15: Olfactory and taste organ Flashcards
Define macrosmatic
Highly developed sense of smell/reliance on olfactory system
Define microsmatic
Weakly developed sense of smell/ less reliance on olfactory system
How long is a dog’s epithelium compared to humans?
dog: 10sq inches, humans: 1 sq inch
How many olfactory receptor genes do humans have?
300-400 different types
Tell me about the primary sensory receptor cells + cilia (how many)
50 million primary sensory receptor cells w 8-20 cilia down in a layer of mucus of about 60 microns thick
The location of olfactory receptors + why
In the roof of nasal cavity + prevention from flooding
Why is the olfactory receptor close to the brain?
Fast sensing for toxic gases
After how many days are olfactory receptors regenerated?
30-60 days
What do the Bowman’s glands produce?
mucus
T/F: The number of receptors do not determine olf sensitivity
False
What is our binding capacity?
300-400 diff types of OR gene, about 50 million receptor cells
T/F: Olfactory pathway is the direct connection to the brain
true
8 steps of physiology of olfaction
- Molecules dissolved in mucus
- Combination w/ receptors on cilia
- G-protein stimulation
- Adenyl Cyclase activated
- Increase IC cAMP
- Opening of Na+ channels
- Na+ influx
- Depolarization
What is Anosmia?
Absence of the sense of smell
What is Dysosmia?
Disturbed sense of smell
What is Hyposomia?
Reduced sense of smell (Vit. A deficiency and hypogonadism)
What is Hyperosmia?
Increased sense of smell (Adrenal insufficiency)
What is Ageusia?
Absence of sense of taste
What is Dysgeusia?
Disturbed sense of taste?
What is Hypogeusia?
Diminished sense of taste
What is Hypergeusia?
Increased sense of taste
Are taste and smell closely linked ?
Yes, but involve different receptors and receptive processes –> suggests an overlap in central processing
How long after do taste bud cells regenerate?
10 days
Location and structure of taste sensors
Location: top of tongue for access to food molecules
Designed to increase sensitivity
(SA)
How many taste buds are found on tongue
+ soft palate + pharynx?
~10 000 taste buds
How many receptor cells do taste buds consist of?
~50 receptor cells (type 3) surrounded by supporting cells
Basal cells (type 1&2) develop into supporting cells or Gustatory receptor cells
Physiology of taste
dissolution in saliva –> attachment to receptors –> generator potential –> action potential
What is the taste perception influenced by?
Odor, temperature and texture, psychological experiences w past experiences w food influence taste
The receptors of sweetness
T1R genes (3 types, sweetness) - T2R genes (28 types, bitterness)
