Flashcards in 1.30 Chemical Senses Deck (20)
What type of senses are smell and taste classified as?
Special Visceral Senses
What genetic components are there to why people may like or dislike some foods?
Some people have genes which allows them to taste certain flavours more intensely - e.g. dominant gene for the bitter taste in Brussel sprouts
Where can taste buds be found?
Oral cavity, pharynx and upper part of oesophagus
Which cranial nerves are responsible for taste?
VII - chordae tympani - ant. 2/3 of tongue
IX - lingual branch - post. 1/3 of tongue
X - superior laryngeal branch - epiglottis
What is the taste map myth?
All areas of the tongue can taste all flavours, however some areas are more sensitive to certain flavours - back bitter, from sweet
How many taste buds and taste cells are there on the tongue?
4000 taste buds - 30-100 taste cells
What is the function of basal cells?
Semi-differentiated - can divide to replace taste cells
Which substances (tastes) have the highest and lowest threshold?
High threshold - HCL - harmful
Low threshold - Glucose - needed
What is the bitter, sweet and umami (amino acid) taste transduction method?
G protein activated - second messenger - calcium enters and calcium acts upon vesicle (CICR) - exocytosis
What is the salt transduction method?
Na enters cell - causes depolarisation - na and ca enter cell - exocytosis
What is the acids (sour) taste transduction method?
H ions enter cell - causes depolarisation - na and ca enter cell - exocytosis
What is the gustatory pathway?
VII, IX, X - brainstem - nucleus of solitary tract - thalamus - ventroposterior - relayed gustatory cortex
What are the cell types of the found in the olfactory epithelium?
Receptor neurone - bipolar
Bowman's gland secretory cells
Olfactory ensheathing cells
What is the function of vomeronasal organ in animals?
Can detect pheromones - attraction to opposite sex
What is the function of sustentacular cell?
Supporting cell for neurones and shifts mucous
What is the smell transduction method?
1. odorant binds to receptor
2. activates Golf
3. alpha subunit activated in adenylyl cyclase
4. generates cAMP from ATP
5. depolarisation and ca release
6. ca opens chloride channels
What is the function of mitral and tufted cells?
Miteal and tufted cells - send info to olfactory tract
What is the function of granular cells?
Feedback comes through these cells, these modulate and alter other cells - act upon tufted and mitral cells - desensitisation
What is the function of the periglomerular cells?
Glomeruli act upon them as well as feedback - allows cells to modulate other cells - also acts upon glomeruli