The habitat of flat worms. Types of flat worms of the habitat of flat worms

Number of species: About 25 thousand.

Habitat: Inhabit everywhere in wet environments, including fabrics and other animal organs.

Structure: Flat worms are the first multicellular animals, in which bilateral symmetry, three-layerness, real organs and tissues appeared during evolution.

Bilateral (bilateral) symmetry - this means that through the body of the animal you can spend an imaginary axis of symmetry, while the right side of the body will be mirrored to the left.

During the embryonic development of three-layer Animals are laid three layers of cells: outdoor - etoderma, middle - mesoderma, internal - entoderma. Each layer develops certain organs and fabrics:

skin (epithelium) and nervous system are generated from the ectoderm;

mesoderma - muscle and connective tissue, sexual, excretory system;

from Entoderma - digestive system.

In flat worms, the body is flattened in the spin-abdominal direction, the body cavity is absent, the space between the internal organs is filled with mesoderm cells (parenchyma).

Digestive system Includes mouth, throat and blind intestinal. Absorption of food and excretion of undue residues occurs through the mouth. In the ribbon worms, the digestive system is completely absent, the nutrients are absorbed by the entire surface of the body, being in the intestine of the owner.

Selective organs - protonefridia. They consist of thin branching tubules, at one end of which are located flame (flicker) cellsstar shape immersed in a parenchyma. Inside of these cells, a bug of cilia (flickering flame) is departed, the movement of which resembles the flicker of the flame (hence the name of the cell). Flame cells are captured from parenchyma liquid decay products, and the cilia drive them into the canal. The tubules open on the surface of the body separating sometimes, through which decomposition products are removed from the body.

Nervous system staircase ( orthogon). It is formed by a large head paired nervous knot (ganglia) and six nervous barrels from him: two on the abdominal side, two on the dorsal and two sides. Nervous trunks are interconnected by jumpers. The nerves to organs and the skin depart from Ganglia and trunks.

Reproduction and development:

Flat worms - hermaphrodites. Sex cells ripen in germ glanes (gonads). Hermaphrodis has both men's glands - the seeds and women's - ovaries. Fertilization - internal, usually cross, i.e. Worms exchange seed fluid.

Class Classified Cherry

Dairy plane, a small water animal, an adult individual has a length of ~ 25 mm and a width of ~ 6 mm, the body is flat, milk-white. At the front end of the body there are two eyes, distinguishing light from darkness, as well as a pair of tental (chemical feeling) necessary to search for food. Planaria move, on the one hand, thanks to the work of cilia covering their skin, on the other hand, thanks to the reduction of the muscles of the skin-muscular bag. The space between the muscles and the internal organs is filled with Parenkhima, in which they meet intermediate cellsresponsible for regeneration and useless reproduction.

Planaria - predators feed on small animals. The mouth is located on the abdominal side, closer to the middle of the body, there is a muscular throat from it, from which three branches of the closed intestine are departed. Capturing the sacrifice, the planaries sucks its contents. In the intestine, digestion under the action of enzymes (intestinal), intestinal cells are able to capture and digest pieces of food (intracellular digestion). Unpained food remnants are removed through the mouth.

Reproduction and development. Rishichny - hermaphrodites. Fertilization cross. Fertilized eggs fall into the cocoon, which worm postpones on underwater items. Development direct.

Class of chowers

4 - sporocyst; 5 - red; 6 - churches; 7 - Adolescarius.

Class of tape worms

Bull chain - Ribbon worm, reaches a length from 4 to 12 meters. The body includes a head with suction cups, neck and gate - sealer tape. The youngest segments are at the neck, the oldest are the bags filled with eggs, are at the rear end, where they come off one by one.

Reproduction and development. Bull Chain - Hermaphrodge: There is one ovary in every segment and many seeds. It is observed both cross fertilization and self-exploitation. The rear segments filled with ripe eggs are opened, and, with the feces, are outward. Cattle (intermediate owner) can swallow eggs along with grass, microscopic larvae with six hooks come from eggs, which through the intestine wall fall into the blood and spread throughout the body of the animal and are recorded in the muscles. Here, the six-sided larva grows and turns into finn - A bubble, inside of which is a chain chain head. A person can become infected with docks, aief is not sufficiently roasted or woven meat of an infected animal. In the stomach of a man from the fins, the head comes out, which is attached to the intestinal wall. From the neck, new segments are buded - the worm grows. The bullish chain allocates poisonous substances that cause intestinal disorders and anemia in humans.

