Hydrostatic skeleton, Biology

Assignment Help:

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when the circular muscles contract, the longitudinal muscles relax, the segments become long and thin, the setae are withdrawn and the body progress forward.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.


Related Discussions:- Hydrostatic skeleton

Zoology, why protozoass dont have vaccines esp. plasmodiums

why protozoass dont have vaccines esp. plasmodiums

Define iodothyronine deiodinases - functions of selenium, Define Iodothyron...

Define Iodothyronine Deiodinases - functions of selenium in humans? Another group of selenoproteins are the iodothyronine deiodinases essential for the conversion of thyroxine

What are the main events of the first mitotic period, What are the main eve...

What are the main events of the first mitotic period? The first mitotic period is prophase. During prophase the following events happen: migration of each centriole pair (centr

Eubiont, Eubiont The origin of true life , eubiont from a pmtobiont inv...

Eubiont The origin of true life , eubiont from a pmtobiont involves the acquisition of three major features: 1) assembly of phospholipids and proteins into a cell membrane f

Which is the kind of nitrogen waste birds produce, Q Which is the kind of n...

Q Which is the kind of nitrogen waste birds produce? Why does this feature, besides being an adaptation to the terrestrial environment, also mean an adaptation to flight? Birds

What is sick sinus syndrome, Q. What is Sick Sinus Syndrome? Ans. ...

Q. What is Sick Sinus Syndrome? Ans. When a slow resting pulse fails to accelerate normally with exercise, it has been labeled chronotropic incompetence, however, there i

Dimensions of the cells, On a given microscope, the numerical aperture of t...

On a given microscope, the numerical aperture of the objective is 1.5. The microscope is provided with a filter that selects a wavelength of 500 nm. What is the limit of resolution

Explain about the celiac disease, Explain about the Celiac Disease? Cel...

Explain about the Celiac Disease? Celiac disease (also called gluten enteropathy) is an intestinal disorder that results from an abnormal  immunological reaction to gluten. u p

Explain about the microcolony deft, Explain about the Microcolony DEFT? ...

Explain about the Microcolony DEFT? It allows determination of viable cells. Food homogenate is filtered through a DEFT membrane and then placed on the surface of appropriate c

Zonation in the lake biome, Q. Zonation in the lake biome? Precipitatio...

Q. Zonation in the lake biome? Precipitation that does not evaporate or penetrate the soil remains on the soil surface resulting in run off which flows down from the mountains

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd