108733
Description
Flashcards by tanitia.dooley, updated more than 1 year ago
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Created by tanitia.dooley
almost 11 years ago
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| Question | Answer |
| Which sense does not go through the thalamus and instead goes straight to the sensory cortex | smell |
| What happens once compounds are dissolved in the mucous in smell? | they interact with odorant binding proteins which activates conversion of ATP into cAMP by adenylate cyclase-cAMP opens Na channels=depolarisation=AP to olfactory cortex |
| Is the smell pathway divergent or convergent? | convergent- nerve fibres come together which ampified the signal |
| How do we become adapted to a persistant smell? | central inhibition |
| Describe the smell pathway | olfactory bulb>olfactory tract > olfactory cortex> hypothalamus, limbic system |
| Describe discrimination in smell | receptor popns have distinct sensitivities- CNS translates each smell in accordance with the pattern of activity |
| How does ageing affect smell? | no. of receptors decline with age, cilia become damaged and dont get replaced, receptors become insensitive |
| How are olfactory receptors replaced? | basal cells proliferate and differentiate into new receptors |
| Describe the taste pathway | taste buds are montiored by the facial cranial nerve, glossopharabgyeal nerve (circumvillate) and vagus nerve (epiglottis) then goes to solitary nucleus then to thalamus and then to the sensory cortex |
| What are gustatory cells? | present on taste buds- each has ~40- found recessed into epithelium and have mirovilli hair qhich project through taste pore |
| How long do gustatory cells last? | ~10 days and then they are replaced |
| Where are taste buds found in adults and children? | superficial surface of tongue but also in pharynx and larynx in children |
| How many taste buds do we have? | 3000 |
| What is the circumvillate? | has ~100 taste buds each. V formation at the back of the tongue- most conc'd region of taste buds |
| What is the filiform? | friction, no taste buds |
| What is fungiform? | shaped like a mushroom, ~5 taste buds each-limited |
| We have quicker responses to what tastes? Why? | unpleasant ones: ~1000 times more sensitive to acids than sweet or salty and ~100 times more sensitive to bitter than acids- protective mech |
| How do we descriminate between different tastes? | chemicals contact the taste hair cell and bind to receptors- different tastes have different mechs e.g. salt receptors open Na channels, sweet close K+ channels |
| Which normal inhalations, how much inhaled air gets to olfactory organs? | ~2% |
| What is the mechanism from breathing in? | air swirls around in nasal cavities- turbulence delivers airborne particles to hair cells |
| Describe olfactory receptors and the cilia and explain why it is like that | multiple cilia to increase SA, exposed tip of each receptor cell called a nob- base for ~20 cells to icrease SA more. Cillia are within the mucous=increaaed SA and protection |
| What is mucous secreted by in smell? | bowmans gland |
| What must compounds be to diffuse into the mucous for smell? Why? | lipid and water soluble detected quicker and at lower conchs |
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