Development pork chain It has a similar character, his intermediate owner besides a pig and boar, there may be a person, then in his muscles are developing. Development wide Lenteza accompanied by a change of two intermediate owners: the first - the wrapping (cyclops), the second is a fish, eating the lap. The final owner can be a person or a predator, eating infected fish.

New concepts and terms: Mesoderma, skin-muscular bag, tugement, hypoderma, reduction, protonphridey (fiery cells), orthogon, gates, gangliy, gonads, hermaphrodis, direct and indirect development, final and intermediate owner, Miracidium, churches, Finn, segment, armed and unarmed tapeworm.

Questions for consolidation.

1. Who are called an intermediate owner? Final?

6. What is dangerous to drink raw water, swim in water bodies near the grazing of livestock? Why after communicating with animals you need to wash your hands with soap?

7. For what worms oxygen is destroyed?

8. What aromorphoses led to the appearance of the type of flat worms?

Lectures on zoology

Type round worms

Answer:

· general characteristics Round worms

· The structure of the body of the Asskarid of Human

· Reproduction and development of human ascaris

· Classification of round worms, varieties of species

· The value of round worms in the nature and life of a person

Flat worms, which are included in the group of bilateral symmetric, studies science biology. Flat worms (PlatyHelminthes) are not the only representatives of this group, it belongs to more than 90% of animals, including ringed and round worms, arthropods, mollusks, etc.

Types of flat worms are diverse and common worldwide. They are numbered about 25 thousand.

Scientific classification of flat worms

Flat worms belong to the kingdom of bilateral (symmetrical on both sides) due to some disputes that have arisen when trying to divide flat worms in different groupsScientists refer them to the parafilation group. It includes representatives of a small part of the descendants of the same ancestors.

The structure of the internal organs of a flat worm

The body of flat worms extended and flattened, inside without cavity. That is, all the space is filled with cells. Inside there are layers of muscles, which together with the shell of the worm form a skin-muscular bag.

There are systems of internal organs:

• The digestive system is represented by mouth and blind (no exit) to the intestine. Nutrients come through the mouth, and can be absorbed by the entire surface of the body.
• The nervous system consists of brain gangliy and nerve pillars. Some classes of flat worms have primitive equilibrium organs.
• The excretory system consists of special tubules, but most often the selection occurs its entire body surface.
• The sexual system is represented as women's (ovaries) and male (semenniki) by genitals. Flat worms hermaphrodites.

Differences of flat and round worms

Round worms differ from flat topicsWith cross section, the body has a round shape. Round worms are still called nematodes. Possessing the bilateral-symmetric structure of the body, they have a developed musculature. But the main difference from flat worms is that round have the inner cavity of the body, and flat - no.

Variety of classes of flat worms

Table "Flat Worms" clearly shows the division of the form of classes, which modern science has seven.

Class name	Habitat		Life cycle
Monogenesey (Soskers)	With the help of an attachment disc at the rear end of the worm of monogena, it is attached to the cacks of fish and the skin of amphibians and turtles	Very small, on average no more than 1 mm	For life, the worm has one owner, to which he gets in the form of a free floating larva
Custo-shaped		Length varies from 2.5 to 38 cm	The larvae develop in the body of crustaceans when swallowing the egg. After eating a crustacean water vertebral, an adult part easily from the intestine of the new owner moves to the body cavity, where he lives and breeds
Aspidogastry	Dwell in the bodies of mollusks, freshwater and marine fish	Adult individual rarely reaches more than 15 mm	Several times there are shifts for life cycle Chervey
Trematodes (Soskers)			For life there are several owners. The larva lives at the beginning in which he subsequently dies. Fits inside when swallowing churches (ready to settle in the final owner of the larvae)
Gyrogotilids		From 2 to 20 cm	Hypothetically larvae first develop in the body of the intermediate owner, and only then move into fish. But due to the fact that chimeric fish deep-water, experimental hypothesis is not confirmed by
Tape	The habitat of the flat worms of the intestine of a mammal and a person, to the wall of which they are firmly embarrassed with the head	Can reach sizes up to 10 m.
Rishichny	Basically free-free worms, inhabit fresh and salted water bodies, sometimes in humid soil	The length of the body ranges from microscopic sizes up to 40 cm	A larvae similar to an adult worm comes out of the egg, upholstered among the plankton, until it grows

Crymfish

They are predators who use small invertebrates, arthropods and even large clams. They completely swallow small mining or strong sucking movements tear off her pieces.

