Senses and Sensibility I. Sensory modalities II. Physiology of sensation III. Thermal homeostasis IV. Physiology of taste Physiology of smell
Sensory Modalities Chemoreceptors (e.g., taste, smell, O2 level in blood)
Sensory Modalities Chemoreceptors Mechanoreceptors (e.g., taste, smell, O2 level in blood) Mechanoreceptors (e.g., touch, hearing, equilibrium, proprioreception)
Sensory Modalities Chemoreceptors Mechanoreceptors Photoreceptors (e.g., taste, smell, O2 level in blood) Mechanoreceptors (e.g., touch, hearing, equilibrium, proprioreception) Photoreceptors (vision, photoperiod)
Sensory Modalities Chemoreceptors Mechanoreceptors Photoreceptors (e.g., taste, smell, O2 level in blood) Mechanoreceptors (e.g., touch, hearing, equilibrium, proprioreception) Photoreceptors (vision, photoperiod) Thermoreceptors
Communication by Sensory Neurons Axon Hillock Sensory stimuli cause graded potentials
Communication by Sensory Neurons Axon Hillock Sensory stimuli cause graded potentials AP triggered in sensory neuron if graded potentials reach threshold
Communication by Sensory Neurons Axon Hillock Sensory stimuli cause graded potentials AP triggered in sensory neuron if graded potentials reach threshold Sensory neurons synapse onto neurons of CNS
Properties of Sensory Neurons Selectivity Hearing Taste Vision
Properties of Sensory Neurons Selectivity Transduction convert stimulus into graded potential Na+ channels open or close AP created in sensory neuron
Senses and Sensibility I. Sensory modalities II. Physiology of sensation III. Thermal homeostasis IV. Physiology of taste Physiology of smell
Range of Sensory Perception Sensory Adaptation Thalamus filters out some stimuli
Range of Sensory Perception Range Fractionation - neurons differ in range of sensitivity
Senses and Sensibility I. Sensory modalities II. Physiology of sensation III. Thermal homeostasis IV. Physiology of taste Physiology of smell
Thermoreceptors Peripheral Thermoreceptors Central Thermoreceptors - epithelial tissue Central Thermoreceptors - hypothalamus
Thermal Homeostasis Stimulus: Cold Air Stimulus: High Core Temp Peripheral Thermoreceptor Central Hypothalamus Motor Neuron Muscle (Shivering) Sympathetic NS Sweat Glands
Senses and Sensibility I. Sensory modalities II. Physiology of sensation III. Thermal homeostasis IV. Physiology of taste Physiology of smell
Chemoreceptors Chemoreceptors respond to chemicals in an aqueous solution The Chemical Senses: Taste 5 receptor types cells are highly generalized
Taste Buds are Located in Papillae
Taste Buds are Located in Papillae Gene Simmons has LOTS of papillae!
Taste Buds are Located in Papillae Taste buds line the papillae of your tongue.
Taste Buds are Located in Papillae Taste buds line the papillae of your tongue. I Rock & Roll all Night and Party Every Day!
Anatomy of Taste Buds Taste cell Support cell Basal cell
Anatomy of Taste Buds Taste cell Support cell Basal cell 1) Taste cells form receptor surface and synapse with cranial nerves
Anatomy of Taste Buds Taste cell Support cell Basal cell 1) Taste cells form receptor surface and synapse with cranial nerves 2) Supporting cells provide support for taste buds
Anatomy of Taste Buds Taste cell Support cell Basal cell 1) Taste cells form receptor surface and synapse with cranial nerves 2) Supporting cells provide support for taste buds 3) Basal cells produce new _________
Hypothetical Distribution of Taste Cells
Hypothetical Distribution of Taste Cells
Distribution of Taste Taste cell Support cell Basal cell Most taste cells respond to only 1 of the 5 tastes
Transduction in Taste Cells Salty & Sour flavors - Na+ or H+ ions enter cells through existing channels
Transduction in Taste Cells Sweet , Bitter & Umami more complicated Bind to receptors and activate secondary messengers, which open Na+ channels
Senses and Sensibility I. Sensory modalities II. Physiology of sensation III. Thermal homeostasis IV. Physiology of taste Physiology of smell
Jerry made the ice cream but Ben would test all the new flavors because Ben has hardly any sense of smell JERRY GREENFIELD: He kept making me put in these bigger and bigger pieces of chunks. BEN COHEN: Jerry always wanted to make them smaller so that there would be better chunk distribution in each scoop, or in each pint, and I insisted that it was critical that the chunks be really, really huge. And he said, “but Ben, somebody might take a spoonful and they won't get a chunk at all.” And I said, “that's OK, that's a sacrifice you have to make. It's worth it, for the big chunk they'll get in the next spoon.”
