ch16ppt - 16-1Chapter 16The Special SensesSmell, taste,...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 16-1Chapter 16The Special SensesSmell, taste, vision, hearing and equilibriumHoused in complex sensory organs Ophthalmology is science of the eyeOtolaryngology is science of the ear16-2Chemical SensesInteraction of molecules with receptor cellsOlfaction (smell) and gustation (taste)Both project to cerebral cortex & limbic systemevokes strong emotional reactions16-3Olfactory Epithelium1 square inch of membrane holding 10-100 million receptorsCovers superior nasal cavity and cribriform plate3 types of receptor cells16-4Cells of the Olfactory MembraneOlfactory receptorsbipolar neurons with cilia or olfactory hairsSupporting cells columnar epitheliumBasal cells = stem cellsreplace receptors monthlyOlfactory glandsproduce mucusBoth epithelium & glands innervated cranial nerve VII.16-5Olfaction: Sense of SmellOdorants bind to receptorsNa+ channels openDepolarization occursNerve impulse is triggered16-6Adaptation & Odor ThresholdsAdaptation = decreasing sensitivityOlfactory adaptation is rapid50% in 1 secondcomplete in 1 minuteLow thresholdonly a few molecules need to be presentmethyl mercaptan added to natural gas as warning16-7Olfactory PathwayAxons from olfactory receptors form the olfactory nerves (Cranial nerve I) that synapse in the olfactory bulbpass through 40 foramina in cribriform plateSecond-order neurons within the olfactory bulb form the olfactory tract that synapses on primary olfactory area of temporal lobe conscious awareness of smell beginsOther pathways lead to the frontal lobe (Brodmann area 11) where identification of the odor occurs16-8Gustatory Sensation: TasteTaste requires dissolving of substancesFour classes of stimuli--sour, bitter, sweet, and salty10,000 taste buds found on tongue, soft palate & larynxFound on sides of circumvallate & fungiform papillae3 cell types: supporting, receptor & basal cells16-9Anatomy of Taste BudsAn oval body consisting of 50 receptor cells surrounded by supporting cellsA single gustatory hair projects upward through the taste poreBasal cells develop into new receptor cells every 10 days.16-10Physiology of TasteComplete adaptation in 1 to 5 minutesThresholds for tastes vary among the 4 primary tastesmost sensitive to bitter (poisons)least sensitive to salty and sweetMechanismdissolved substance contacts gustatory hairsreceptor potential results in neurotransmitter releasenerve impulse formed in 1st-order neuron16-11Gustatory PathwayFirst-order gustatory fibers found in cranial nervesVII (facial) serves anterior 2/3 of tongueIX (glossopharyngeal) serves posterior 1/3 of tongueX (vagus) serves palate & epiglottisSignals travel to thalamus or limbic system & hypothalamusTaste fibers extend from the thalamus to the primary gustatory area on parietal lobe of the cerebral cortexproviding conscious perception of taste16-12Accessory Structures of Eye...
View Full Document

This note was uploaded on 05/23/2010 for the course BIO 222 taught by Professor Brooks during the Spring '10 term at Prairie State College .

Page1 / 76

ch16ppt - 16-1Chapter 16The Special SensesSmell, taste,...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online