11/25/2023 0 Comments Unipolar neuron dendriteThere are many neurons in the nervous system-a number in the trillions. These bulbs are what make the connection with the target cell at the synapse. At the end of the axon is the axon terminal, where there are usually several branches extending toward the target cell, each of which ends in an enlargement called a synaptic end bulb. The length of the axon between each gap, which is wrapped in myelin, is referred to as an axon segment. Each gap is called a node of Ranvier and is important to the way that electrical signals travel down the axon. A key difference between myelin and the insulation on a wire is that there are gaps in the myelin covering of an axon. Myelin acts as insulation much like the plastic or rubber that is used to insulate electrical wires. Many axons are wrapped by an insulating substance called myelin, which is actually made from glial cells. Because the axon hillock represents the beginning of the axon, it is also referred to as the initial segment. Within the axon hillock, the cytoplasm changes to a solution of limited components called axoplasm. This is a tapering of the cell body toward the axon fiber. Where the axon emerges from the cell body, there is a special region referred to as the axon hillock. The major parts of the neuron are labeled on a multipolar neuron from the CNS. Figure 1 shows the relationship of these parts to one another. This gives the neuron a polarity-meaning that information flows in this one direction. Information flows through a neuron from the dendrites, across the cell body, and down the axon. The dendrites are usually highly branched processes, providing locations for other neurons to communicate with the cell body. The other processes of the neuron are dendrites, which receive information from other neurons at specialized areas of contact called synapses. It is the axon that propagates the nerve impulse, which is communicated to one or more cells. That single axon can branch repeatedly to communicate with many target cells. Neurons are usually described as having one, and only one, axon-a fiber that emerges from the cell body and projects to target cells. But what makes neurons special is that they have many extensions of their cell membranes, which are generally referred to as processes. The cell body contains the nucleus and most of the major organelles. Parts of a NeuronĪs you learned in the first section, the main part of a neuron is the cell body, which is also known as the soma (soma = “body”). The three-dimensional shape of these cells makes the immense numbers of connections within the nervous system possible. An important part of the function of neurons is in their structure, or shape. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. Neurons are the cells considered to be the basis of nervous tissue. Neurons are important, but without glial support they would not be able to perform their function. Ongoing research pursues an expanded role that glial cells might play in signaling, but neurons are still considered the basis of this function. Glial cells, or glia, are known to play a supporting role for nervous tissue. They are electrically active and release chemical signals to target cells. They are responsible for the computation and communication that the nervous system provides. Neurons are the primary type of cell that most anyone associates with the nervous system. Nervous tissue is composed of two types of cells, neurons and glial cells. Describe the structure of each of the following:.These neurohormones, produced by neurosecretory cells, are normally secreted from nerve cells in the brain that then circulate into the blood.By the end of this section, you will be able to: Neurosecretion is the storage, synthesis and release of hormones from neurons.This neuron contains an axon that has split into two branches one branch runs to the periphery and the other to the spinal cord. A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system.A multipolar neuron is a type of neuron that possesses a single axon and many dendrites (and dendritic branches), allowing for the integration of a great deal of information from other neurons.Bipolar cells are specialized sensory neurons for the transmission of special senses.bipolar neuron or bipolar cell is a type of neuron which has two extensions (one axon and one dendrite). Unipolar neurons have only one structure that extends away from the soma.The neurons are broadly divided into four basic types: unipolar, bipolar, multipolar, and pseudounipolar.
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