Hemolymph

The hemolymph occurs in some animal groups before as a blood substitute. A highly developed respiratory system allows an almost complete reduction of the vascular system. This phenomenon can be observed in some arthropods, such as crustaceans ( gill breathing system) or insects ( tracheal ). In these there is a fusion of the secondary body cavity ( coelom ) and the primary body cavity to the so-called Mixocoel. In Mixocoel are the organs that are lapped by a usually colorless liquid. As an open circulatory system is present, there will be a blending of the Mixocoelflüssigkeit with the original blood. Therefore, the hemolymph is often referred to as " blood of Insects" or "blood crustaceans ".

Function

The hemolymph containing no red blood cells and is similar to a mixture of blood plasma and lymph. " The most colorless liquid " is, among other transporter of " nutrients, hormones and metabolites ." The hemolymph provides temperature compensation and has " in the defense against pathogens or to wound closure, " a similar function as the human blood.

Hämolymphtransport

Generally

The heart is a very much shortened tube, which is located in a dorsal part of the body cavity, the Perikardialsinus. The haemolymph occurs by segmental, side lying ostia ( openings with valves ) in the heart of one which pushes them through contraction of striated cardiac muscle in a system of open and closed arteries.

Sooner or later leads the hemolymph in the Mixocoel. There are no veins that hemolymph penetrates through to the resulting vacuum in the heart through the ostia back to the heart. In very small representatives of arthropods it even comes to a complete involution of the blood circulatory system and altered function of the hemolymph.

In Crustacea

The hemolymph is also pressed in crustaceans from the heart through arteries into Mixocoel. There, the oxygen-poor blood in hemolymph spaces that are bounded by connective tissue septa accumulated. From there, it penetrates into the gills and is enriched with oxygen and passed through the vessels Perikardialsinus.

In insects,

The heart is in the abdomen and the insect is tubular. From the heart of a cephalad subsequent aortic pulls (similar to dorsal vessel of the annelid ). The contraction of the striated annular heart muscle causes a progressive narrowing from back to front of the heart lumen. Here, the ostia close. Flap-type valves in the heart muscle to prevent the backflow of the blood substitute. The haemolymph occurs by the systole of the heart and flows through the Mixocoel, partly in discrete tracks, and collects again in Perikardialsinus. By the ostia the hemolymph reaches back to the heart. As an alternative to a tubular heart can take place, the pumping motion by a telescoping of abdominal segments, it can also be performed in addition to the heart leg or wing heart.

The hemolymph of many insects contain the disaccharide trehalose.