Olfaction (Smell) Smell enhances the sense of Taste
Olfaction (Smell) Smell enhances the sense of Taste
Olfaction (Smell) Smell enhances the sense of Taste
Olfaction (Smell) Smell enhances the sense of Taste Olfactory cells
Olfaction (Smell) Smell enhances the sense of Taste Olfactory cells Mucus
Anatomy of Olfaction Olfactory nerve olfactory bulb Ethmoid olfactory epithelium basal cell olfactory cell support cell
Chemoreceptors Chemoreceptors respond to chemicals in an aqueous solution The Chemical Senses: Taste 5 receptor types cells are highly generalized Smell Thousands of receptor types cells are highly specialized
Olfactory Cells Are Specialists The nose can distinguish ~10,000 odors
Olfactory Cells Are Specialists The nose can distinguish ~10,000 odors 10,000 Odors! How does your nose knows?
Olfactory Cells Are Specialists Nose can distinguish ~10,000 odors! Each olfactory cell expresses a different receptor protein (only one type per cell)
Olfactory Cells Are Specialists Nose can distinguish ~10,000 odors! Each olfactory cell expresses a different receptor protein (only one type per cell) Cells with a given receptor are randomly distributed in the olfactory epithelium
Olfactory Cells Are Specialists Nose can distinguish ~10,000 odors! Each olfactory cell expresses a different receptor protein (only one type per cell) Cells with a given receptor are randomly distributed in the olfactory epithelium All neurons of a given type converge in the olfactory bulbs of the brain
point of convergence (in olfactory bulb) Convergence of Olfactory Cells nasal epithelium Ethmoid Bone
Physiology of Olfaction Volatile odor enters nasal cavity
Physiology of Olfaction Volatile odor enters nasal cavity
Physiology of Olfaction Volatile odor enters nasal cavity Odor dissolves in mucus lining
Physiology of Olfaction Volatile odor enters nasal cavity Odor dissolves in mucus lining Bind to receptor protein
Physiology of Olfaction Volatile odor enters nasal cavity Odor dissolves in mucus lining Bind to receptor protein Na+ channels open
Physiology of Olfaction Volatile odor enters nasal cavity Odor dissolves in mucus lining Bind to receptor protein Na+ channels open AP sent to Olfactory Bulb
Physiology of Olfaction Volatile odor enters nasal cavity Odor dissolves in mucus lining Bind to receptor protein Na+ channels open AP sent to Olfactory Bulb To the Brain
Hmmm… That smells like bacon
The Dirty Secret Behind Flavor So why do McDonald’s fries taste soooooo good?
New Jersey Smells Great! McDonalds French Fries: Potatoes, partially hydrogenated soybean oil, natural flavor (beef, wheat and dairy sources), dextrose, sodium acid pyrophosphate (to preserve natural color). Cooked in partially hydrogenated vegetable oils (may contain partially hydrogenated soybean oil and/or partially hydrogenated corn oil and/or partially hydrogenated canola oil and/or cottonseed oil and/or sunflower oil and/or corn oil). Contains derivatives of wheat and dairy.