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The cochlear nerve (also auditory nerve or acoustic nerve) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes, the other part being the vestibular nerve. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear ...
Photosystem II (of cyanobacteria and green plants) is composed of around 20 subunits (depending on the organism) as well as other accessory, light-harvesting proteins. Each photosystem II contains at least 99 cofactors: 35 chlorophyll a, 12 beta-carotene , two pheophytin , two plastoquinone , two heme , one bicarbonate, 20 lipids, the Mn
Neurons whose cell bodies lie in the spiral ganglion are strung along the bony core of the cochlea, and send fibers into the central nervous system (CNS). These bipolar neurons are the first neurons in the auditory system to fire an action potential, and supply all of the brain's auditory input.
There are two types of hair cells specific to the auditory system; inner and outer hair cells. Inner hair cells are the mechanoreceptors for hearing: they transduce the vibration of sound into electrical activity in nerve fibers, which is transmitted to the brain. Outer hair cells are a motor structure.
The superior olivary complex is generally located in the pons, but in humans extends from the rostral medulla to the mid-pons [1] and receives projections predominantly from the anteroventral cochlear nucleus (AVCN) via the trapezoid body, although the posteroventral nucleus projects to the SOC via the intermediate acoustic stria.
In this way, the mechanical sound signal is converted into an electrical nerve signal. Repolarization of hair cells is done in a special manner. The perilymph in the scala tympani has a very low concentration of positive ions. The electrochemical gradient makes the positive ions flow through channels to the perilymph. Hair cells chronically ...
Photosystem II is present on the thylakoid membranes inside chloroplasts, the site of photosynthesis in green plants. [9] The structure of Photosystem II is remarkably similar to the bacterial reaction center, and it is theorized that they share a common ancestor. The core of Photosystem II consists of two subunits referred to as D1 and D2 ...
The release of neurotransmitter at a ribbon synapse, in turn, generates an action potential in the connected auditory-nerve fiber. [7] Hyperpolarization of the hair cell, which occurs when potassium leaves the cell, is also important, as it stops the influx of calcium and therefore stops the fusion of vesicles at the ribbon synapses.