The body of worms can independently regenerate. A bright representative is a planaria, which even a small part of the body rebels in a full-fledged individual.

Flat worms in home aquariums

Helmintes can become a big problem for fans of fish breeding in aquariums.

The habitat of flat worms is mainly water. Being alcohol, flat worms can be attached by means of an attachment disc to the surface of the gills and skin of aquarium fish.

Adult worms lay eggs from which larvae leaving on the skin of fish. Gradually, they quarre into the gills, where they grow, reaching sexual maturity.

Some species of flat worms fall into the home aquarium with a soil, alive food. The larvae can be on the surface of algae, on the skin of new fish populated into the aquarium.

• Pseudophyllidea (Lenthec wide). Infection may come if raw, poorly salted fish is present in the diet. In the small intestine of man, Lenthec can live decades, reaching lengths up to 20 m.
• AeniaRhynchus Saginatus. (bovine chain). The habitat of flat worms is a human intestine and cattle. Singing to its walls, Gelmint grows up to 10 m. The larvae can be in others internal organs, in hard-to-reach places (brain, muscles, liver), so it is often impossible to completely get rid of them. The patient has a fatal outcome. Infection occurs when the eggs of helminths in the stomach with insufficiently thermally processed food, from dirty hands.
• Echinococcus (Echinococcus) is often found in dogs and cats, moving from them to the body to man. Despite minor sizes - only 5 mm - the ability of its larvae to form Finns, paralyzing internal organs, is deadly. The larvae is capable of penetrating the respiratory, bone, urinary systems. Reference worms of Echinococci are often found in the brain, liver and other internal organs. A person can easily be infected with larvae allocated with a feet of a dog that apply to wool, and from there to all household items and food.
• The liver lodder is a culprit of cholecystitis, liver colic, disorders of the stomach and intestines, allergies. The habitat of flat worms is mainly a liver of a person and warm-blooded animals, biliary paths. The length of the body of the loser does not exceed 3 cm. A feature is that not only mature individuals, but their larvae are capable of reproduction.

Prevention of Helminty infection

Preventive measures of eggs and larvae of helminths in the human body are as follows:

• It is necessary to thoroughly wash your hands with soap before each meal, after visiting public places, toilet, street, pet-friendly.
• Wash raw vegetables and fruits with warm water with soap.
• Do not eat raw meat and fish.
• Durable heat treatment food, especially meat, fish.
• Pay attention to the timely prevention of melting invasions of pets.
• Regularly, at least once a year, donate the analysis of the feces on the eggs of worms.

Body cover Outside the body is covered with a single-layer epithelium. At the cereal worms, or turbellarium, the epithelium consists of ciliary cells. Saladers, monogenes, cure-shaped and tape worms for most of the life are deprived of a ciliary epithelium (although the cilia cells may occur in larch forms); Their coverings are represented by the so-called tugment, in a number of groups of carrier microwaves or chitin hooks. Flat worms with the tugment are related to the Neodermata group. Flat worms can regenerate 6/7 of their body.

Musculature under the epithelium is a muscular bag consisting of several layers of muscle cells that are not differentiated into individual muscles (a certain differentiation is observed only in the area of \u200b\u200bthe pharynx and genital organs). The cells of the outer muscular layer are focused across, internal - along the annex-ardent axis of the body. The outer layer is called a layer of ring musculature, and the inner - layer of longitudinal muscles.

The nervous system and sense organs The nervous system is represented by nerve nodes located in the front of the body of the worm, cerebral ganglias and the nervous pillars separated from them connected by jumpers. The senses are usually represented by separate skin cilia - the process of sensitive nerve cells. Some free-acting representatives of the type in the process of adaptation to the habitat conditions have acquired photosensitive pigment eyes - primitive organs of vision and equilibrium organs.

