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when the circular muscles contract, the longitudinal muscles relax, the segments become long and thin, the setae are withdrawn and the body progress forward.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 Nutrition Screening Initiative (NSI)? (NSI) tries to identify basic risk factors - inappropriate food intake, poverty, social isolation, disability, acute / chronic dise

Why is iodine important for human beings? Iodine is a fundamental chemical element for the proper functioning of the thyroid since it is part of the hormones produced by this g

Explain exotic species? Describe with the help of two examples how the exotic species disturb the native species of an ecosystem ?

Are protozoans presenting contractile, or pulsatile, vacuoles easily found in fresh or in salt water? Fresh water is the less concentrated of solutes than sea water and it (fre

Penicillin, discovered by the Scottish doctor Alexander Fleming, in 1928, is a drug that inhibits enzymes essential for the synthesis of peptidoglycans, a constituent of the bacter

Q. What is Constipation? Constipation is irregular, infrequent or difficult passage of faeces. It is the most common physiological disorder of the alimentary tract. It is chara

Define Laser Tweezers Technology? In addition to above said classical methods, advance technologies can be used for obtaining pure cultures. Laser tweezers technology is useful

PHYLUM ARTHROPODA Definition and Introduction Bilateral  and protostomial eucoelomate  eumetazoa with metamerically  segmented  and each  segment bearing a pair  of  join

Which of the following results from the elimination of the sliding clamp? A. DNA polymerase will no longer be processive and will fall off the double helix after synthesizing

#Is GMO food good as the prospective of the ethic values of the society?..