Describe The Role Of Neurons In The Brain

At the molecular level of explanation these processes are dependent on the interplay between glutamate receptors, Ca2+ channels, the increase of intracellular Ca2+ levels, Ca2+-dependent proteins like Akt, ERK, mTOR and neurotrophins such as brain derived neurotrophic factor (BDNF) (24, 25).

Q1: The cerebral cortex is a highly organized, six layered structure (L1-6) with a variety of excitatory and inhibitory cell types. Excitatory (glutamatergic) neurons make up 80% of the cortex and consist of pyramidal and spiny stellate (granule) neurons. Inhibitory (GABAergic) neurons make up only 20% of the cortex and consist of four different subtypes: non-fast spiking serotonin expressing GABAergic neurons, martinotti cells, basket cells, and chandelier cells (Petersen & Crochet, 2013; Shipp, 2007). The total number of neuronal cells in the adult human cortex is 21.4 billion for females and 26.3 billion for males; however, there are also non-neuronal cells present in the cortex (Pelvig, Pakkenberg, Stark, & Pakkenberg, 2008). The major non-neuronal cells are glial cells and consist of: oligodendrocytes (75% of non-neuronal cells), astrocytes (20%) and microglia (5%) (Pelvig et al., 2008). The layering of the cortex is highly organized, with specific cell bodies located in each layer. Layer 1 receives input from other cortical layers as well as subcortical layers and is comprised solely of inhibitory neurons, although there are axons and dendrites that project onto these neurons in addition to non-neuronal cells (Petersen & Crochet, 2013). Layers 2/3 are difficult to differentiate from one another, and often referred to as the supragranular layers. These layers contain medium sized pyramidal cells that have densely packed and highly aligned apical dendrites and make

The purpose of this essay is to explain the mechanisms of neural communication, and the influence that different drugs have on this communication. The nervous system is made up of several cells that are called neurons, which are situated inside the Central Nervous System (Martin, Carlson & Buskit, 2013). Neurons comprise of three mechanisms, a cell body which is referred to as the soma, dendrites and an axon (Pinel, 2011).

The end of the axon spread into some shorter fibers that have swellings on the ends called synaptic knobs. The synaptic knob has a number of little saclike structures in it called synaptic vesicles. Inside the synaptic vesicles are chemicals hung in fluid, which are molecules of substances called neurotransmitters which are inside a neuron and are going to transmit a message. Neurotransmitter are released into the synapse from synaptic vesicles. The neurotransmitter molecules bind to receptor sites on the releasing neuron and the second neuron or glands or even muscles causing a reaction.

Glutamate-receptor-interacting protein (GRIP) is the interacting protein which is associated with AMPAR protein receptor in the postsynaptic cell. Amount of GRIP is associated with AMPAR receptors can lead to the prediction of activity in the presynaptic cell. AMPAR receptor change shape to be ready to receive neurotransmitter when GRIP bind. The presynaptic cell contains vesicle which neurotransmitters are accommodated. When calcium enters the presynaptic cell by calcium channel, vesicles dock to the presynaptic cell to become ready to release neurotransmitters to the synaptic gap. Neurotransmitters are released in a packet called quanta. AMPAR receptor has to change its shape by GRIP to receive the release of quanta in the synaptic

Neurotransmitters are chemicals made by neurons and used by them to transmit signals to the other neurons or non-neuronal cells (e.g., skeletal muscle; myocardium, pineal glandular cells) that they innervate. The neurotransmitters produce their effects by being released into synapses when their neuron of origin fires (i.e., becomes depolarized) and then attaching to receptors in the membrane of the post-synaptic cells. This causes changes in the fluxes of particular ions across that membrane, making cells more likely to become depolarized, if the neurotransmitter happens to be excitatory, or less likely if it is inhibitory.

Synapses are the basic structures underlying neurotransmission and brain function. Synapses are composed of a presynaptic neuron and a postsynoptic neuron which are separated by a synoptic cleft. Neurotransmitters are synthesized and packages into synaptic vesicles in the presynaptic neural terminal. In response to a nerve impulse, the vesicles are extruded into the synaptic cleft; approximately 1,000 molecules of neurotransmitter per terminal. The neurotransmitters then bind

An action potential is a short electrical impulse generated at the axon hillock which travels the length of an axon. Its generation happens in three distinct stages, depolarisation, repolarisation and hyperpolarisation. When the threshold of excitation is reached, depolarisation starts, the threshold is between -55mV and -65mV in most neurons. When the neuron is stimulated voltage-activated Sodium (Na+) channels open, allowing Na+ ions to rush into the neuron. This reverses the polarity in the neuron towards its peak of +40mV. At this peak Na+ channels

