Question

A spectacular marine animal has a network of glassy spicules that forms a sac-like structure. This animal does not have true tissues. It is a suspension feeder. What cells or structures does this sac-shaped animal use to get nutrients from its feeding cells to other parts of its body?

Answer 1

Answer:

Sponges use choanocytes or flagellated channels to get nutrients from the feeding cells to other parts of their body.

Explanation:

Sponges are marine animals with a sac-shaped body. The epidermis is composed of polygonal flat cells called pinacocytes and pores protected by porocytes. Under the epidermis, there is a protein matrix called mesenchyme, which is composed of spicules and amibocytes. By the interior side of the sponge, there are the choanocytes. These are ovoid cells that can be shaping the spongocoele (internal cavity of the sponge), with an extreme attached to the mesenchyme and the other extreme projected to the spongocoele, or can be grouped in spaces called flagellated channels.

These animals depend on water to get oxygen and food to the inside of the sac and take excrements and reproductive cells to the outside. Sponges feed on small detritus particles and suspending organisms that get near the animal by water streams produced by choanocytes.

Particle size is essential. Only the small ones can get through the flagellated channels, where they get stuck to the choanocytes and are encapsulated by the cells. If the choanocytes are too small, the particle is transferred to the amibocytes for digestion. These last ones also act as food storages. Excrement products are dragged by a water stream.