietal lobe, and rear pillars of the spinal cord marked disorders of sensitivity.