The structure of the body bilateral-symmetric, with well-pronounced head and tail ends, a slightly flattened in the dorsovetral direction, in large representatives is greatly flattened. The cavity of the body is not developed (with the exception of some phases of the life cycle of ribbon worms and seashers). Gas exchange is carried out through the entire surface of the body; Breath organs I. blood vessels No missing.

Questions: How many flat worms inhabit in Russia? What are the covers of the body in flat worms? What musculature? What are the senses? Describe a brief body structure as flat fastened? How to breathe? How to breed?

Interesting Facts 1. By digestion, flat worms are able to "learn". A group of scientists made an unusual discovery regarding the abilities of flat worms. It turns out if the planar worms first teach the labyrinth, then grind them in mashed potatoes and give it to eat other worms, then such a labyrinth will go from the first time.

Interesting facts 2. Different kind of worms - schistosomes are inseparable throughout life. The female lives in his pocket in the male all his life.

Interesting facts 3. Almost all types of flat worms can be turned inside out. 4. But even interesting facts about flatwives. For example, flat worms are truly almost immortal. If you cut off the worm of a very small piece of approximately 1/100 of a part of a whole worm, then it is still capable of recovering to a whole body.

Interesting facts 5. On the skin of some planaries living in fresh water, scientists discovered the spectal cells, which are very similar to cutting cells available in intestinal individuals. It turns out that these cells really previously belonged to the intestinal, which later eaten the cilia worms. Crazy cells are not digested. They fall into their skin and serve to perform a protective function and attack.

L J.

The features of the structure of the bilateral symmetry is a single cavity of symmetry divides the body to the left and right half. Development comes from three germinal leaves: Ektoderm, Entoderma and Mesoderm. The third germ leaf appears for the first time during the evolution and gives the beginning of the development of parenchymal cells, filling the gaps between the organs and the muscular system. Left half right half

Features of the structure of the body sizes from 2-3 mm to 20 m. The body is pulled in length and is flattened in the rigorous direction; It has a ribbon or leaf shape characteristic of the presence of developed systems of organs: muscle, digestive (absent from tapes), excretory nervous and sex.

Body cover I. muscular system The cells of the epithelium and muscles are separate education. The skin-muscular bag consists of a single-layer epithelium (in the aquatic forms of the epithelium has cilias) and three layers of smooth muscles: ring, longitudinal and oblique). Some representatives also have spinal abdominal muscles. The movement is ensured by cutting muscles (lossers and tape worms) or cilia of the cover epithelium and cutting muscles (ciliary worms).

The digestive system has two departments - front (mouth, throat) and medium (intestinal branches). The intestine is closed blindly, the rear part of the intestine and the anal hole is missing. Unpained food remnants are removed through the mouth. In ribbon worms, the digestive system is absent (represented by separate digestive cells).

The excretory system is formed by the tubuine system, one end of which begins in the parenchyem by a star-cage with a bunch of cilia, and the other is in the excretory duct. The duct is combined into one or two common channels ending with excretory pores.

Nervous system. Sense organs. It consists of dumping nerve nodes (ganglia) and longitudinal nerve trunks walking along the body and linked by transverse nerve jumpers. Feeling and chemical feeling organs. Free-lived there are bodies of touch and equilibrium.

Liver lobster liver losers, in length typically reaches 3 cm, in width of 1.3 cm .. OpisThorchis detachment lobby losers cause opisthorchosis, the symptoms of the early stage - an increase in liver, allergic reactions and disorders of the gastrointestinal tract; Symptoms late stage - Pain in the back of pain, bile colic, headaches and dizziness, insomnia. Treatment is made by antihelmint, choleretic and enzyme preparations. Also applied electromagnetic radiation High frequency.

The development cycle The life cycles of different clans are different. At the species of the genus Fasciola, development occurs with one intermediate owner ( freshwater snail), and infection of the final owner occurs when swallowing with water or eating with coastal plants Regarding stage - Adolescary. At the species of childbirth opisthorchis and clonorchis, freshwater fish is the second intermediate owner, and the infection of the final owner occurs when eating raw fish with invasive stages. The species of the genus Dicrocoelium intermediate owners serve terrestrial pulmonary snails and ants, and infection of the final owner (usually a herbivore) occurs when eating with grass infected ant.

