Functions of the spinal cord of man: reflex and conductive
The spinal cord is located in spinal canal. He is part of the Central nervous system (CNS). The main functions of the spinal cord — segmental reflex and conductive. To understand how they are implemented, consider the organization of the spinal cord and function of the spine as the protector of the spinal cord from damage.
Spinal cord: structure
Externally, the spinal cord is a bundle of brain tissue, round in all departments except the area of the bulges, where it is of tapered form from front to back. At the level of the 3rd cervical vertebra and the 1st thoracic is cervical thickening. At the level of 10-12 thoracic vertebrae is the lumbar-sacral.
At the top of the spinal cord of the person goes in oblong, at the bottom, gradually estancias forms in the first lumbar vertebra the brain cone. The length of the spinal cord in the adult is 41-45 cm, diameter 1-1. 5 cm Front and back it is divided by two longitudinal furrows on the left and right halves. Has 3 shell mezenhimnogo of origin: the solid (outer), the arachnoid and soft (vascular).
The spinal cord plays an important function to supply the internal organs and skeletal muscles (except head muscles) of a human nerve fibers, which ensures their communication with the CNS. Organization of the spinal cord consists of 31 segments (Narmer) associated directly with the working bodies and receptors. This:
- 8 cervical segments that control the muscles of the head, neck, chest cavity, heart, lungs, upper extremities;
- 12 thoracic and 5 lumbar that control the abdominal organs and muscles of the trunk;
- 5 sacral and 1 coccygeal controlling the muscles of the lower extremities and lower abdomen.
Around the canal with the spinal fluid is gray matter, resembling in cross section a butterfly and consists of the bodies of nerve cells. There are front, side and rear horns. Gray matter contains intercalated and motor neurons. Around the gray matter is white matter containing the axons of neurons that form the ascending and descending path.
In the center of the spinal cord is the channel where is cerebrospinal fluid.
Reflexes and motor function
As a reflex center spinal cord is able to control simple and complex motor and autonomic reflexes. There are:
Conduction function of the spinal cord is to conduct nerve impulses.
There are two ways in which carry out bidirectional communication of the spinal cord with the periphery: sensitive (afferent) and motor (efferent). The afferent pathways are used for communication with the receptor, efferent to internal organs and skeletal muscles. The chain looks like. For example, there have been some events in the external (internal) environment of the person.
Functional organization of the brain provides receiving and processing of information, creation of own programmes of action and monitoring their implementation and functional organization of the spinal cord — coordination reflex activity of the CNS.
The brain performs the function of control over the work of the spinal cord. For example, when a person gives blood, he doesn’t pulls his hand, although the pain is present, because the brain inhibits the spinal reflex action.
Causes and risk of damage to the spinal cord
Causes of damage can be injury in road traffic accidents, falling from heights, diving, sports. Problems can also occur as a result of various bumps and injuries, aneurysm, infectious diseases and other reasons. According to statistics, 80% of injuries in which the damaged spinal cord, are men 16-30 years. The most common cause of traumatic cases is alcohol use. Damage can lead to irreversible processes, so as to recover the body can not.
Organization of the spinal cord provides for its protection of the spinal column (vertebrae). Function of the spine, in addition to the functions of movement and balance, include reflex, cushioning and protective processes. In the normal state the spinal cord is protected by bones of the human spine. In case of violation of the protective functions of the spine, for example, in case of injury, the spinal cord may be subjected to compression (compression) or damage.
The spinal cord can be damaged in the upper part, which leads to paralysis. For example, fractures of the first and second cervical vertebrae of the human spine led to paralysis of all limbs. If damage is located in the lower parts of the spine you can be paralyzed legs and lower torso. In case of partial damage, its functions are incomplete: we still have some degree of sensitivity and motor functions. Its full damage leads to a complete (or almost complete) loss of motor function and sensitivity below the lesion.
Modern science can’t completely cure the spinal cord injury person. But progress does not stand still, it develops new methods of treatment, such as stem cell therapy, bionic exoskeletons, innovative electrical stimulation. Are new drugs that are intended to stimulate, regenerate nerve cells, improve nerve function.