Chemical synapse

Electrical and chemical synapses serve different functions in the nervous system, and the use of each type of synapse has advantages and disadvantages for situations requiring signal transmission. One of the advantages of the use of an electrical synapse is speed, as electrical synapses allow action potentials to pass directly from neuron to neuron through the use of gap junctions. This direct passage and resulting speed of transmission isn’t present in chemical synapses. Chemical synapses rely on the transformation of the action potential into a chemical called the neurotransmitter, which is diffused across the synapse to bind to receptors in another neuron and then transformed into another action potential to continue the signal transmission…

The synapse consists of a pre-synaptic terminal, the synaptic cleft and a post-synaptic terminal. The pre-synaptic axon terminal is separated from the post-synaptic membrane of another cell’s dendrite by a narrow synaptic cleft, a distance of 20 to 30 nanometers across (1). Fig. 2-2 illustrates the series of events that occur at the synapse. At the synapse, the axons form the information-delivering terminal. The axon terminal contains tiny spherical structures called synaptic vesicles. APs…

Short-term plasticity at the ORN  PN synapse could result in PN responses that are strongest during the rising phase of the ORN response since the ORN  PN synapses display short-term depression that causes ORN spikes that arrive later to produce smaller postsynaptic potentials than the ones produced by earlier spikes. In depressing synapses, successive action potentials result in smaller and smaller postsynaptic responses. The reduction in postsynaptic responses could be due to smaller amount…

When this sodium reaches the terminal buttons, calcium enters the cell and causing vesicles to bind to the cell wall and release the content that is present, usually a neurotransmitter. This neurotransmitter will now go to a different neuron, and incite an action potential. This whole process occurs all the time will billions of neurons. It is an exceedingly complex system that is vital for the survival of species. What if the sodium channels were blocked when there is an impulse or stimulus…

1.3.4 Cell-Cell Communication in Taste Buds: Activation of Type II cells by taste stimuli causes release of ATP through pannexin hemichannels and/or CALMH1 channels. The released ATP or sour stimuli can activate Type III cells and causes release of different hormones such as 5-HT and NE via Ca2+-dependent exocytosis. In some instances NE is co-released with 5-HT (Dvoryanchikov et al., 2007; Huang et al., 2008a). The ATP released by Type II taste cells acts as a paracrine as well as an…

Sydney Holst When certain chemicals interact with a neuron, they alter the balance of ions inside and outside the cell. If this change reaches threshold, it sends a signal down the neuron’s membrane to the axon. At the axon, the neuron fires the signal to a neighboring neuron, and the process repeats. Once the electrical potential of Neuron A (presynaptic neuron) reaches -60mV the sodium and potassium channels in the neuron open at the beginning of the axon. The influx of positive sodium ions…

dysfunction of synaptic mitochondria in comparison with non-synaptic mitochondria. The second paper described the relation between the levels of insulin degrading enzyme (IDE), Aβ clearance enzyme and Aβ Amyloidogenesis, suggesting that clearance have a greater role in Aβ accumulation than APP production. BODY The neuron structure consists of extensions called dendrites that are the ones receiving the signals from other neurons and then transfer those signals through the axon. At the end of the…

Nociception After the initial insult, peripheral nociceptors are activated by transduction through thin myelinated Aδ and unmyelinated C-fibers to the dorsal root group and into the posterior horn of the spinal cord. The axon bifurcates into two branches with one branch continuing to the CNS, the other innervating peripheral tissues. Action potentials are generated and the nociceptive signals initiate excitatory neurotransmitters such as glutamate and substance P, neuromodulators including…

Neurotransmitters are proteins produced by the nervous system. To be classified as a neurotransmitter, a chemical must bridge the synapse and induce an electric current in a dendrite. Neurotransmitters may either excite the dendrite or inhibit it, and the same neurotransmitter may be excitatory or inhibitory in different neural circuits. Neurotransmitters that increase activity in the neuron are said to be excitatory. In contrast, neurotransmitters that decrease activity in the neuron are said…

with an organism. The enzyme catalyzes a specific set of chemical reactions. Enzymes are specific for the substrate and the reaction. The specificity of enzymes depends on the characteristics of the active site; it is where it binds to the substrate before the substrate transformations begin. Hormone specificity on the other hand, are cells that have specific membrane receptors to which hormones can bind. They can change their sensitivity to a hormone by changing the number or receptors.…