Tag: organ of taste

Questions Related to organ of taste

Which of the following states the location of taste buds on the tongue?

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Pouches

  2. Papillae

  3. Palate

  4. Pupillae

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Correct Option: B
Explanation:

  • Lingual papillae (singular papilla) are the small, nipple-like structures on the upper surface of the tongue that give it its characteristic rough texture.
  •  The four types of papillae on the human tongue have different structures and are accordingly classified as circumvallate (or vallate), fungiform, filiform, and foliate. All except the filiform papillae are associated with taste buds. Hence, Papillae states the location of taste buds on the tongue.
 So, the correct answer is 'Papillae'.

Bitter taste of food can be transduced by

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. The blockage of efflux of K+

  2. The blockage of influx of K+

  3. The blockage of efflux of Na+

  4. The blockage of efflux of Cl-

Show answer
Correct Option: A
Explanation:

Bitterness is the most sensitive of the tastes and perceived as unpleasant, sharp, or disagreeable. The transduction of bitter tastes involves several mechanisms: 

1) Blockage of the efflux of K+ by a number of hydrophilic bitter substances generates a depolarizing potential.
2) Interaction with a receptor membrane receptor coupled to the G protein, gustducin, and activation of a cAMP-dependent protein kinase with blockage of K+ channels and

3) Involves a receptor protein linked to G-protein and activation of phospholipase C, which results in substrate hydrolysis to IP3, releasing Ca2+ from intracellular stores.
So, the correct answer is option A.

The taste sensitivity is dependent upon

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Concentration of taste

  2. Concentration of food

  3. Solubility of taste in saliva

  4. Both A and C

Show answer
Correct Option: D
Explanation:
Taste sensitivity refers to the intensity with which one perceives different tastes and flavours. It is dependent upon the concentration of the taste molecules as well as their solubility in saliva. It does not depend upon the concentration of food.
So, the correct answer is option D.

The taste of salt is mediated by

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Na+

  2. Ca+

  3. K+

  4. None of the above

Show answer
Correct Option: A
Explanation:
The taste of salts is mediated by Na$^+$ ions which do not interact with a membrane receptor but diffuse through a Na$^+$ channel located in the microvilli and apical membrane. Anions such as Cl$^-$ contribute to the salty taste, but anions are transported into these cells by a paracellular route. The influx of these ions of salt evokes a depolarization in the apical membrane.
So, the correct answer is option A.

Fungiform papillae carry which of the following cranial nerve?

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. VII

  2. IX

  3. X

  4. None of the above

Show answer
Correct Option: A
Explanation:
  • Fungiform papillae contain taste buds (especially for bitter taste), temperature receptors and have a good blood supply. They are scattered over the top and sides of the tongue, mainly towards the tip.
  • Cranial nerves are the nerves which arise from the brain and spinal cord. The facial nerve is the 7th cranial nerve it arises from the pons of the brain stem.
  • The fungiform papillae are innervated by the VII cranial nerve. Hence through 7th cranial nerve fungiform papillae send sensory signals of taste to the brain stem.
  • So, the correct answer is 'VII'.

The cranial nerve that carries information of taste from epiglottis is

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. VII

  2. IX

  3. X

  4. VIII

Show answer
Correct Option: C
Explanation:

The taste receptor cells send information detected by clusters of various receptors and ion channels to the gustatory areas of the brain via the seventh, ninth and tenth cranial nerves. The X nerve or vagus nerve carries information from the back of the oral cavity and the epiglottis.

So, the correct answer is option C.

The food tastes sour when
biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Hydrogen ion pass through the same channel as that of the sodium ion

  2. Hydrogen ion blocks the potassium channel

  3. Hydrogen ion blocks the calcium channel

  4. Both A and B

Show answer
Correct Option: D
Explanation:
The sour taste originally comes from acidic foods, in which their molecules dissociate into proton/positive hydrogen ions. Common chemical molecules that dissociate into hydrogen ions to characterize a sour or tangy taste are carboxylic acids which have a distinctive carboxyl functional group, -COOH. The hydrogen proton of acids and sour foods can influx through the Na$^+$ channels, or through a proton transport membrane protein. Some acids block the efflux of K$^+$ at the microvilli. The resulting influx of protons or a reduction in K$^+$ conductance will initiate receptor potentials in response to the quality of sour tastes.
So, the correct answer is option D.

Which of the following taste was identified by Kikunae Ikeda?

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Sour

  2. Umami

  3. Sweet

  4. Salt

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Correct Option: B
Explanation:
The umami taste was identified by Japanese chemist kikunae Ikeda. The taste signals the presence of the amino acid L- glutamate which triggers a pleasurable response and thus encourages the intake of peptides and proteins.
So, the correct answer is option B.

Which of the following taste is mediated by inotropic glutamate receptor?

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. Sweet

  2. Bitter

  3. Umami

  4. None of the above

Show answer
Correct Option: C
Explanation:
  • Ionotropic glutamate receptors are ligand-gated ion channels that are activated by the neurotransmitter glutamate.
  • Umami describes foods with an inherent savoriness(delicious, tasty). It has been described as brothy or meaty. You can taste umami in foods like Parmesan cheese, seaweed, miso, and mushrooms, which contain a high level of the amino acid, glutamate.
  • As the umami food contains a high level of amino acid glutamate its mediated by ionotropic glutamate receptor. The receptor detects glutamate in the food and sends signals to the brain.
  • So, the correct answer is 'Umami'.

Taste receptors detect the taste by

biology windows of knowledge human tongue organ of taste tongue : the organ of taste

  1. G protein-coupled mechanism

  2. Contractile mechanism

  3. Feedback inhibition

  4. None of the above

Show answer
Correct Option: A
Explanation:
  • The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the cheek, and epiglottis.
  • Taste receptors detect the taste by G protein-coupled mechanism.
  • G protein-coupled receptors constitute a large protein family of receptors that detect molecules outside the cell and activate internal signal transduction pathways and, ultimately, cellular responses. Coupling with G proteins.
  • So, the correct answer is 'G protein-coupled receptor.