The bullish chain (solitir) is striking cattle and human, causing Tenarichoz. A bull chain infection is especially common in Equatorial Africa, Latin America, in the Philippines and in some parts of Eastern Europe. The adult part of the bull chain consists of more than 1000 segments and reaches 4-40 meters in length. The laying of the sexual apparatus begins approximately from the 200th segment. Length of mature proglottid mm, width 5-7 mm. Skolex (head unit) is equipped with 4 suckers without hooks (therefore unarmed). Life life of the bull chain in the intestine of a person, if not to take any measures for degelminting, is years. For year, the chain produces ~ 600 million eggs, in a life of ~ 11 billion.

Cycle of development from the intestine of a person (the main owner) segments of the eggs containing eggs. Together with the grass, they fall into the stomach cow (intermediate owner). Six rustic larvae come from eggs, which penetrate the circulatory vessels of the intestines and then into the muscles. In the muscles, the larva turns into the Finns (bubble with the chain head inside). When using poorly processed phinosic meat, a chain head is attached to the intestinal wall and begins to produce segments.

The features of the structure are bilateral symmetric. Dimensions from several micrometers (soil) to several meters (nematodes of coushlot). Have a non-grinded body with a dense cuticle. Firecard partially or fully reduced. The body is filamentous, spindle-shaped, non-varying, round in cross section.

The digestive system is formed by the front, middle and rear intestine. The front intestine is differentiated to the departments: mouth with cuticular lips, throat and esophagus. Average I. rear estate The departments are not divided. The digestive tract ends with anal hole.

The separation system is represented by 1-2 skin glands (modified protonophritia). These are large cells from which two channels are departed on the sides of the cell. In the rear end of the body, the channels end blindly, and in front open to the outer medium separating sometimes.

Nervous system. Feeling organs nervous staircase system. It is represented by head nerve nodes (ganglions), by the incapacity of the nerve ring and several nervous trunks (spinal and abdominal), median transverse jumpers. The senses are represented by signing and chemical feeling authorities. Sea forms have photosensitive receptors. Scheme of the nervous system of Askarida: 1 - robot papillas with tangible endings and innervating them nerves, 2 - Occalaporic ring, 3 - side head ganglia, 4 - abdominal nerve trunk, 5 - side nerve trunks, 6 - ring nerves, 7 - rear gangli , 8 - Sensitive nipples with appropriate nerves, 9 - anal hole, 10 - spinal nerve trunk

Ascaris Askarida Askarida Large round worms, their length can reach 40 centimeters. Most often affect organs gastrointestinal tractcause ascaridosis. A favorite habitat of adult individuals is a small bowel. Askarida biscuit worms. Faces Askarid can per day produce more than 200 thousand eggs. Fertilized eggs from the intestine of a person fall into the soil. They develop larvae. Infection occurs when drinking water from open reservoirs, the use of poorly washed vegetables, fruits, on which there are eggs with larvae. In the human body, the larva commits migration: hitting the intestine, it triggers its walls and falls into the blood flow.

Particularities of the bilateral symmetry of the body. Sizes from 0.5 mm to 3 m. The body is divided into a head blade, a torso and anal hole. Multi-pi-colored heads with eyes, tentacles and mustaches. The body is segmented (external and internal segmentation). The torso contains from 5 to 800 identical segments having a rings. Segments have the same external and internal structure (metamery) and perform similar functions. The metaireral structure determines the high degree of regeneration.

Body cover and muscular system The body wall is formed by a leather-muscular bag consisting of a single-layer epithelium coated with a thin cuticle, two layers of smooth muscles (outer ring and internal longitudinal) and single-layer epithelium of the secondary body cavity. When cutting the ring muscles, the body of the worm becomes long and thin, with a reduction of the longitudinal muscles, it is shortened and thickened.

The body cavity is a secondary one (has an epithelial race). In most body cavities are separated by transverse partitions, respectively, the body segments. Liquid fluid is a hydraulic cooler and internal environment, it participates in the transport of the exchange products, nutrients and sex products.

The digestive system consists of three departments: front (mouth, muscular throat, esophagus, goiter), medium (tubular stomach, middle intestine) and rear (render, anal hole). The glands of the esophagus and middle intestine distinguish the enzymes for digesting food. Suction takes place in the middle intestine.

