GE CLST 73A Lecture Notes - Lecture 11: Frontal Lobe, Olfactory Bulb, Afferent Nerve Fiber
1 Nov 2016
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Detects touch, pain, body position, & temperature. Pacinian corpuscle (pc): receptor for tactile stimuli: transduction in pc occurs when nerve membrane stretched, allowing na+ to pass. Dorsal column system (dc)- how touch info gets to brain. Axons for touch ascend in dorsal columns of spinal cord. Different amounts of somatosensory cortex devoted to different areas. Certain spots are more sensitive than others. (ex. Processes fluctuations in air pressure (sound waves) Vibrating objects generate sustained waves perceived as sound: waves very in amplitude: bigger=louder, frequency (hz) cycles per second: higher hz=higher pitched. External ear (pinna): shaped to collect sound waves: many animals can move pinnae to help capture sound. Cochlea: sensory organ: transduction takes place in hair cells (hair cells don"t grow back) Thin fibers=tip links -> run across each hair cell stereocillia: vibration makes stereocillia sway, causing ion channels to open allowing positive ions to enter, hair cell depolarizes & calcium influx @ base of cell causes nt release.
