Spindled – two branches of dendrites are formed from two opposite ends of the neuronal cell body, e.g., bipolar neurons.Adendritic – no branches of dendrites, thus the structure of the dendrite is not like a tree.Dendritic malformation can lead to neurological disorders.ĭepending upon the dendrite morphology and dendrite branch, dendrites can be: This branching morphology and density of the dendrites is dependent upon the type of the dendrite and its function. Dendrite branching acquires different shapes, densities, and morphology. The process of dendritic branching involves multiple steps, wherein the dendrites branch to form synapses with the axons. According to this hypothesis, sensory signals/stimulus from presynaptic neurons to a postsynaptic cell affects the course of synapse formation at the axon and dendrite junction.ĭendrites emanating multiple branching is also referred to as Dendritic arborization or dendritic branching. Image Credit: A Level Biology Dendrite Developmentĭendritic morphogenesis i.e., the dendrite growth and differentiation is affected by several factors that include:Īlthough not much is known about dendrite development and differentiation, a Synaptotropic Hypothesis has been proposed that postulates the dendritic arbor development mechanism. According to the compartmental modeling of dendrites, dendritic spines are the subcellular dendritic compartments.įigure 1: Structure of a neuron and its dendrites. Dendritic spines help to increase the surface area of the neuron and thus increase the susceptibility and detectability of the dendrites. Spines are the dendritic protrusions (not more than 2 µm) and usually have a bulbous end attached through a narrow neck. All the dendrites possess dendritic spines at the synapses.Ribosomes present in the dendrites are involved in the protein synthesis. Additionally, dendrites may carry out protein synthesis and can have independent signaling in association with other neurons.Synapses are the junction of signal inputs for neurons. Dendrites possess both excitatory as well as inhibitory synapses.Microtubule polarity in the dendrite is different from the axon polarity. Microtubules form the railway track or information track for the transmission of the signals along the dendrite’s length. The cytoskeleton structure of dendrites is made up of actin filaments, neurofilaments, and microtubules (long and thin structures having 24 nm diameter and having a longitudinal orientation towards the axis of the dendrite). The smooth endoplasmic reticulum is found throughout the dendrite structure and is responsible for the calcium ion regulation in the dendrite. Dendrites contain various cytoskeletal elements, Golgi bodies, smooth endoplasmic reticulum, and ribosomes.Dendrites receive the electrochemical signals.Distal dendrites can have multiple shapes, mushroom-shaped, cup-shaped, tapering, etc.Each dendrite is about 2 µm long and usually 5 – 7 dendrites are present and usually form a complex interwoven structure near the neuron which is referred to as a dendritic tree.Dendrites are shorter structures that taper off towards the ends.Dendrites are an integral part of the mammalian central nervous system.Dendrites: Dendrites are the protoplasmic projections found at the terminal end of the neuron and they function to receive the cellular signals from the other neurons through neuronal synapse.Axons have voltage-gated Sodium ion channels that propagate the electrical signals along their length to reach the synapse. Axons function to send the electrochemical signals. Axons are longer than dendrites and have almost the same diameter throughout their length. It functions to carry information away from the cell body towards the axon terminals and eventually transmit it to another neuron. Axon: Axon is the single, protoplasmic tubular projection arising from the cell body of the neuron.Cell body: The cell body or soma is the nucleus of the neuron cell that contains, the endoplasmic reticulum, Golgi bodies, mitochondria, and other cellular components.All individual neurons have these three fundamental parts: While the motor neurons transmit the signals from the brain to the muscles. There are sensory neurons throughout the body that collect sensory stimuli from the sensory receptors of the body and send them to the brain to process them. Neurons are the building blocks of the nervous system, that receive the signals/information from one part of the body and transmit it to the other part of the body. Briefly, let us understand the structure of neurons.
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