Digestion In Hydra-Definition and Process
written by Sidra BatoolThe animals of the genus Hydra belong to the class Hydrozoa and have a two-phase digestion process. In the extracellular phase, enzymes are released outside of the cells to break down the food. The intracellular phase takes place inside the cells, where the nutrients are absorbed.
Digestive System In Hydra
Hydra is an aquatic, diploblastic coelenterate. It has a vase-like body. Its body is composed of a Gastrovascular cavity or coelenterons.
The central cavity of the body functions as a digestive cavity. The animal has only one opening. It is called mouth. Such a digestive system having a single opening is called a sac-like digestive system. Its mouth is surrounded by mobile tentacles. The digestive cavity of this kind is called the gastrovascular cavity or coelenteron Nematocysts.
Hydra has numerous stinging cells or nematocysts. These nematocysts are embedded in the tentacles. Each nematocyst consists of a hollow thread. This thread is coiled within a Capsule. A tiny hair-like trigger projects outside.
Process Of Digestion
The following steps take place during the process of digestion;
Ingestion
The preys of hydra are animals like Daphnia or Cyclops.
The prey comes in contact with the trigger. The thread of the nematocyst comes out. It ejects poison and the prey is paralyzed or sometimes killed.
Hydra then grasps its prey with its tentacles These tentacles then push the prey into the digestive cavity through the mouth.
Digestion
Both extra and intercellular digestions take place in hydra;
Extracellular Digestion in Hydra
The glandular cells in the gastrodermis secrete enzymes. These enzymes start extracellular digestion. The flagellated gastrodermis cells and contraction of the body help in the mixing of food with enzymes. The enzymes break up the food into fine particles.
Intracellular Digestion in Hydra
The fine particles are then engulfed by phagocytic gastrodermal cells. These cells form digestive vacuoles. The process of digestion is completed in these digestive vacuoles.
Absorption
The digested food is then absorbed from the digested vacuoles.
Egestion
The indigestible food is expelled from the gastrovascular cavity through the mouth.
Related FAQs
How does digestion occur in Hydra?
Digestion in Hydra happens in two steps that are the extracellular phase and the intracellular phase. The first part of the digestion occurs outside of the cells of the endodermis and is considered an extracellular process. The second stage takes place inside the cells and is categorized as an intracellular process.
Does Hydra have extracellular digestion?
Hydra is an aquatic, diploblastic coelenterate that has both intracellular and extracellular modes of digestion.
What is the process of digestion in Hydra?
Digestion in hydra involves the following steps;
Ingestion
Digestion
Absorption
Egestion
How does hydra excrete waste?
Hydra does not have any excretory organ, thus the indigestible food is excreted from the gastrovascular cavity through the mouth.
Which type of digestive system does Hydra have?
Hydra has an incomplete digestive system, which means it has only one opening.
what type of cells function in intracellular digestion in hydra?
Intracellular digestion in Hydra is carried out by gastrodermal cells .
where does digestion take place in the hydra?
Digestion in Hydra occurs in the gastrovascular cavity, which is a single cavity that functions for both digestion and circulation.
Why is digestion in an earthworm more specialized than in hydra?
The digestion in an earthworm is more specialized than in Hydra because the earthworm has a more complex body plan and a more diverse diet.
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