Taste and Olfaction Flashcards
Olfactory Receptor Cells
Sensory Neurons
(4-8 week lifespan)
Basal Cells
Stem cells that can regenerate sensory cells
Bowmans gland
Produce mucus layer surrounding cilia
- Odor detecting GPCRs are located in the cilia
Supporting Cells
Provide structure and release chemicals to block toxins
Glomerulus Input and Output
- Olfactory sensory receptor cells excite glomeruli cells
- Mitral and tufted cells send output from glomeruli to cortex
- Granule and periglomerular cells produce GABA inhibition
Olfactory ensheathing cells aid axon guidance in olfactory neurons
olfactory ensheathing cells have been used experimentally to repair severed axons in the spinal cord.
2 Glomeruli for 1 Odorant receptor type (gpcr)
Glomerulus codes for a specific GPCR
CNG channel lets :
Na and Ca into the cell
- Ca opens a Cl channel, (Cl out)
CNG channel and chloride channel produce a depolarization in the olfactory cell.
Conscious Odor detection
Primary olfactory cortex
Limbic System
(hippocampus and amygdala)
- Olfactory signals go to the limbic system, involved in memory and emotion.
Anosmia
Loss of smell
Parosmia
Distorted Sense of Smell
Ex. Flowers smell like feces
Chorda tympani (branch of facial Nerve CNVII)
ant. two thirds of the tongue
Glossopharyngeal nerve (CNIX)
Posterior third of the tongue
Vagus Nerve (CN X)
few taste buds in the larynx and upper esophagus
Taste Bud
- Found in the tongue, palate, esophagus, and epiglottis
- 1 week lifespan
Taste Receptor Subtypes
Sour, Salt, Sweet, Bitter, Umami
- Sour and Salt are channels
Others are GPCRs
Bitter Taste Receptors
Found in gut and lung, mediating responses to toxins and bacteria.
Gustatory Central Pathways
Solitary nucleus in the medulla -> Thalamus ->Gustatory Cortex
