Category: Biology Second Paper

Streptolin Glutinant medium type nematocyst. Its capsule is small and the butt is not well formed. It lacks barbs, but has barbules. Its stems are long, spiny and open at the apex.
Action of Streptolin Glutinant
(i) It traps prey.
(ii) Helps in locomotion.
(iii) secretes sticky substances.

Stenotile is the largest of the four types of nematocysts of Hydra. Its capsule is filled with a poisonous liquid called hypnotoxin. Its butt is fat. The butt has three large spines. It’s called a barb. Butt has three rows of barbules.
Work of stenotil or penetrant
(i) It paralyzes prey with hypnotoxin.
(ii) Its trigger grips the prey.

Nematocysts are small sacs with patchy filaments located in nidocyte cells. Normally the sutraka is inserted into a sac or capsule with a butt and a fork. A nematocyst once shed never reenters. In 1965, scientist Werner identified 23 types of nematocysts in the bodies of Nideria animals. However, four types of nematocysts can be seen in Hydra. Dr. Siddiq Publications
1. Stenotile or penetrant: Stenotile is the largest of the four types of nematocysts of Hydra. Its capsule is filled with a poisonous liquid called hypnotoxin. Its butt is fat. The butt has three large spines. It’s called a barb. Butt has three rows of barbules.
Work of stenotil or penetrant
(i) It paralyzes prey with hypnotoxin.
(ii) Its trigger grips the prey.
2. Streptolin Glutinant or Holotrichus isorhiza: Streptolin Glutinant medium type nematocyst. Its capsule is small and the butt is not well formed. It lacks barbs, but has barbules. Its stems are long, spiny and open at the apex.
Action of Streptolin Glutinant
(i) It traps prey.
(ii) Helps in locomotion.
(iii) secretes sticky substances.
3. Steriolin glutinant or Atrichus isorhiza: Steriolin glutinant is the smallest nematocyst. Their butt is not well formed. Barbs and barbules are absent. Its stems are short, thornless and open at the apex. Dr. Siddiq Publications
Action of stearoline glutenin
(i) It helps in locomotion.
(ii) binds the hydra to an object.
(iii) secretes sticky substances.
(iv) Capture the victim.
4. Volvent or Desmonym: Volvent is a relatively small nematocyst. They do not have butts, barbs and barbules. Its stem is thick, short, elastic, spineless and closed at the apex. There is only one patch of Sutra inside its capsule. The sutraka remains patchy even when thrown. As soon as it is thrown, it creates many screws like a cork-screw.
Volvent’s work
(i) It grasps the prey.
(ii) It helps in locomotion.

1. Defense: Nematocysts contain a poisonous substance called hypnotoxin. Hydra defends itself with this toxic substance.
2. Prey capture: Hydra captures food by means of nematocysts. Then paralyze the victim. Dr. Siddiq Publications
3. Movement: Nematocyst cells help the hydra to move. Different types of movements occur in hydra. Dr. Siddiq Publications
4. Clogging the body: Nematocysts secrete sticky substances. By this, the hydra is stuck to an object. Dr. Siddiq Publications

The word Cnidoblast is derived from the Greek words knide meaning nettle and blastos meaning germ. The goblet or flax-shaped cells on the exterior of hydra are called nidoblast cells. It can be round, oval, pear-shaped, cup-shaped or oval-shaped. Nidoblast cells are found everywhere in the body except the soles of the feet. But its number is more in Karshika. Sometimes the cells are arranged in clusters. A group of them is called a battery.
1. Integument: Each nidoblast cell is covered by a bilayered envelope. Outer cover and inner cover. It is composed of proteins and lipids. Between the two envelopes are granular cytoplasm, a nucleus, mitochondria, lysosomes, ribosomes, etc.
2. Nematocyst: Small cysts with twisted secretions present in nidoblast cells are called nematocysts. The sac of nematocyst is called capsule. Capsules contain the poisonous liquid hypnotoxin. Hypnotoxin is composed of proteins and phenols. Hypnotoxin poison is neurotoxic in nature. That is, it acts on the victim’s nervous system. The level of this venom is 75% similar to that of a gokra or cobra snake. The nematocyst has a long and hollow filament at its tip. The broad part of the base of the sutraka is called the butt or shaft. The butt has three large spines called barbs. The butt consists of spirally arranged small barbule spines. Normally, the nematocyst is inserted into the sac with butts and spines. A nematocyst once shed never reenters.Dr. Siddiq Publications
3. Operculum: The mouth of nematocyst has a lid like part. It is called operculum. It moves sideways when exposed.
4. Nidocile: The free end of the nidocyte cell consists of a tough, firm, tiny and hypersensitive hollow spine. It is called nidosil. It is a transformed cilium. It works like a trigger. As a result, patched sutraka is thrown out. Dr. Siddiq Publications
5. Muscle fibers and lasso: Several muscle fibers emerge from the lower end of the nematocyst. Besides, there is a twisted thread called lasso at the lower end.

