Question

Amoebocytes are found in sponges inside
(a) Pinacoderm
(b) Gastroderm
(c) Mesoglea
(d) All the above

Answer 1

Hint: Porifera is generally called sponges. It is the gelatinous matrix within a sponge, which fills the space between the external pinacoderm and the internal choanoderm.

Complete step by step answer:
A. Pinacoderm is the outer layer of the body wall of the sponges consisting of flattened pinacocytes.
B. Gastrodermis or gastral epidermis is the inner layer of the body wall of sponges consisting of specialized flagellated cells called choanocytes or collar cells.
C. Mesoglea also referred to as mesenchyme, is the interconnecting proteinaceous gelatinous matrix. Amoebocytes of varied types are found moving in between thin layers like archaeocytes, myocytes, chromocytes, thesocytes, etc.
- Sponges regulate their different physiological processes through a variety of mechanisms although they are simple organisms. These mechanisms regulate metabolism, locomotion, and reproduction.
- Sclerocytes are specialized amoebocytes which secrete biosilica (silica dioxide), which is a calcium- binding substance. Spicule is given strength and rigidity by biosilica and calcium.
- Like some of the vertebrates' white blood cells, amoebocytes are present in blood or body fluid in many animals and play a role in the organism's defense against pathogens. An amoebocyte can also digest and distribute food, dispose of waste, form skeletal fibers, combat infections, and turn into other cell types, depending on the species.
So, the correct answer is, ‘Mesoglea.’

Note: Sponges are the very simplest multicellular organisms, classified by their primitive cellular- level of organization, their porous bodies, and their filter-feeding system. Sponges have specialized cells that will perform distinct functions within the organism.