Blood and lymph in the human body perform important functions in maintaining respiration and immunity. However, not all animals have these fluids separated, which is explained by the structure of the body and the simplicity of organization. Such organisms include representatives of the phylum Arthropods (insects, spiders, crustaceans) and Mollusks. They are characterized by the presence of hemolymph, which has much in common with blood in composition and function.
Hemolymph - what is it?
Animals such as arthropods or molluscs are characterized by an open circulatory system. This means that the fluid that circulates through the vessels is thrown into the body cavity and washes all the tissues of the organs. This fluid is called hemolymph, because. it combines the functions of blood and lymph.
What is hemolymph in insects and molluscs? It is a colorless, bluish or greenish liquid, which is responsible for the delivery of nutrients to organs and tissues, for metabolic metabolism and the immune response when there is a threat of developing a disease.
The hemolymph of invertebrates also contains uniform elements of the same species, unlike human blood andother evolutionarily developed organisms. These cells are called hemocytes, and they can differ from each other in structure, shape and function.
Hemolymph composition
What is a hemolymph from a chemical point of view? The composition of this solution is quite complicated, because. it performs several functions at once in the body of invertebrate insects. The hemolymph has a neutral or slightly acidic environment, which is maintained by the anions of certain acids. From 75 to 90% of the total solution is water, and the rest is formed elements and other dissolved substances.
The ionic composition of the hemolymph is also diverse. It contains sodium, potassium, magnesium and calcium cations. Of the anions, chlorine, as well as the residues of phosphoric and carboxylic acids, is of the greatest importance. The content of all ions is not constant and depends on the age and stage of development of the organism. For example, by the content of chlorine anions, one can distinguish an insect larva from an adult.
From 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 amount of nectar consumed.
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 fluid flow to organs and tissues. If you conduct research on hemolymph, you can select up to 30 different protein fractions, and their number depends on the sex of the organism and age.
Lipids enter the hemolymph fromintestines and fat body, and in the latter they accumulate throughout life. The fat content varies, and most of them are esters of glycerol and fatty acids - glycerides. That's what hemolymph is in terms of chemistry.
Hemolymph functions
What is hemolymph and what functions does it perform in the body of invertebrates?
- Trophic function, which consists in nourishing tissues and organs, as well as transporting substances throughout the body.
- Metabolic function, when metabolic products enter the hemolymph from tissues and are excreted through the excretory system.
- Immunological function. It is supported by some types of hemocytes that are on the surface of organs.
- Protective function. The hemolymph of some arthropods and molluscs contains poisons or other toxic substances, which protects them from predators.
Uniforms
What is hemolymph in biology? This is a solution in which there are 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 perform the function of the lymph nodes of vertebrates.
