Neuron Structure and Function The neuron cell has all components of normal eukaryotic cells.
Neurons Meaning: Neurons, which are also called the nerve cell, are the structural and the functional units of the nerve cell in vertebrates and most invertebrates. They are independent, morphological, functional and trophic entities and develop from the neural plate of the ectoderm. They are different from glial cells in their ability to generate action potentials in the release of neurotransmitters which are neuroactive substances. Neurons are also polarised cells which receive information at certain locations on their plasma membrane and release neurotransmitters to other cells. Neuron Definition A neuron could be defined as a greyish granular cell that is the fundamental unit of the nervous system and functions to transmit information to different parts of the body. Neuron Structure and Function The neuron cell has all components of normal eukaryotic cells. However, in addition to these components, there are five parts of a neuron which give it its form. A detailed discussion of the entire neuron structure is given below. Neuron Parts and their Functions:
The axon hillock regulates and keeps an account of the total excitatory and inhibitory signals. If the total number of these signals exceeds a certain threshold, an action potential is triggered and an electrical signal will be transmitted down the axon away from the soma. In a normal resting state, a neuron possesses an internal polarisation of approximately -70mV. When a signal is received by a cell, it causes sodium ions to enter the cell and reduce the polarisation. When the axon hillock is depolarised to a certain threshold, an action potential will transmit the electrical signal down the axon to the synapses. It should be noted that the action potential is an all-or-nothing process i.e. the signals are not partially transmitted.
The gap at the end of the terminal button is called a synapse. Neurotransmitters carry the neural or electrical signal across the synapse to other neurons. When an electrical signal reaches the terminal buttons, neurotransmitters are released into the synaptic gap. The terminal buttons convert those electrical impulses into chemical signals. The neurotransmitters then cross the synapse where they are then received by other neurones. [Image will be Uploaded Soon] Neuron Diagram and Functions Neuron Function Neurons send electrical signals through action potentials which is a shift in neurons electrical potential caused by a flow of ions in and out of the neural membrane. Action potentials have the ability to trigger both chemical and electrical synapses: Chemical Synapses: In this type of synapses, the action potential affects other neurons through a gap present neurons known as the synapse. After the action potential is generated it is carried along the axon to a presynaptic ending which triggers neurotransmitters. These chemical messengers then cross the synaptic cleft and bind to receptors in the post-synaptic ending of a dendrite. Electrical Synapses: Electrical synapses are observed when two neurones are connected via a gap junction which is much smaller than a synapse and includes ion channels which facilitate the direct transmission of a positive electrical signal. Due to this, electrical synapses are much faster than chemical synapses. Classification of Neurons There are three different types of neurons and they are discussed below: 3 Types of Neurons and Functions
Q1: Give the Classification of Neurons Based on Polarity. Ans: Based on polarity and the number of axons and dendrites, neurons can be:
[Image will be Uploaded Soon] Q2: What are Interneurons and What is their Function? Ans: Interneurons can be referred to as neural intermediaries which are found in the brain and the spinal cord. They pass sensory signals from sensory neurons and other interneurons to motor neurons and other interneurons. Also, they often form complex circuits that help you to react to external stimuli. For example, when you touch something very cold, sensory neurons in your fingertips send a neural signal to interneurons in your spinal cord. Some interneurons transmit this signal to the motor neurons in the hand, which makes humans move their hand away. Q3: Where is Neuron Present in the Body? Ans: In vertebrates, the majority of neurons are located in the central nervous system. However some of them reside in peripheral ganglia, and many sensory neurons are located in sensory organs such as the retina and cochlea. Q4: Describe the Structure and Function of a Neuron? Ans: Please have a look at the neuron structure and function section.
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