Contents
The nervous system consists of approximately 150 billion of these cells and is responsible for all processes in the human body. It consists of the spinal cord and brain (CNS) and the peripheral nervous system. Its basic unit is the neuron. The neuron is capable of receiving, processing and sending electrical impulses. Neurons are classified as ascending (transmitting data from the receptors to the UON) and descending (conducting data in the opposite direction).
Construction of a single neuron
Neuron it is a cell consisting of a perikaryon (or cell body) and appendages. The projections are referred to as dendrites and axons. Axons can reach a size of up to 1 meter. The size of the neuron is closely related to the size of the cell body. Neurons arise as a result of the process of neurogenesis. Neuron is a nerve cell, the outer part of which is surrounded by a cell membrane. It is supposed to act as a barrier to harmful substances. This membrane enables the transport of substances such as oxygen, carbon dioxide and water. Inside the neuron are the cytoplasm, nucleus with chromosomes, Golgi apparatus and mitochondria. Golgi apparatus in neuronie serves the function of redirecting substances that are produced in the body to the right places. The mitochondrion is responsible for cellular metabolism. Another ingredient nerve cell (neuron) there is a Nissl body, or a tigroid. This is where the synthesis of cellular proteins takes place. This substance may be present in neuronie in the form of lumps or dust.
Types of neurons according to their functions
There are several types of neurons in the nervous system. These are associative, motor, and sensory neurons. Each of these groups has different functions in the body. Neurons mating cells are located in the central part of the nervous system, and their task is to transmit nerve impulses between neurons motor and sensory. Second group neurons (i.e., motor neurons) receive the nerve impulses sent by the neurons associative by passing them to muscles or glands. The third group of neurons are sensory neurons (also known as sensory neurons), which receive nerve impulses (heat, pain, etc.) from the skin and transmit them to the central nervous system.
What is a motor neuron, and what is one of its most serious diseases?
Term «Motor neuron» refers to a type of nerve cell that transmits impulses to muscles or glands after being excited by other neurons. It happens that motor-type neurons are part of the reflex arc – provided that it is connected to the muscle fiber. Motor neuron it is also the building block of the ventral and anterior roots in the spinal cord. One of the most serious diseases motor neuron includes amyotrophic lateral sclerosis. It is an incurable and progressive disease. Amyotrophic lateral sclerosis disease is characterized, inter alia, by damage to the peripheral and central motor neurons, destruction of the medulla and spinal cord cells.
It occurs much more often in men than in women. The first symptom of the disease motor neuron they concern muscle atrophy and paresis of upper and lower limbs. The mobility of a person then decreases, which in turn leads to paralysis and death due to the stoppage of the respiratory muscles. The disease causes the death of a person within three to five years. There is no effective treatment for this disease motor neuron.