Examples of Neurons in the following topics:
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- Afferent neurons convey information from tissues and organs into the central nervous system (e.g. sensory neurons).
- Efferent neurons transmit signals from the central nervous system to the effector cells (e.g. motor neurons).
- Another way in which neurons are classified is by their effect on target neurons.
- A neuron releases a neurotransmitter that binds to chemical receptors on the target neuron .
- Other types of neurons include excitatory motor neurons in the spinal cord that release acetylcholine, and inhibitory spinal neurons that release glycine.
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- A typical neuron consists of a cell body and neuronal processes such as dendrites and axon.
- These extensions are the conducting region of the neuron.
- The cell body is the major biosynthetic center of the neuron.
- Interneurons act as relays between neurons in close proximity to one another.
- 1: Unipolar neuron, 2: Bipolar neuron, 3: Multipolar neuron, 4: Pseudounipolar neuron
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- The nervous system is a network of cells called neurons that coordinate actions and transmit signals between different parts of the body.
- Central to the functioning of the nervous system is an extensive network of specialized cells called neurons.
- The peripheral nervous system (PNS) consists of sensory neurons, motor neurons, and neurons that communicate either between subdivisions of the PNS or connect the PNS to the CNS .
- Central neurons, which in humans greatly outnumber the sensory and motor neurons, make all of their input and output connections with other neurons.
- Electrical impulses travel along the axon of a neuron.
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- A nucleus can either by a relatively compact collection of neurons or a distinctly identifiable group of neurons spread over a large area.
- In the peripheral nervous system, a cluster of neurons is called a ganglion.
- Ganglia are composed mainly of neuron cell bodies (somata) and dendritic structures.
- Satellite glial cells (SGCs) also surround neuron cell bodies within ganglia.
- They supply nutrients to the surrounding neurons and also have some structural function.
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- The ANS is unique in that it requires a sequential two-neuron efferent pathway; the preganglionic neuron must first synapse onto a postganglionic neuron before innervating the target organ.
- The preganglionic, or first neuron will begin at the "outflow" and will synapse at the postganglionic, or second neuron's cell body.
- These cell bodies are GVE (general visceral efferent) neurons and are the preganglionic neurons.
- There are several locations upon which preganglionic neurons can synapse with their postganglionic neurons:
- These are the preganglionic neurons, which synapse with postganglionic neurons in these locations :
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- A synapse is a structural junction that mediates information transfer from one neuron to the next or from one neuron to an effector cell as in muscle or gland.
- The neuron conducting impulses towards the synapse is called presynaptic neuron.
- The neuron transmitting the electrical impulse away from the synapse is called postsynaptic neuron.
- At a synapse , the presynaptic neuron sends information and postsynaptic neuron receives the information.
- Most neurons, function as both as presynaptic and postsynaptic neurons.
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- They also help in the guiding the migration of young neurons.
- Astrocytes control the chemical environment around the neurons.
- Neurons consist of cell body and one or more slender processes.
- Arm like processes extend from the cell body to all neurons.
- Dendrites are motor neurons that are short and have a large surface area for receiving signals from other neurons.
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- There are upper and lower motor neurons in the corticospinal tract.
- These are the upper motor neurons of the corticospinal tract.
- These axons also synapse with lower motor neurons in the ventral horns.
- The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons.
- The lateral tract contains upper motor neuronal axons that synapse on dorsal lateral lower motor neurons, which are involved in distal limb control.
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- A reflex arc defines the pathway by which a reflex travels, from the stimulus to sensory neuron to motor neuron to reflex muscle movement.
- Most reflex arcs involve only three neurons.
- This travels to the spinal cord where it passes, by means of a synapse, to a connecting neuron called the relay neuron situated in the spinal cord.
- When a reflex arc consists of only two neurons, one sensory neuron, and one motor neuron, it is defined as monosynaptic.
- It causes stimulation of sensory, association, and motor neurons.
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- Their numerous radiating processes cling to neurons and their synaptic endings.
- They support and brace the neurons and anchor them to their nutrient supply lines.
- They also play an important role in making exchanges between capillaries and neurons.
- Microglial cells are small and have thorny processes that can touch the neighboring neurons.
- They are also able to monitor the health of neurons by detecting injuries to the neuron.