Open type of circulatory systems, Biology

Open Type of Circulatory Systems

Several non-chordates have thus an open type of circulation - a system in which blood pumped by the heart empties through an artery into an open sinus filled with blood which lies between the ectoderm and endoderm. The blood filled space is considered to as haemocoel, particularly in arthropods. The fluid contained within the haemocoel, referred to as haemolymph or blood, is not circulated by capillaries but bathes the tissue directly. Figures show the organisation of the main vessels from two groups of non- chordates having open circulation, a Cray fish and a bivalve mollusc.

115_Open Type of Circulatory Systems.png

Figure: Invertebrate circulations (A) simplified diagram of the circulation in the crayfish, (B) Simplified diagram of the circulation in bivalve mollusc.

In several animals the haemocoel is large and constitutes 20 - 40% of body volume. In contrast, chordates along with a closed circulation contain a blood volume of 5 - 10% of the total body volume. Open circulatory systems have low pressures; seldom exceeding 5 - 10 mm Hg. Animals that have an open circulation generally have only limited capability to alter the velocity and distribution of blood flow. As a result, in bivalve molluscs and other animals that have an open circulation and use blood for gas transport, change in oxygen uptake is slow and rate of oxygen transfer is low per unit weight. In other words, their metabolism is extremely low, Inseots have, however, avoided this problem by evolving a tracheal system where gas transport to tissues occurs direct through air filled tubes or tracheae that bypass the blood. Accordingly, although insects have an open circulation, they have greater metabolic rate.

Posted Date: 2/4/2013 5:59:01 AM | Location : United States







Related Discussions:- Open type of circulatory systems, Assignment Help, Ask Question on Open type of circulatory systems, Get Answer, Expert's Help, Open type of circulatory systems Discussions

Write discussion on Open type of circulatory systems
Your posts are moderated
Related Questions
Osmoregulation in Marine Non-Chordate Metazoans Studies on the osmotic pressure of body fluids of marine organisms have displayed that their internal osmotic pressure is more

Q. What is gastrulation? How during gastrulation are the first two germ layers formed? What are these germ layers? Gastrulation is the process through which a portion of the bl

Define Overall positive health Effect of Carbohydrate? Non-glyceinic carbohydrates including non-starch polysaccharides are beneficial for the functions and physiology of gastr

What is the relationship of hydrogen ion concentration in tomato juice relative to lemon juice and to pure water? Be as quantitative as you can (i.e., use numbers to describe the m

Viral haemorrhagic fevers (VHF) Viral haemorrhagic fevers (VHF) are caused by a diverse group of viruses belong to the families Arenaviridae, Bunyaviridae, Filoviridae and Fla

Structural Features of Viruses Size of Viruses Virus particles vary widely in size. The smallest viruses e.g. virus of foot and mouth disease  measuring about 20  mill mic

Issues Impacting Health and Development Poverty and malnutrition are the leading causes of high maternal and child mortality rates in developing countries. Together, they seri

Explain Entecavir  Entecavir  (Baraclude) taken orally once a day as monotherapy appears to be superior to lamivudine for patients with chronic HBV infection, but susceptibili

Q. Can you define P-Waves? Changes in P-wave morphology have been well described in resting tracings and are very useful in identifying right and left sided hemodynamic alterat

There are several methods by which a disease-causing organism can be transferred from the reservoir to the host organism. Direct contact : Disease - causing organism may be tr