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Esdin LS 2 Lec 4 Sensory

Cilium stereocilia kinocilium stretch gated channels

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Unformatted text preview: top Basilar membrane Axons To auditory nerve very flexible 5 4/21/13 Hair Cell one stiff cilium Stereocilia Kinocilium Stretch gated channels hair cells release neurotransmitters forms synapses, hair cell + neuron Sensory neuron Hair Cell Tectorial membrane Stereocilia Hair cell Basilar membrane Cochlear nerve bending causes stretch gated channels to open 6 4/21/13 K+ depolarizes here in Act. Pot. repolarizes influx of K+ leads to depolarization Hair Cells At Rest Protein bridge K+ K+ K+ all the cilia moving in the same direction has to be in a sp. direction for gates to open K+ Stretch gated channels gradient potential: small wave but not called that, receptor potential small wave of depolarization no action potential opened by physical stretching Ca2+ NT Voltage gated calcium channels Hair Cells Depolarized K+ K+ K+ K+ movement towards K-cilium results in depolarization Stretch gated channels Protein bridge Ca2+ decides if the aggregate input is enough to fire an action potential; will send the APs down the auditory nerve Voltage gated Ca2+ calcium channels Ca2+ NT fuses w membrane, and released NT signals travel to the temporal lobe activated and mobilization of neurotransmitters occurs auditory nerve --> medulla --> thalamus --> auditory cortex 7 4/21/13 Hair Cells Hyperpolarized K+ K+ K+ K+ Stretch gated channels Protein bridge Voltage gated calcium channels NT Hair Cells •  When hair cells are stimulated, K+ influx occurs •  The depolarization leads to the activation of the voltage-gated Ca channels •  Ca2+ influx causes the release of glutamate which activates the afferent neurons 8 4/21/13 Hair Cells •  Movement of the stereocilia towards the kinocilium activates the stretch activated channels •  Movement of the stereocilia away from the kinocilium closes the stretch activated channels Neural Pathway of Hearing •  Cochlear nerve fibers synapse on neurons in the cochlear nuclei in the medulla oblongata medial geniculate nucleus •  The signal is then sent to the thalamus •  From the thalamus, the information travels to the auditory cortex of the temporal lobe 9 4/21/13 The Eyes •  Composed of an optical portion •  Focus the image on sensory cells •  Transform the image to the brain through series of action potential •  Have receptors that are sensitive to light photoreceptors Layers of the Eyes Fibrous Neural inner outer Vascular middle light needs to fall on neural layer to be able to...
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