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The Porifera phylum contains all sponges which are characterized by the small pores on the outer layer, which take in water. The cells in the sponge walls filter food from the water. Whatever is not uptaken by the sponge is pumped through the body out of a large opening. The class demosponges are
Intracellular digestion is divided into heterophagic digestion and autophagic digestion. [3] These two types take place in the lysosome and they both have very specific functions. [3] Heterophagic intracellular digestion has an important job which is to break down all molecules that are brought into a cell by endocytosis. [3]
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus.The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines.
In the small intestine, the larger part of digestion takes place and this is helped by the secretions of bile, pancreatic juice and intestinal juice. The intestinal walls are lined with villi, and their epithelial cells are covered with numerous microvilli to improve the absorption of nutrients by increasing the surface area of the intestine ...
The first stage, the cephalic phase of digestion, begins with secretions from gastric glands in response to the sight and smell of food. This stage includes the mechanical breakdown of food by chewing, and the chemical breakdown by digestive enzymes, that takes place in the mouth.
Gastrin is a hormone produced by enteroendocrine G cells in the pyloric glands. [1] All three of these stimulate parietal cells to secrete hydrochloric acid and intrinsic factor. The chief cells secrete pepsinogen in response to gastrin and especially Ach, and ACh also stimulates mucus secretion. [1]
The female lays her eggs on vegetation overhanging water. The larvae hatch and drop into the water where they seek out sponges to feed on. They use their elongated mouthparts to pierce the sponge and suck the fluids within. The larvae of some species cling to the surface of the sponge while others take refuge in the sponge's internal cavities.
It takes place either in the lumen of the digestive system, in a gastric cavity or other digestive organ, or completely outside the body. During extracellular digestion, food is broken down outside the cell either mechanically or with acid by special molecules called enzymes. Then the newly broken down nutrients can be absorbed by the cells nearby.