Question

In cockroach the common duct of salivary reservoir open at base of the
(a) Pharynx
(b) Maxilla
(c) Mandible
(d) Hypopharynx

Answer 1

Hint: There are two salivary glands present in the cockroach. These salivary glands release their secretion with the help of a common duct, which opens at the base of the buccal cavity. It is also known as lingua or tongue.

Complete answer:
The common duct of the salivary reservoir opens at the base of the hypopharynx. It is a tongue-like structure hanging between the mouthparts. It performs the function of mixing the food in saliva.
Between the mouthparts of the cockroach, there is a small space called the pre-oral cavity, which lies in front of the mouth. Hypopharynx hags in this cavity.
Other mouthparts of cockroach:
1. Labrum:It is also called an upper lip, is a broad, movable, rectangular plate. Its inner surface has a gustatory(taste) lining called the epipharynx. It serves to hold the food.
2. Mandibles:These are one pair of highly rough triangular structures present on each lateral side of the head. The lower part of the inner margin is called the molar area and has teeth like denticles, while its soft upper edge is called prostheca. These help in grinding the food.
3. First maxillae These lie below the mandible. Each maxillae divides into two branches. The first maxillae are formed of the cardo, stipes, lacinia, galea, and 5-segmented maxillary palp with sensory bristles. The first maxillae act as accessory jaws. They also serve to clean the antennae and the foreleg.
4. Labium or second maxillae:Labium is a broad plate and forms the posterior margin of the pre-oral cavity, so is called the lower lip. It is formed of mentum, submentum, prementum, glossae, paraglossal, and two three-segmented labial palps with sensory bristles. Labium prevents the falling of food particles and pushes the food in the mouth.

So, the correct answer is, ‘Hypopharynx.’

Note: The mouth of the cockroach is a slit-like aperture and lies at the top of the preoral cavity. It is surrounded by the biting and chewing types of mouthparts. It is for ingestion. The mouth lies in the foregut or stomodaeum part of the alimentary canal.