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57 Cards in this Set
- Front
- Back
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Why are chemical senses the oldest senses?
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Back in the day we lived in an aqueous enviroment and the chemicals floated around in the enviroment.
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What is the dectection of food chemicals in our saliva?
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Gustation
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What is the detection of volatile chemicals in the air?
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Olfaction
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What enviroments do chemical receptors allow us to monitor?
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Both internal and external enviroments
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What classifications can taste and smell make in regards to a stimulus?
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1. Type
2. Quality 3. Pleasantness vs Unpleasantness vs Danger |
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According to Dr. Nelson, what chemical sense is often overlooked?
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A sense mediated by CN V that senses cold, hot and spicy.
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What are two important functions of taste?
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1. Mediates our appetite
2. Protects us from toxins |
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What are the five qualities of taste?
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1. Sweet
2. Sour 3. Bitter 4. Salty 5. Savory (proteins) |
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Savory is often described as being associated with what? More specifically?
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1. Protein
2. Glutamate |
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What are hedonistic descriptions of taste?
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Descriptions that describe how we perceive what we are tasting
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Which cranial nerves help innervate what parts of the taste bud distribution?
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1. CN VII - anterior portion of the tounge
2. CN IX - back of the tounge 3. CN X - the pharynx 4. Superior petrosal branch - palate |
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What nucleus do the signals from tastebuds end up at?
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Solitary nucleus
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Why is the current map of tasting on the tounge wrong?
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It implies you only taste a certain quality in a certain area, which is not true.
What is true is the fact that certain areas of the tounge have more receptors for a certain quality. |
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How many circumvallate papillae?
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Typically 10-12 on the back of the tounge
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What is the area that the microvilli associated with taste cells called?
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The taste pore
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How are taste cells categorized now-a-days?
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By their surface proteins
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What two surface proteins groups have a lot to do with how a taste cell is categorized?
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TR1 & TR2
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The signal transduction of taste can be divided up into what two groups?
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1. Ion channels
2. Receptor proteins |
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How does the salt ion channel work in regards to taste?
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1. Salt moves into the cell through an amiloride senstive (ENaC) channel.
2. This causes a build-up of salt in the cell which changes the membrane potential opening an amiloride insenstive channel. 3. This causes an overall transmembrane potential change (receptor potential) 4. This causes the release of NT |
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How do sour ion channels work?
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The high concentration of protons outside the cell cause the release of Cl- and the blockage of K movement. This combination depolarizes the cell and signals for NT release.
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What qualities of taste are related to G protein coupled receptors?
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1. Sweet
2. Bitter 3. Savory |
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What is the G protein used in taste?
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Gustducin
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Which receptor protein is used for each G protein coupled taste? What kind of sidechains do they have?
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1. Sweet - TR1 - Large carbohydrate
2. Umami - mGlu4 - Large carbohydrate 3. Bitter - TR2 - No large carbohydrate |
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What two categories can sweet be divided into? What is special about their taste pathways?
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1. Natural sugars
2. Sweetners (amino acid derivatives) 3. They have two different 2nd messanger pathways |
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What do natural sugar receptors activate?
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Adenylate cyclase
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What do sweetners activate?
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IP3 pathways
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What are the two transduction methods for bitter tasting items?
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1. K related pathway
2. Pathway that uses IP3 for large molecules (only one that uses internal calcuim stores) |
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What taste pathway is the only one that uses interal calcium stors?
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Bitter pathway for large molecules
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What type of signaling does umami use?
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Adenylate cyclase
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What does it mean that taste receptors have a best stimulus?
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Even thought they accept a broad range of stimuli, there is a particular stimuli that they like the best.
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Can nerves have a certain stimulus type that they like respond to better?
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Yes they do, this goes right along with the idea of best stimulus for the receptor.
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What can happen if you pair Na with another anion besides Cl?
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It will change the perception of its taste. It might seem sweet instead of salty.
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What do H neurons respond best to? N neurons? S neurons?
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1. Acid (sour)
2. Salt 3. Sweetners |
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What are the two theories of neural taste coding?
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1. Neural lines
2. Cross-fiber patterning |
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Explain the labeled line theory of neural coding.
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Basically everything from the taste cell to the cortical neuron is specific to a certain taste (ie banana)
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Explain the cross-fiber patterning theory of neural coding.
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Basically every taste item interacts with a certain combination of sweet, salty, bitter, savory and sour taste cells. All this information is presented to the cortex and it is processed as belonging to that food item. (ie banana)
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What does central taste include?
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1. NTS
2. Relay in the thalamus 3. Insular cortex |
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What type of stroke could wipe out some of one's ability to taste?
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Supratemporal stroke
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What chemical is used to determine whether someone is a supertaster? How is the ability inherited? If you are a supertaster, what type of treatment could cause you to become more nauseated than others?
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1. N-propylthiouracil (PROP)
2. Dominant gene 3. Chemotherapy |
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What is a smell?
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The combination of odor molecules
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How would one describe the typical odor molecule?
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Small, lipid soluble - acid, alcohol or ester
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How large is a human's olfactory area?
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Small - 5 square cm
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Describe how a odor molecule causes a smell.
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1. The odor molecule becomes dissolved in a mucous-like layer on the epithelium
2. Odorant binding proteins bind to the odor moecules and present them to cilia with odorant receptors 3. Signals are then sent via the olfactory nerve |
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What type of neurons are used for smell?
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Bipolar neurons
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What type of cell does the bipolar neuron for smell synapse on and where?
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1. Mitral cell
2. Olfactory bulb |
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Each olfactory receptor neuron contains how many types of odorant receptors?
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One
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How many odorants can a single odorant receptor recognize?
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Many, as long as they are similar in structure
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Is there such a thing called a smell map?
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No
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How many odor receptors do humans have?
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400
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Do odorant receptor neurons use secondary messanger systems?
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yes
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In olfaction, cAMP will activate what? What does this result in?
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1. Ion channels that are sensitive Ca and Na
2. Receptor potentials |
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What is the ratio of the number of neurons to one mitral cell glomeruli?
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1000:1
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What type of cells process the information transferred from the olfactory neurons(2)?
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1. Granular cells
2. Periglomerular cells |
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In olfaction, where is mapping very precise?
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On the olfactory bulb
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What is one distinction of the olfactory system that is different than all of the other senses?
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Part of the signals heading to the cortex don't ever go through the thalamus.
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If an olfactory signal does not go to the thalamus, where can it go instead?
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1. Other olfactory bulb
2. Hippocampus 3. Pyriform complex of the amyglala |
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What is smell very closely related to?
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Memory
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