Question

3. Outline the olfactory pathway. 4. Describe a taste bud. Include the locations where they are found. List all cell types present and give their functions.

Answer 1

3. ANS: Olfactory pathway involved in carrying sense of smell via the first cranial nerve known as olfactory nerve from the nose.

Olfactory pathway-

Olfactory receptor from roof of nasal cavity form olfactory epithelium. It have olfactory neuron with axons of olfactory nerve goes to olfactory bulb. From bulb to olfactory glomeruli which contain 4 cells type- mitral cells, tufted cells carry excitatory neuron while granule cell periglomerular cells carry inhibitory neuron.

Mitral cells projects to - anterior olfactory nucleus, olfactory tubercle, piriform cortex, amygdla, entrohinal cortex.

From primary olfactory cortex to dorsomedial Thalamic nucleus to amygdala for emotional response, and to entorhinal cortex for olfactory memory, in cortex their is conscious discrimination of odour.

4. ANS: Taste buds are the sensory organs that are found on your tongue and you to experience tastes that are sweet, salt, sour and bitter. Taste buds contain receptor cells for taste stimuli are located in structures. Some taste buds are also found on the soft palate, epiglottis and lower oral pharynx.

Types of taste buds:

Taste buds may have a conical, cylindrical or mushroom shape depending on its size and function.

1. The fungiform or mushroom-shaped papillae:

Mushroom-shaped papillae are found on the front of the tongue and they are the easiest to differentiate of the rest of the papillae. These papillae have a pinkish color, a voluminous head and are distributed over the entire surface of the tongue, mainly in front of the goblet papillae. This type of taste buds is usually used to taste candy .

2. The filiform papillae:

The filiform papillae are conical in shape, apart from being receptors of the salty and acid flavors, they exert a tactile function and thermal throughout the surface of the tongue.

3. The follicular papillae:

The foliate papillae are found in the lateral and small folds of the lingual mucosa, as well as on the dorsum of the tongue. They are the papillae that are less developed.

4. The circumvallate or goblet papillae:

The goblet is located on the back of the tongue, where the throat begins. The human being has between 7 and 12 large circumvallated papillae, responsible for perceiving the bitter taste. Each of these papillae has the shape of an inverted cone and they are placed in a depression similar to a chalice.