China
Africa
Explore chapters and articles related to this topic
Introduction to botulinum toxin
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
Neurons are made of a cell body, dendrites and an axon. Their basic function is to transmit electrical signals, or nerve impulses, from one part of the body to another. Due to the speed of electrical transmission, they are able to transfer information between cells incredibly quickly. The cell body of a neuron is where the nucleus is located, as well as organelles important in keeping the nerve cell alive such as the Golgi apparatus and mitochondria. Attached to the cell body are dendrites which receive neuronal impulses. Once an impulse is received, the cell body can then decide whether to transmit, propagate or dismiss an impulse, and one of the key determinants on which outcome occurs is the strength of the signal itself.
The patient with acute neurological problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
The neurone cell body is similar to other cells and contains a nucleus with a prominent nucleolus, mitochondria, Golgi apparatus, free ribosomes and rough and smooth endoplasmic reticulum and lysosomes, all surrounded by cytoplasm and contained by a cell membrane. Neurones synthesise vast amounts of protein to maintain cell membrane proteins, intracellular organelles and neurotransmitters and to support the neural processes that extend from the cell body. Protein is synthesised by large numbers of free ribosomes and rough endoplasmic reticulum called Nissl bodies or granules.
Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
In the case of living cells, an important deduction can be made concerning the magnitude of the charge needed to establish the voltage difference involved. Consider a small neuron whose cell body can be approximated as a sphere of diameter d µm. Let the voltage across the cell membrane be 70 mV and the membrane capacitance be 1 µF/cm2 (Section 2.2). The charge in coulombs (C) across the cell membrane associated with the 70 mV transmembrane voltage is (70 × 10−3 V)×(1 µF/cm2) × π×(10−4d cm)2 = 7 × 10−16πd2 C ≅ 2.2 × 10−15d2 C. If we consider the concentration of K+ alone inside the cell to be about 150 mM, or 0.15 moles/liter, the charge due to K+ inside the cell is 0.15 × 96,485 × 10−3×(π/6)×(10−4d cm)3 ≅ 7.6 × 10−12d3 C. The ratio of the charge associated with the 70 mV transmembrane voltage to the charge of K+ alone inside the cell is 2.9 × 10−4/d. Even if d = 1 µm, this ratio is only about 0.03%. It can be concluded, therefore, that the quantity of charge needed to establish the voltage difference across biological membranes is very small compared to the charge of either polarity that is present on the two sides of the membrane.
Efficient simulations of stretch growth axon based on improved HH model
Published in Neurological Research, 2023
Xiao Li, Xianxin Dong, Xikai Tu, Hailong Huang
Neuronal cell is composed of three components: a cell body, an axon, and a dendrite. These components are responsible for receiving, integrating, and delivering information. In general, neurons receive and integrate information from other neurons via their dendrites and cell bodies, and then transfer it to other neurons via their axons. Nerve fibers have great excitability and conductivity, and their primary role is to transmit information between neurons. When a sufficient stimulus excites a nerve fiber, it immediately generates a propagable action potential. Chemical synapses allow action potentials to be passed from one neuron to the next by transporting neurotransmitters through synaptic vesicles. The action potential-induced shift in membrane potential causes the calcium channel on the synaptic terminal membrane to open, allowing a substantial number of calcium ions to flow into the membrane, resulting in an abrupt increase in calcium ions in the synaptic membrane. When synaptic vesicles detect an increase in the number of calcium ions in the surrounding environment, they fuse with the presynaptic membrane and spit neurotransmitters into the synaptic gap. After binding to a protein receptor on the postsynaptic membrane, the neurotransmitter causes excitement or inhibition.
Prediction of abrasive wears behavior of dental composites using an artificial neural network
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Abhijeet Shivaji Suryawanshi, Niranjana Behera
The human brain is composed of billions of interconnected neurons by an unbelievable number of connections. Each neuron is linked to several other neurons and communicates with them regularly. So any physical or mental activity, we engage in activates a certain group of neurons in our brains. Figure 1(a) describes the structure of neuron in a brain. A single neuron is made up of three parts: (1) dendrites, (2) cell body, and (3) terminals. An artificial neuron, seen in Figure 1(b), is a computational and mathematical model of a biological neuron. Figure 1(c) shows the architecture of a neural network having input p, output a, and feeding with r and s parameters. Other parameters of a neural network are bias vector b, weight matrices w, transfer function f, and linear combiner u (Maleki and Unal 2021).
Dose-dependent long-term effects of a single radiation event on behaviour and glial cells
Published in International Journal of Radiation Biology, 2021
Marie-Claire Ung, Lillian Garrett, Claudia Dalke, Valentin Leitner, Daniel Dragosa, Daniela Hladik, Frauke Neff, Florian Wagner, Horst Zitzelsberger, Gregor Miller, Martin Hrabĕ de Angelis, Ute Rößler, Daniela Vogt Weisenhorn, Wolfgang Wurst, Jochen Graw, Sabine M. Hölter
The analysis of the morphology of the Iba1+ and GFAP + cells was done with a Zeiss Axio Imager M2 microscope (Carl Zeiss, Oberkochen, Germany) with a motorized stage and a CCD colour camera. The software used was Neurolucida Version 2018 and Neurolucida Explorer 2018 (MBF biosciences, Williston, VT, USA). Using the 100x objective, 10 microglial cells and 10 astrocytes per animal were traced. This cell sample size was deemed appropriate for this analysis as it has been shown previously to be reliable for microglial morphometry (Fernandez-Arjona et al. 2017) and the coefficient of variation, indexing the precision accuracy for morphological parameters of each animal cell population (standard deviation/mean), was less than 1. We focused only on the infra-pyramidal region of the dentate gyrus for both analyses where clearly stained and non-overlapping cells were visible to trace completely and to minimise the potential confounding influence of sub-region-specific differences in microglial morphology. The cell body of each selected cell was contoured in the Neurolucida program at the z-stage-level where it showed the biggest area in focus. The branches were traced in 3D focusing through the z-plane. The traced 3D-cell structures were analysed in Neurolucida Explorer using Sholl Analysis (radius 5 µm) and the Branched Structure Analysis function. The parameters measured to gauge branching complexity for each microglial cell and astrocyte were number of nodes (where bifurcations or trifurcations occur), intersections, endings and branch length.