What is hemolymph? Composition and function of hemolymph

Blood and lymph in the human body perform important functions to maintain breathing and immunity. However, not all animals have these fluids separated, which is explained by the structure of the body and the simplicity of the organization. Such organisms include representatives of the type Arthropods (insects, spiders, crustaceans) and mollusks. They are characterized by the presence of hemolymph, which has much in common with blood in composition and functions.

Hemolymph - what is it?

For animals such as arthropods or mollusks, an unclosed circulatory system is characteristic . This means that the fluid that circulates through the vessels is thrown into the body cavity and washes all tissues of the organs. This liquid was called hemolymph, t. It combines the functions of blood and lymph.

What is hemolymph in insects and molluscs? It is a colorless, bluish or greenish liquid that is responsible for delivering nutrients to organs and tissues, for metabolic metabolism and immune response when a threat of the disease develops.

The hemolymph of invertebrates also contains uniform elements of the same species, unlike human blood and other evolutionarily developed organisms. These cells are called hemocytes, and they can differ from each other in structure, form and function.

Composition of hemolymph

What is hemolymph from the chemical point of view? The composition of this solution is rather complicated. He performs several functions at once in the body of invertebrate insects. Hemolymph has a neutral or slightly acidic medium, which is maintained by the anions of certain acids. From 75 to 90% of the total solution is water, and the rest of the volume is formed elements and other solutes.

The ion composition of the hemolymph is also varied. It contains cations of sodium, potassium, magnesium and calcium. Of the anions, the most important is chlorine, as well as the residues of phosphoric and carboxylic acids. The content of all ions is variable and depends on the age and stage of development of the organism. For example, in terms of the content of chlorine anions, it is possible to distinguish the insect larva from an adult.

Of the organics in the hemolymph are proteins, fats and carbohydrates. Carbohydrates and proteins come with food through the digestive system, and the content of glucose and fructose depends on the amounts of nectar used.

In 100 ml of hemolymph contains 1-5 g of protein. Proteins play an important role in the life of the body, so they are transported with a current of fluid to the organs and tissues. If hemolymph studies are performed, up to 30 different protein fractions can be isolated, and their number depends on the sex of the organism and age.

Lipids enter the hemolymph from the intestine and fatty body, and in the latter they accumulate throughout life. The content of fats varies, and most of them are esters of glycerol and fatty acids - glycerides. That's what hemolymph is in terms of chemistry.

Functions of hemolymph

What is hemolymph and what functions does it perform in the body of invertebrates?

1. The trophic function, which consists in feeding the tissues and organs, as well as the transport of substances through the body.
2. Metabolic function, when from the tissues in the hemolymph enters the metabolic products and are discharged through the excretory system.
3. Immunological function. It is supported by some types of hemocytes, which are on the surface of the organs.
4. Protective function. The hemolymph of some arthropods and molluscs contains poisons or other toxic substances that protect them from predators.

Form Elements

What is hemolymph in biology? This solution, which contains not only dissolved substances, but also specialized cells - hemocytes. There are 7 types of hemocytes, the main function of which is the immune response to the appearance of antigens. Formed elements form special phagocytic structures on the surfaces of tissues, which act as lymph nodes of vertebrates.