The word Cnidoblast is derived from the Greek words knide meaning nettle and blastos meaning germ. The goblet or flax-shaped cells on the exterior of hydra are called nidoblast cells. It can be round, oval, pear-shaped, cup-shaped or oval-shaped. Nidoblast cells are found everywhere in the body except the soles of the feet. But its number is more in Karshika. Sometimes the cells are arranged in clusters. A group of them is called a battery.
1. Integument: Each nidoblast cell is covered by a bilayered envelope. Outer cover and inner cover. It is composed of proteins and lipids. Between the two envelopes are granular cytoplasm, a nucleus, mitochondria, lysosomes, ribosomes, etc.
2. Nematocyst: Small cysts with twisted secretions present in nidoblast cells are called nematocysts. The sac of nematocyst is called capsule. Capsules contain the poisonous liquid hypnotoxin. Hypnotoxin is composed of proteins and phenols. Hypnotoxin poison is neurotoxic in nature. That is, it acts on the victim’s nervous system. The level of this venom is 75% similar to that of a gokra or cobra snake. The nematocyst has a long and hollow filament at its tip. The broad part of the base of the sutraka is called the butt or shaft. The butt has three large spines called barbs. The butt consists of spirally arranged small barbule spines. Normally, the nematocyst is inserted into the sac with butts and spines. A nematocyst once shed never reenters.Dr. Siddiq Publications
3. Operculum: The mouth of nematocyst has a lid like part. It is called operculum. It moves sideways when exposed.
4. Nidocile: The free end of the nidocyte cell consists of a tough, firm, tiny and hypersensitive hollow spine. It is called nidosil. It is a transformed cilium. It works like a trigger. As a result, patched sutraka is thrown out. Dr. Siddiq Publications
5. Muscle fibers and lasso: Several muscle fibers emerge from the lower end of the nematocyst. Besides, there is a twisted thread called lasso at the lower end.
Nidoblast function
1. Defense: Nematocysts contain a poisonous substance called hypnotoxin. Hydra defends itself with this toxic substance.
2. Prey capture: Hydra captures food by means of nematocysts. Then paralyze the victim. Dr. Siddiq Publications
3. Movement: Nematocyst cells help the hydra to move. Different types of movements occur in hydra. Dr. Siddiq Publications
4. Clogging the body: Nematocysts secrete sticky substances. By this, the hydra is stuck to an object. Dr. Siddiq Publications

The jelly-like sticky extracellular layer between the epidermis and gastrodermis of Nidaria is called mesoglia. It is thin, colorless and elastic. Its diameter is 0.1 micron. Dr. Siddiq Publications
Function of mesoglia
1. Mesoglia serve as the foundation of the epidermis and endoderm.
2. It acts as an attachment point.
3. It makes the body contract and expand.
4. Acts as a flexible skeleton of the body.
5. It contains myofibrils.

The innermost cell layer of the body wall is called the gastrodermis. The thickness of the gastrodermis is two-thirds that of the body wall. It contains 5 types of cells. Nutrient cells, glandular cells, interstitial cells, nerve cells and sensory cells.
1. Nutritive cells: Nutritive cells are located throughout most of the gastrodermis. It looks stunning. Each cell has a large nucleus and cavity. It forms contractile fibrous fascicles. Nutrient cells can be divided into two types. Flagellar cells and transient cells. Dr. Siddiq Publications
(i) Flagellar cells: These cells have 1-4 thread-like flagella at the free end.
(ii) Transient cells: The free end of this cell has transient cells.
Nutrients are cell functions
(i) It thins and thickens the body by contraction-expansion.
(ii) Flagella transform the food material into particles.
(iii) Acts like a sphincter to open and close the mouth.
(iv) It allows water to enter the mouth.
(v) Digests food.

During the reproductive season, spermatozoa and ovum are formed from interstitial cells in the hydra body stem. The testes are above and the ovaries are below. The testicles produce sperm and the ovaries produce eggs. Sperm are very small and nucleated. It consists of head, midsection and movable tail. Eggs are large, round and have three polar bodies.
Function of reproductive cells: Sperm and egg participate in reproductive function.

Gland cells are located in the peduncle, hypostome and peduncle. Cells may appear cylindrical, granular, or oval. It contains mucous glands, enzyme glands and glands that secrete mucus.
Function of glandular cells
(i) A cell helps in digestion of food.
(ii) The secreted sticky juice keeps the hydra attached to an object.
(iii) It helps in locomotion by creating momentum.
(iv) Helps hydra to float in water by creating bubbles.