The brain is a unique organ, it allows us as humans, for example to imagine, speak and perform a lot more complex functions. To function well as a complex organ, the brain has a lot of cells. The brain consists of neurones and glia cells. Neurones observe changes from the environment, communicate these changes to other neurones and issue commands to the body to react on these changes. Glia cells give the neurones among other things protection and support. Neurones are really small cells composed of two parts: the soma, which contain the cell nucleus and neurites, which are projections from the soma. There are two different types of neurites, the axon and the dendrite. Dendrites receive signals to transfer to the neurones and axons carry the output of the neurones. Figure 1 gives a schematic overview of a neuron and shows the dendrites, cell body and axon. This essay will discuss the structure of neurones and the different types of neurones further in detail. It will start with the structure of a typical structure of a neuron and then the different types of neurones, the sensory-, motor- and interneurones. (Bear, M.F. et al. (2007))

In neuroscience it is assumed that the central nervous system governs and defines all aspects of behavior (Grobstein, 1998). Therefore, the brain, the hub of the central nervous system, is responsible for integrating all sensory and motor patterning. To understand the mechanisms of neurobiology it is often useful to observe the nervous system at the level of the neuron. Integration and communication between neurons is facilitated by neurotransmitters, chemicals which act as intermediaries at the synaptic gap (Delcomyn, 1998). Many behavioral disorders have a neurochemical basis, oftentimes associated with abnormal neurotransmitter activity. These abnormalities are thought to stem from

How AP firing of living neurons alters the electrochemical properties of CPs to release Glu will be investigated. The AP firing has a short duration (~5 ms) with a magnitude (amplitude) of 100 mV. Whole cell patch clamp electrophysiology techniques will be used. Neurons in contact with CP will be induced to fire action potential, triggering Glu release through current injections of 20-800 pA over 20-1000 ms (36, 73, 78). While one AP lasts ~5 ms, current injection to sustain AP firing can be routinely performed for 20 – 1000 ms to induce multiple AP if required (73). Fig. 7 shows the setup that has been designed to be compatible with the patch clamp apparatus and will be used in the experiment. As media flows through the setup, the media leaving will be quantified for Glu with an HPLC method. If AP firing is insufficient to cause Glu release, amplification methods will be applied to boost the triggering

As soon as the electrical signal reaches the end of the axon, mechanism of chemical alteration initiates. First, calcium ion spurt into the axon terminal, leading to the release of neurotransmitters “molecules released neurons which carries information to the adjacent cell”. Next, inside the axon terminal, neurotransmitter molecules are stored inside a membrane sac called vesicle. Finally, the neurotransmitter molecule is then discharged in synapse space to be delivered to post synaptic neuron.

In the brain there is an excitory and inhibitory input of neurotransmitters. GABA is the main inhibitory input of neurotransmitters and glutamate is the main excitory input of neurotransmitters. Glutamate transmits chemical signals from neuron to neuron. It is critical for learning and remembering. [1] Glutamate, as it is lethal in high concentrations to nerve cells, is stored in neurons as glutamine in order to keep the neurons healthy and to prevent the stimulation of seizures. [2] Glutamate is synthesised one of two ways, it can either be converted from glutamine to glutamate with the assistance of the enzyme glutaminase, or by transaminating 2-oxoglutarate. [3]

The brain is the hub of the human (Homo sapiens) body’s abilities, the control center of every bodily function. Brain cells, more formally known as neurons, are the brain’s way of communication. Neurons communicate by sending and receive a message from another neuron using axons and dendrites (PubMed Health). An axon is the thread like piece of the neuron that allows the conduction of electrical impulses to other nerve cells. At the end of the axon, the electrical signal is converted into a chemical signal, and the axon releases chemical messengers known as neurotransmitters. The neurotransmitters are released into the space between the end of an axon and the tip of a dendrite from another neuron. After travelling the short distance, the neurotransmitter

Neurotransmitters are chemical messengers involved in signalling and transmission of nerve impulses across the synapses. They pass into the synaptic cleft through the membranes of the synapses and travel to the opposite membrane initiating an electrical stimulus. Glutamic acid is a neurotransmitter that plays a principal role in neural activation within the brain. It is also responsible for the taste sensation referred to as ‘umami’ that is associated with certain