What are the respiratory organs of mussel?

Mussels are called clam shells in some places. They live at the bottom of freshwater lakes, marshes, rivers, and so on. They are half buried in the sediment. The water pipes in and out of the back of the body are exposed, and water can flow into and out of the outer cavity. In order to complete the functions of feeding, breathing and excretion of feces and metabolites, filter tiny organisms and organic matter particles in the water, let's take a look at what the respiratory organs of mussels are.

Respiratory organs of mussel

The respiratory organ of mussel is Gill. The mussel has two lamellar gills on both sides of the clam body in the mantle cavity, and the outer Gill is shorter than the inner Gill. Each flap Gill is composed of internal and external bibranchial lobes, and its anterior and posterior margin and ventral margin synthesize a "U" shape, and the dorsal edge is the suprabranchial cavity. The Gill leaflet is composed of many longitudinally arranged Gill filaments with cilia on the surface, and each Gill filament is connected by a horizontally arranged filament septum. The small hole between the Gill filament and the filament septum is called Gill. There is a valvular septum between the two Gill lobules, which divides the Gill cavity into many tubules called the Gill canal. There are blood vessels in the silk septum and valvular septum, and there are also blood vessels and several supporting sticks in the Gill filament. Due to the wobble of the cilia on the Gill and mantle, the water enters the mantle cavity from the water entrance hole, passes through the Gill water hole to the Gill canal, ascends along the water tube to the suprabranchial cavity, flows backward, and is discharged through the outlet pipe. When water passes through the Gill, gas exchange is carried out, and the mantle also has the function of assisting breathing.

What kind of food does clam eat?

The main food of mussel is unicellular algae, protozoa and organic detritus, such as rotifer, flagellate, green eye worm, green alga, Scenedesmus, navicular algae, dinoflagellate, tetragonal algae, spindle diatom, rod star algae, crustacean residue and plant leaves. Diatoms are the main ones that are easily digested. Clam can not actively chase food, rely on the opening and closing of the clam shell, the swinging of the inner mantle cilia and Gill cilia cause the current, and the food enters the clam body with the water. The food enters the mantle cavity with the water, the particles move upward along the Gill filament to the base of the Gill, and then move forward to the lip flap. After the lip flap selection, the small particles enter the mouth, while the large particles move backward from the edge of the inner Gill. At the intersection of the two gills, they enter the mantle scar to the back end, and the two shells are suddenly closed out of the body. According to some statistics, the water flowing into the mussel body can reach 40 liters every day.

The digestive system of mussel

The mussel mouth is closed under the muscle in front of the position, which is a transverse seam. Each side of the mouth has a pair of triangular lips, large, dense cilia, sensory and feeding function. Behind the mouth is a short and wide esophagus, connected with a dilated stomach, and there is a pair of livers around the stomach, which can secrete amylase and sucrase and have ducts into the stomach. The posterior part of the stomach is the intestine, which is bent in the visceral mass, and then enters the heart, the rectum passes through the ventricle, and the anus opens on the posterior adductor muscle, near the outlet canal. There is a crystal rod between the stomach and intestines, which is a slender rod, the front end is thicker, and the top shape varies greatly, showing fine tip, dilatation, hook shape, disc curvature and so on. The crystal rod is located in the intestine, and its front end protrudes in the stomach and connects with the lower part of the gastric shield. The crystal rod may be stored food. under the condition of lack of food, the crystal rod disappears after 24 hours, re-feeding, and resumes after a few days.