Body wall (t ǐ b ì) is the outermost tissue of some organisms, mainly insects.In the past, many people thought that only insects had body walls, but in fact, some other classes of creatures also had body walls, such as those belonging to CrustaceaDame。It is composed of embryonicEctodermSome undifferentiatedCellsThe skin cell layer and its secretion (epidermis) are formed.Sclerosis of epidermisExoskeletonTo maintain the body shape of insects and host body wall muscles, the body wall also has a protective effect. On the one hand, it can prevent the evaporation of water in the body to maintain the water balance in the body, and on the other hand, it can prevent the invasion of foreign substances.
Body wall can preventInsecticideandFungiThe invasion of substances, therefore, the use of pesticidespestConsider how to destroy the body wall so that the water in the body can evaporate and lose the water balance, and also consider the use of highly permeablesolvent, destroy the middle and upper epidermis of the body wall and the outer epidermisChemistrymoleculeTo enhance the effectiveness of pest control.
Formed by invagination of body wallEndoskeletonIs used to attach the body wall musclemuscle fibersSome form trachea for breathing.The unhardened epidermis plays an important role in the bending and stretching activities of the body. When a part of the new epidermis can be dissolved and absorbed in the process of formation or in the case of starvation, it is also a storage body that supplies raw materials for biochemical synthesis;Other cells can be specialized into various sensory organsGlands, used to receive environmental stimulation and secrete variouschemical compound。Mediate insect behavior.In addition, skin cells also receivehormoneControl and periodicallyto shedandmetamorphosisPostembryonic development.
body wallAlthough it can effectively prevent water loss in the body, it still has a certain permeability to water
The strength of its water permeability is mainly determined by the wax content and wax in the upper epidermis, and the wax and wax amount depend on the silkworm variety, silkworm order,body wallParts and feeds vary
Transparency
Generally, the dermal cells of silkworms contain globular urate crystals, which can reflect light and appear milky whitebody wallOpaque. However, the midline of the silkworm's back, the inner side of the gastropods and other places lack the crystal, which makes them more transparent. Then, when the silkworm is old and ripe,body wallThe uric acid salt crystal in is dissolved and transferred to the blood, making the skin more transparent
In some silkworm varietiesuric acidThe salt content is very low, so the wholebody wallTransparent, like oiled paper, is specially called oil silkworm
According to the investigation, there is no significant difference in the amount of uric acid salt generated in the body of normal silkworm and oil silkworm. The uric acid salt in the dermis of oil silkworm is less, which is due to the lack of substances in the dermis cells of oil silkworm to absorb uric acid salt crystals, so that the uric acid salt in the dermis of oil silkworm is very little, showing the characteristics of oil silkworm
Physiological function
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Supporting role
The larvae of the silkworm are called "boneless worms", butbody wallBut it has the skeletal function of vertebrates, like other insects,body wallIt is the attachment point of muscles, which then fix and support various organs and tissues to maintain a certain body shape.
Protective effect
body wallIt is the outermost tissue of the silkworm, and has a certain tenacity, which can protect organs and tissues in the body
Prevent pathogen invasion
body wallToughchitinIt also contains wax layer and liponitrile layer, which has great tolerance to the dissolution of pathogens. Bacteria, viruses and protozoa can not be integrated frombody wallInvasion into the body can only be transmitted through trauma and eating
Fatty acids contained in the wax layer, especiallybitterandacetic acidIt is one of the reasons why the silkworm body is resistant to fungal infection. Because of the different thickness of the wax layer in different silkworm varieties, the difficulty of fungal infection in different silkworm varieties is different
Prevent excessive water dissipation in the body
body wallBecause of the wax layer, it can prevent the excessive diffusion of water in the silkworm body and maintain the balance of water metabolism in the body
The body wall is where the sense organs are located
To participate in the external exchange of information is to rely on the sensory organs on the body surface
