Hydrostatic skeleton, Biology

Hydrostatic Skeleton

The functioning of the hydrostatic skeleton in an animal depends upon the musculature being arranged around an enclosed volume of fluid. After that, contraction of some of the muscles can cause pressure on the fluid that can be transmitted to the rest of the body, in all directions. In annelids, the coelom with the fluid in the coelomic space (or spaces) together along with the surrounding musculature constitute the hydrostatic skeleton. The coelomic fluid has a constant volume. Commonly speaking, contraction of any muscle in the body wall of an annelid would cause an increase in the hydrostatic pressure that in turn would cause stretching of flaccid muscles. In annelids along with circular and longitudinal 'muscles, contraction of one set of muscles is accompanied through stretching of the other. Polychaetes have feebly developed body musculature. The spacious coelom is compartmentalized through transverse septa. Though, there are perforations in the transverse septa which allow continuity of the coelomic fluid among compartments. So in polychaetes the hydrostatic skeleton is not well developed. In oligochaetes, the body musculature is very well developed and the transverse septa do not have the perforations during locomotion. The coelom in the adjoining segments stays mostly isolated. Like the longitudinal muscles of a segment contract, the circular muscles relax and owing to the incompressibility of the coelomic fluid, the segment turns shorter but thicker. Simultaneous protrusion of the setae helps the worm anchor to the substratum. While the reverse happens, that is, when the circular muscles contract, the longitudinal muscles relax, the segments become long and thin, the setae are withdrawn and the body progress forward. That is, the contraction and relaxation activities are localized being limited to a few segments of the body, the wave of contraction and relaxation passing from one end to the other. This results in the animal's progression.

Posted Date: 2/4/2013 2:08:40 AM | Location : United States







Related Discussions:- Hydrostatic skeleton, Assignment Help, Ask Question on Hydrostatic skeleton, Get Answer, Expert's Help, Hydrostatic skeleton Discussions

Write discussion on Hydrostatic skeleton
Your posts are moderated
Related Questions
Define the Single Cell Proteins (SCP)? You may have heard of SCP. What is a single cell protein? Let's find out. The term SCP was coined by Prof. Caroll Wilson (MIT) in 1966. I

Explain in brief Chitinous? A structure which is composed of chitin, a complex carbohydrate composed of linearly arranged Nacetyl-glucosamine units. Chitin is a characteristic

Explain fontan operation and ross operation in heart dieases? Fontan Operation: The Fontan principle involves redirecting the whole systemic return into the lungs bypassing t

Synthesis of fatty acids requires the movement of citrate out of the mitochondria. This occurs under conditions of high levels of acetyl CoA which is needed to stimulate the activi

#questiHow do the non parasitic lampreys interact with other members of their ecosystem in comparison to their parasitic cousinson..

Q. What is Secretary diarrhoea? Secretary diarrhoea: It is a result of active secretion OF electrolytes and water by the intestinal epithelium caused by bacterial and viral inf

The movement  of Na + and glucose  from the lumen  of the intestine  across  the epithelial  cell to the blood  sets up a dissimilarity  in osmotic  pressure  across  the cell. As

when microbial culture must be harvested after giving osmotic stress to analyze osmotolerant genes?

Mountains and their forest ecosystems are regarded as the water towers of the world. A good example is the extraordinarily massive Himalayan Mountains which have shaped the climate

Sinus Perforations  The maxillary antrum can sometimes be inadvertently penetrated. Through careful pre-operative planning using radiographs, including axial scans, this compli