Circulatory system Closed. There are two vessels: spinal and abdominal, connected in each segment of ring vessels. On the spinal vessel, the blood moves from the rear end of the body to the front, in front of the abdominal. The flow of blood is carried out due to rhythmic cuts in the walls of the spinal vessel and the annular vessels ("heart") in the pharynx area. Blood has many red.

Extraction system of metanefidial type. Methanefridias have the view of the tubes with funnels, two in each segment. The funnel, surrounded by cilia, and convolutions are in the same segment, and short channels opening the outward holes at the adjacent segment.

Nervous system. Sense organs. It is represented by pharmaceutical and subglostic nerve nodes (ganglia), which are connected to the obscalogling nerve ring and the abdominal nervous chain consisting of paired nerve nodes in each segment connected by longitudinal and transverse nerve trunks. Multi-point there are equilibrium and vision organs (2-4 eyes). Most have only olfactory, tactile and photosensitive cells.

The reproduction and development of soil and freshwater forms are mostly hermaphodite. Separations are developing only in certain segments. Seamation internal. Development type - direct. Miscellaneous reproduction is carried out by killing and fragmentation (thanks to regeneration). Sea representatives separately. Development with metamorphosis, larvaehood.

Subcutaneous worm rishta

There are worms living in human blood. These include saintosomes. The main habitat is blood vessels. However, they are able to penetrate into various organs, causing symptoms of defeat gOOD SYSTEM, liver, kidneys.

In the blood there may be larvae of some helminths. For example, there is a spread of them in the body of the intermediate owner. With blood flow, the larvae migrate to various organs, where cysts are fixed and formed, containing adult worms heads. The final owner in the digestive path in the digestive tract is attached to the intestinal wall, giving the beginning of a semi-shine individual.

Flat worms: general characteristics

The body of flat worms can make complex and varied movements.

All flat worms have common features Buildings:

• Outdoor cover is represented by the cuticle. Free-lived individuals are covered with cilia, the surface of the body of worms is usually smooth.
• Under the outer cover there are several layers of muscle fibers.
• There is no body cavity.
• The digestive system has only one hole - the mouth. The intestine ends blindly. Some worms are generally devoid of digestive organs. So, the tape worms, absorbing nutrients with the whole body from the boss of the owner's intestine, they are not needed.
• There is no blood system and blood, as well as respiratory organs.
• The excretory system is represented by a network of tubes that permeate the whole body.
• The nervous system is primitive. Near the pharynx there are several ganglia, from which the nerve trunks connected by jumpers are departed. The senses are formed only at free-lived individuals and some worms at the larval stages of development.

A system that is really well developed is sex. Flat worms - hermaphrodites. The reproduction is possible with the participation of 2 individuals or by self-emptying.

Slacers

The development cycle of trematodes is one of the most complex. From eggs, which came to the external environment, Miracidia come out. In the water, the latter feel comfortable and some time exist as free-lived organisms. The next stage is the introduction of Miracidium in the first intermediate owner. The larva does it with the help of a special cutting machine on the head. The owner usually becomes mollusk.

Their life cycle can occur in several owners and accompanied by natural alternation

Here Miracidia turns into a sporocist, which gives the beginning of the next stage of development cycle - fines. Those in turn are the predecessors of the churches who leave the intermediate owner and again fall into water medium. Next, the development cycle is one of two options. Cerciria is transformed into cysts directly in the external environment (attached to algae) or in the body of the second intermediate owner (mollusk, fish, amphibian).

These are the longest worms with a transparent shell

Infection of the final owner occurs when eating them infected intermediate bodies. The development cycle is completed with the attachment of the head from the cyst to the wall of the intestine and the development of an adult worm. The latter can reach significant sizes (so, the Lenthec is widely growing up to 10 m long).

A man for the losers is the final owner, but for ribbon worms can be intermediate.

What symptoms occur when a man is infected with helminth? The clinic of the disease is due primarily to the fact that the body was amazed. Half-green worms usually live in the intestines, so in the overall picture of the disease prevail symptoms characteristic of digestive disorders: nausea, gas formation, stool disorders, abdominal pain.

Helmintes highlight the products of life, which, falling into the blood, cause poisoning and symptoms of intoxication (temperature rise, fatigue and other). In addition, they are perceived by the immune system as an allergen. Therefore, helminthoses are often accompanied by symptoms. allergic reaction (Sweeping on the skin, itching).