Which body structure of a mollusk contains the internal organs?

Which body structure of a mollusk contains the internal organs?

visceral mass
The mollusk body can generally be divided into three regions: the head, the foot, and a cluster of internal organs called the visceral mass. The visceral mass includes many of the organs mentioned in the previous concepts such as the stomach, the heart, the nephridia, and the gonads.

Which part of the mollusk body is the tissue covering the body and secretes the shell?

In shelled molluscs, the mantle is the organ that forms the shell, and adds to the shell to increase its size and strength as the animal grows. Shell material is secreted by the ectodermic (epithelial) cells of the mantle tissue.

Are mollusk bodies segmented?

Mollusks may be primitively segmented, but all but the monoplacophorans characteristically lack segmentation and have bodies that are to some degree spirally twisted (e.g. torsion). The Pelecypoda are the bivalve mollusks and include oysters, clams, and scallops.

What are the three body parts of a mollusk?

Despite their diversity, mollusks share in common a three-part body plan that includes a head, a foot and a visceral mass.

What are the three main parts of a mollusks body?

All mollusks have a visceral mass, a mantle, and a foot. The visceral mass contains the digestive, excretory, and reproductive organs.

What are the three main structures that all mollusk species have in common?

The three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula (except for bivalves), and the structure of the nervous system.

What structure secretes the shell in mollusk?

The mantle (also known as the pallium) is the dorsal epidermis in mollusks; shelled mollusks are specialized to secrete a chitinous and hard calcareous shell.

What is the body wall of a mollusk?

All mollusks possess a flexible body wall, which surrounds a body cavity containing the internal organs. The wall, which varies greatly in shape in different species, is usually folded to form a structure called the mantle, which is attached at the top of the body and surrounds it like a tent; the shell is formed on the outside of the mantle.

Where is muscle tissue found in molluscs?

Muscle tissue is found in the body wall, and is particularly plentiful in the foot, which is used for locomotion in most mollusks (although some swim and some are sedentary), and in the mantle in species with reduced shells. The shell is formed by secretions of glandular cells in the mantle.

What is the function of epidermis in mollusks?

The epidermis usually contains gland cells that secrete mucus, which in mollusks has a variety of important uses, such as locomotion, food entrapment, and prevention of water loss.

What is the function of the radula in a Mollusca?

The digestive tract of the Mollusca is complex. The foregut region consists of an esophagus and a mouth cavity, which contains a toothed belt called the radula, found in almost all mollusks and peculiar to the phylum. The radula is usually used for scraping food, such as algae, from surfaces.