On the other hand, data published in November show that in one area of the brain the hippocampus , new neurons CAN grow in adult humans. Neurons can be quite large - in some neurons, such as corticospinal neurons from motor cortex to spinal cord or primary afferent neurons neurons that extend from the skin into the spinal cord and up to the brain stem , can be several feet long!
Types of Neurons Nerve Cells The human body is made up of trillions of cells. Neurons are similar to other cells in the body because: Neurons are surrounded by a cell membrane. Neurons have a nucleus that contains genes. Neurons contain cytoplasm, mitochondria and other organelles. Neurons carry out basic cellular processes such as protein synthesis and energy production.
However, neurons differ from other cells in the body because: Neurons have specialize cell parts called dendrites and axons. Dendrites bring electrical signals to the cell body and axons take information away from the cell body. Neurons communicate with each other through an electrochemical process. Neurons contain some specialized structures for example, synapses and chemicals for example, neurotransmitters.
The Neuron One way to classify neurons is by the number of extensions that extend from the neuron's cell body soma. Neurons can also be classified by the direction that they send information. Sensory or afferent neurons: send information from sensory receptors e. Motor or efferent neurons: send information AWAY from the central nervous system to muscles or glands. Interneurons: send information between sensory neurons and motor neurons.
Most interneurons are located in the central nervous system. Hear It "Neuron" "Axon" "Dendrite" "Nissl" "Mitochondria" "Endoplasmic reticulum" There are several differences between axons and dendrites: Axons Dendrites Take information away from the cell body Smooth Surface Generally only 1 axon per cell No ribosomes Can have myelin Branch further from the cell body Bring information to the cell body Rough Surface dendritic spines Usually many dendrites per cell Have ribosomes No myelin insulation Branch near the cell body What is inside of a neuron?
Nucleus - contains genetic material chromosomes including information for cell development and synthesis of proteins necessary for cell maintenance and survival. Covered by a membrane. They control how the body functions; they stimulate body movement, help people perceive their environment and provide consciousness.
Most cells of the body can replicate and must do so in response to injury or to replace older cells. Mitosis is the process of a cell splitting into two identical cells, or replicating. Unlike most cells of the body, neurons cannot replicate. For that reason, brain and spinal cord injuries are severe, according to the University of Arizona Biology Department.
Related Articles Components of Homeostasis. Definition of Cell Surface Proteins. Cell Characteristics. Explanation of Cell Specialization. A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body. These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.
There are also several different types of neurons responsible for different tasks in the human body. Sensory neurons carry information from the sensory receptor cells throughout the body to the brain. Motor neurons transmit information from the brain to the muscles of the body. Interneurons are responsible for communicating information between different neurons in the body.
The cell bodies of both cell types contain organelles that support the life of the cell, including mitochondria, Golgi bodies, and cytoplasm. Neurons stop reproducing shortly after birth. Generally, when neurons die they are not replaced, although neurogenesis , or the formation of new nerve cells, does occur in some parts of the brain. Neurons have a membrane featuring an axon and dendrites, specialized structures designed to transmit and receive information.
Neurons release chemicals known as neurotransmitters into synapses, or the connections between cells, to communicate with other neurons. There are three basic parts of a neuron : the dendrites, the cell body, and the axon. However, all neurons vary somewhat in size, shape, and characteristics depending on the function and role of the neuron. Some neurons have few dendritic branches, while others are highly branched in order to receive a great deal of information.
Some neurons have short axons, while others can be quite long. The longest axon in the human body extends from the bottom of the spine to the big toe and averages a length of approximately three feet! How do neurons transmit and receive information? In order for neurons to communicate, they need to transmit information both within the neuron and from one neuron to the next. This process utilizes both electrical signals as well as chemical messengers. The dendrites of neurons receive information from sensory receptors or other neurons.
This information is then passed down to the cell body and on to the axon. Once the information has arrived at the axon, it travels down the length of the axon in the form of an electrical signal known as an action potential. Once an electrical impulse has reached the end of an axon, the information must be transmitted across the synaptic gap to the dendrites of the adjoining neuron.
In some cases, the electrical signal can almost instantaneously bridge the gap between the neurons and continue along its path. In other cases, neurotransmitters are needed to send the information from one neuron to the next. Neurotransmitters are chemical messengers that are released from the axon terminals to cross the synaptic gap and reach the receptor sites of other neurons.
In a process known as reuptake, these neurotransmitters attach to the receptor site and are reabsorbed by the neuron to be reused. Neurotransmitters are an essential part of our everyday functioning.
While it is not known exactly how many neurotransmitters exist, scientists have identified more than of these chemical messengers.
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