17_LectureOutline

17_LectureOutline - An Introduction to the Special Senses...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
An Introduction to the Special Senses Five Special Senses Olfaction * Gustation * Vision * Equilibrium * Hearing Smell (Olfaction) Olfactory Organs Provide sense of smell * Located in nasal cavity on either side of nasal septum * Made up of two layers * Olfactory epithelium * Lamina propria * Layers of olfactory organs * Olfactory epithelium contains *Olfactory receptors *Supporting cells *Basal (stem) cells * Lamina propria contains *Areolar tissue *Blood vessels *Nerves *Olfactory glands * Olfactory Glands * Secretions coat surfaces of olfactory organs * Olfactory Receptors * Highly modified neurons * Olfactory reception *Involves detecting dissolved chemicals as they interact with odorant-binding proteins * Olfactory Pathways * Axons leaving olfactory epithelium *Collect into 20 or more bundles *Penetrate cribriform plate of ethmoid *Reach olfactory bulbs of cerebrum where first synapse occurs *Axons leaving olfactory bulb: –travel along olfactory tract to reach olfactory cortex, hypothalamus, and portions of limbic system Arriving information reaches information centers without first synapsing in thalamus * \Olfactory Discrimination * Can distinguish thousands of chemical stimuli
Background image of page 1

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

View Full DocumentRight Arrow Icon
* CNS interprets smells by the pattern of receptor activity * Olfactory Receptor Population * Considerable turnover * Number of olfactory receptors declines with age Taste (Gustation) * Gustation provides information about the foods and liquids consumed * Taste receptors (or gustatory receptors) are distributed on tongue and portions of pharynx and larynx * Clustered into taste buds * Taste buds * Associated with epithelial projections (lingual papillae) on superior surface of tongue * Three types of lingual papillae *Filiform papillae: *provide friction *do not contain taste buds *Fungiform papillae: *contain five taste buds each *Circumvallate papillae: *contain 100 taste buds each * Taste buds contain * Basal (stem) cells * Gustatory cells *Extend taste hairs through taste pore *Survive only 10 days before replacement * Monitored by cranial nerves that synapse within solitary nucleus of medulla oblongata, then on to thalamus and primary sensory cortex Gustatory Discrimination Primary taste sensations * Sweet * Salty * Sour * Bitter * Additional human taste sensations * Umami *Characteristic of beef/chicken broths and Parmesan cheese *Receptors sensitive to amino acids, small peptides, and nucleotides * Water *Detected by water receptors in the pharynx * Dissolved chemicals contact taste hairs * Bind to receptor proteins of gustatory cell * Salt and sour receptors
Background image of page 2
*Chemically gated ion channels *Stimulation produces depolarization of cell * Sweet, bitter, and umami stimuli *G proteins: * gustducins End Result of Taste Receptor Stimulation Release of neurotransmitters by receptor cell Dendrites of sensory afferents wrapped by receptor membrane * Neurotransmitters generate action potentials in afferent fiber * Taste Sensitivity
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/29/2011 for the course BIOLOGY 24011 taught by Professor Pan during the Fall '11 term at HCCS.

Page1 / 12

17_LectureOutline - An Introduction to the Special Senses...

This preview shows document pages 1 - 4. Sign up to view the full document.

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