Question

Salivary glands of cockroach open on
(a)Maxilla
(b)Hypopharynx
(c)Labium
(d)Labrum

Answer 1

Hint: Salivary glands in cockroaches are known to open on a structure that acts as a tongue in cockroach and lies within the cavity enclosed by the mouthparts. The salivary glands discharge saliva through these structures.

Complete answer:
The salivary glands of cockroach open on the Hypopharynx. It is a tongue-like structure and through which the salivary glands secrete saliva. Salivary glands are paired and white structures and are situated one on either side of the crop in the prothoracic region. It consists of several lobes of secretory acini. They are composed of a glandular part and a hollow receptacle or reservoir. The receptacle is situated between paired glands of each side and remains connected through a duct. The ducts of each gland unite to a single efferent salivary duct that then fuses with the opposite duct to form the main salivary duct. Two reservoirs are associated with the secretory tissue. The reservoirs open into reservoir ducts that accompany the efferent salivary ducts. These glands are compressed, made up of hexagonal glandular cells and each of them opens into a small narrow duct.

Additional Information: -There are five different structures which are used for the initial collection and processing of food; Labrum, Maxillae, Labium, Mandibles, Hypopharynx.
-Labrum is a cover that may be loosely referred to as the upper lip and Mandibles refers to hard, powerful cutting jaws.
-Maxillae are less powerful than the mandibles. They are used to steady and manipulate the food. They have a five segmented palp which is sensory and often concerned with taste.
-Labium is the lower cover, often referred to as the lower lip. It actually represents the fused pair of ancestral second maxillae.
Hypopharynx is a tongue-like structure on the floor of the mouth.
Therefore, the correct answer is option B.

Note: The salivary glands in cockroaches are of the acinar type and can produce two different qualities of saliva.
- The control of salivation is achieved mainly via serotonergic and dopaminergic neurons.
-The paired salivary glands consist of different cell types with different functions; C-cells and P-cells. C-cells secrete proteins, whereas P-cells secrete ions.