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41 Cards in this Set
- Front
- Back
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What is the function of chemosensation?
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Detects whether something is beneficial or harmful without ingesting
Social - sexual partners Defence - territory and predators |
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What must odour molecules be in order for us to smell them?
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Small and volatile enough to vaporise, reach nose and dissolve in the mucus
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Do the receptors for olfaction relay in the thalamus?
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No, no neocortex area for olfaction
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Do olfactory pathways cross over?
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nope
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What are the olfactory receptors called?
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Olfactory receptor neurons
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What 3 types of cell make up the olfactory epithelium?
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Olfactory receptor cells
Basal cells Columnar supporting cells |
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Which cells produce the mucus covering the epithelium?
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Bowman's glands
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What is contained within the mucus?
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Mucopolysaccharides, enzymes, immunoglobulins, proteins
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Why do dogs have wet noses?
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To wash away odours in order to pick up new ones
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Why is mucus yellow in humans?
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Due to pigmented epithelial cell
Dark yellow or brown in dogs |
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What are odorant-binding proteins?
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Proteins that bind to odour molecules in order to facilitate their transfer to odour receptor cells
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How often are olfactory receptor neurons replaced?
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Every 4-8 weeks
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Where are the receptors found in the olfactory cell?
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On the cilia there is a G-protein receptor - sperm have olfactory receptor - can they smell egg? ew
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How many types of receptor protein does each neuron express?
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Only one
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What are the 4 parts of the olfactory receptor neuron?
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Cilia
Olfactory knob Olfactory rod Axon |
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Describe the olfactory axons
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Thin and unmyelinated - but ensheathed bu olfactory ensheathing cells
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Describe the pathway of the olfactory axons
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Travel through cribriform plate and terminate in olfactory bulb, converge on synaptic glomeruli mitral cells
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Which cells synapse on the same glomerulus?
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Receptor cells expressing the same receptor protein
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How many olfactory bulbs are there?
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2 - one in each nasal cavity
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What do the mitral cells merge to form?
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Lateral olfactory tract
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Where does this tract lead to?
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Piriform cortex
Lateral amygdala Anterior olfactory nucleus Olfactory tubercle Entohinal cortex |
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How might our perception of a smell change?
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Depending on if we are satiated or hungry
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What is anosmia?
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Reduced sense of smell or complete loss of smell
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How might damage to the temporal lobe affect the sense of smell?
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Might prevent an identification of the odour
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What is the "Proust effect"?
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Odour associated with an effect -> leads to memory
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Which fibres initiate sneezing and lacrimation?
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Trigeminal naked pain fibres
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Which organ is used to detect pheromones?
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Vomeronasal organ->accessory olfactory bulb->amygdala
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Which nerves are involved with taste?
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CN VII, IX and X
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Where might taste buds be found?
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Tongue, palate, epiglottis, oesophagus, larynx and pharynx
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What are the 4 types of cell found in taste buds?
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Type 1 and 2 - supporting cells
3 - gustatory 4 - basal cell |
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Describe the taste pathway
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Taste bud
Nucleus of solitary tract Thalamus/parabrachial nucleus Gustatory cortex/hypothalamus and amygdala |
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What are the 5 types of taste?
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Sweet, salty, sour, bitter, umami
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What else contributes to flavour?
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Texture, pain sensitivity, temperature
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How do molecules affect the taste cells?
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Bind to receptors on the microvilli -> release of excitatory neurotransmitters -> action potential
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What may taste stimuli do to the channels?
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Pass directly through ion channel
Bind to and block channel Bind to and open channel Bind to receptors that activate 2nd messenger systems that open/close ion channels |
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Cat difference?
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No sweet receptors
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Dog/cat/pig/rabbit/chicken
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water receptors that respond to clean water
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What are 3 taste modifiers?
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Topical anaesthetic
Gymnenic acid - sweet sensitivity suppressed Taste modifying protein - sour tastes sweet |
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What is ageusia?
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Absence of taste sense
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What is hypogeusia?
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Diminished taste sensitivity
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What is dygeusia?
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Disturbed taste sense
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