OPEN CIRCULATION Meaning and
Definition
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Open circulation refers to a type of circulatory system found in certain invertebrates where the blood or hemolymph is not entirely contained within blood vessels. This system lacks a comprehensive network of vessels and instead relies on open spaces, called sinuses or hemocoel, which are distributed throughout the body. In this type of circulation, blood is pumped by a heart or a specialized organ into these sinuses, bathing the organs and tissues directly. The hemolymph then returns to the heart through openings called ostia.
Open circulation is characterized by its slower and less controlled movement of blood compared to closed circulation systems. However, this type of circulatory system efficiently transports nutrients, hormones, and wastes throughout the body. It also plays a crucial role in the metabolism and temperature regulation of these organisms.
Organisms that possess open circulation include mollusks, arthropods (such as insects and crustaceans), and some non-vertebrate chordates. This system allows them to adapt to various environments and perform specialized functions. For example, in insects, the open circulation system aids in flight by facilitating oxygen delivery directly to the muscles.
Overall, open circulation is a circulatory system where blood is not enclosed within vessels, but instead bathes the organs and tissues directly through sinuses. It provides a vital transport mechanism for nutrients and metabolic products in various invertebrate organisms.
Etymology of OPEN CIRCULATION
The term "open circulation" can have different meanings depending on the context, so it's important to clarify which specific field or concept you are referring to. However, I will try to provide an explanation based on the most common usage in the context of biological circulatory systems.
In biology, the term "open circulation" refers to a type of circulatory system found in certain organisms, such as insects, mollusks, and most other invertebrates. Unlike closed circulatory systems found in humans and some other animals, open circulatory systems do not have a continuous network of blood vessels.
The etymology of "open circulation" can be understood by analyzing the individual words. "Open" comes from the Old English word "ope", which means "not closed or barred". It has its origins in the Proto-Germanic word "upan", meaning "up" or "open".
