Question

Hastate plate is present in which part of the alimentary canal?
(a) Cardiac Stomach
(b) Pyloric Stomach
(c) Fundic Stomach
(d) Intestine

Answer 1

Hint: Hastate plate is necessary for food digestion and storage. It helps in filtering food and helps the food to move towards cardiac pyloric aperture.

Complete answer:
Hastate plate is present in the Cardiac Stomach part of the alimentary canal. Hastate plate in the cardiac stomach part of Crustacea, helps in filtering of food. It makes the mid-ventral floor of the cardiac stomach.

Additional Information:
Hastate plate looks like the head of a spear. Its side has thick growth of delicate setae and features a median ridge with gradually sloping sides. The posterior triangular part of the hastate plate is depressed and fringed with setae along its edge. A narrow lateral groove makes the lateral borders of a hastate plate and is supported by grooved plates.
Inner side of each lateral groove is guarded by the supporting lateral longitudinal folds of the hastate plate at the sides of cardiac pyloric aperture acts as a guiding ridges rod, bearing a row of delicate bristles. The outer side is bounded by a rigid plate. These bristles always keep moving in a living prawn. The posterior part of the hastate plate forms cardiac pyloric aperture. It guides the food towards the cardiac-pyloric aperture. Further cardiac pyloric aperture is guarded by four valves, a hastate plate makes anterior valve, and a semilunar fold of stomach wall makes posterior valve. While guiding ridges of hastate plate form lateral valves.

So, the correct answer is 'Cardiac Stomach'.

Notes:
1. The stomach is divided into three parts, Fundus, cardiac and pyloric region.
2. Hastate plates are found in prawns which belong to the phylum Arthopoda.
3. The plate shows variations in different species like the middle ridge is broad and high in
P. malcolmsonii and is dome shaped in P. lamarrei.