Special Senses Flashcards
(28 cards)
Where are taste receptors located?
Taste receptors are distributed over the surface of the tongue and other regions such as the mucosa of the pharynx, epiglottis, and proximal esophagus.
What are the three types of tongue papillae where taste buds are clustered?
- Circumvallate papillae
- Fungiform papillae
- Filiform papillae
What is the structure of taste buds composed of?
Taste buds are composed of about 40 modified epithelial cells (taste cells) which are of principally two types: * Gustatory receptor cells
* Supporting (sustentacular) cells
What is the function of gustatory receptor cells?
Gustatory receptor cells have cilia on one side and nerves on the other side, allowing them to transmit taste sensations.
What are taste pores?
Taste pores are minute openings on the tongue surface through which cilia from taste cells project into the mouth cavity.
Which cranial nerves innervate the taste buds?
- Chorda tympani (branch of facial nerve)
- Glossopharyngeal nerve
- Vagus nerve
What is the role of the chorda tympani nerve in taste sensation?
It carries sensation from the anterior 2/3 of the tongue to the geniculate body.
What are the four types of primary taste sensations?
- Sweet
- Sour
- Salty
- Bitter
What is the additional type of taste sensation recently recognized?
Umami
Where are taste buds highly sensitive to sweet located?
Taste buds highly sensitive to sweet are located at the tip of the tongue.
Where are taste buds highly sensitive to bitter located?
Taste buds highly sensitive to bitter are located at the back of the tongue.
Where are taste buds highly sensitive to sour and salty located?
Taste buds highly sensitive to sour and salty are located on the sides of the tongue.
What produces the sweet taste?
Sweet taste is produced mainly by organic substances such as sugars, alcohol, aldehydes, ketones, and saccharides.
What produces the sour taste?
Sour taste is produced by acids (including organic acids) that ionize to H+ and stimulate taste receptor cells.
What produces the salty taste?
Salty taste is produced by cations released from inorganic salts.
What is responsible for the bitter taste?
Bitter taste is offered by long-chain organic compounds that contain nitrogen (e.g., quinine sulfate, urea, caffeine) and alkaloids (e.g., nicotine, morphine).
True or False: The taste sensation pathway includes the gustatory area of the cortex and thalamus.
True
What is the olfactory organ?
The olfactory organ lies in the olfactory epithelium on either side of the nasal septum, just inferior to the cribriform plate of the ethmoid bone.
What is the structure of the olfactory neuroepithelium?
It is composed of three types of cells and one gland known as Bowman’s gland, which secretes mucus.
What are the types of cells in the olfactory neuroepithelium?
The cells are: (a) Supporting cells, (b) Receptor cells, and (c) Basal cells.
What are supporting cells?
Supporting cells are columnar epithelial cells with large oval nuclei that end in microvilli and secrete mucus.
What are receptor cells?
Receptor cells are bipolar neurons known as olfactory rods, which end in fine cilia that react with odoriferous molecules.
What are basal cells?
Basal cells are few in number and serve as parent cells for supporting cells.
What is the neural basis of olfaction?
Each receptor cell gives rise to one axon that joins with other axons to form fila olfactoria or the olfactory nerve.
