Oral Biology Exam-2 (Quiz MCQ)

Fungiform papillae are small mushroom-shaped structures on the tongue that carry taste buds. These taste buds contain specialized cells that are responsible for detecting different tastes such as sweet, sour, bitter, and salty. The other statements in the question are incorrect or unrelated to fungiform papillae.

Circumvallate papillae are responsible for bitter taste sensation. These papillae are located at the back of the tongue in a V-shaped row. They contain taste buds that are specifically tuned to detect bitter flavors. The other types of papillae mentioned, such as filliform, fungiform, and foliate, are responsible for other taste sensations such as texture, sweet, and sour, respectively. However, it is the circumvallate papillae that are primarily responsible for detecting bitter tastes.

The secretions of salivary glands are exocrine and merocrine. Exocrine glands release their secretions through ducts, which is the case for salivary glands as they release saliva into the oral cavity. Merocrine secretion is a mode of exocrine secretion where the secretory cells release their contents by exocytosis, without any loss of cellular material. This is the most common mode of secretion in salivary glands, where the secretory cells release saliva without any loss of cellular components.

Taste buds are composed of several types of cells, including supporting cells, receptor cells, and nerve fibers. The supporting cells do not carry taste hairs; instead, they provide structural support and help maintain the shape of the taste bud. The taste hairs, also known as gustatory hairs, are present on the receptor cells and are responsible for detecting taste stimuli. Therefore, the statement "The supporting cells of a taste bud carry taste hairs" is not true.

The cytoplasmic basophilia observed in acinar cells of the adult parotid gland is due to mucigen granules. Mucigen granules are large, round, and basophilic granules found in the cytoplasm of acinar cells. They contain glycoproteins, which are the main component of saliva secreted by the parotid gland. The basophilia is caused by the presence of these mucigen granules, which stain with basic dyes.

The vestibular fornix is a region that has a non-keratinized epithelium, meaning that the cells in this area are not hardened with keratin. This region is also loosely attached to the underlying structure, allowing for more flexibility and movement. The buccal mucosa, attached gingiva, and hard palate, on the other hand, have a keratinized epithelium and are more firmly attached to the underlying structures.

The correct answer is "Its growth is by pneumotization." The maxillary sinus is a paranasal sinus that develops as an outpouching of the nasal cavity. It grows by the process of pneumotization, which means that it expands and enlarges as air fills the sinus cavity. This growth helps to lighten the weight of the skull and also plays a role in the resonance of the voice. The other options are incorrect: the maxillary sinus begins to develop before 6 months of age, it is lined by ciliated columnar epithelium (not pseudostratified squamous epithelium), and its opening is in the nasal cavity (not the oral cavity).

The correct answer is "Parotid and submandibular." The parotid and submandibular glands are both types of major salivary glands in the human body. The parotid glands are located in front of the ears, while the submandibular glands are situated under the jawline. Both glands produce and secrete saliva into the mouth, contributing to the process of digestion.

The question asks about the glands that empty the circumvalate trough, and the correct answer is "Glands of Nuhn." The circumvalate trough refers to the groove surrounding the circumvallate papillae on the tongue. The Glands of Nuhn are located in this area and are responsible for secreting mucus to lubricate the tongue. Therefore, they are the glands that empty into the circumvalate trough.

Well developed mucous cells are responsible for controlling the concentration of sodium and chloride in saliva. These cells produce and secrete mucin, a glycoprotein that helps to lubricate and protect the oral cavity. The mucin secreted by these cells also helps to maintain the proper balance of electrolytes, including sodium and chloride, in saliva. Therefore, the presence of well developed mucous cells ensures the regulation of sodium and chloride concentration in saliva.