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when the circular muscles contract, the longitudinal muscles relax, the segments become long and thin, the setae are withdrawn and the body progress forward.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

What are the main human degenerative diseases, Q. What are the main human d...

Q. What are the main human degenerative diseases? The major human degenerative diseases are divided into three groups, neoplastic diseases and degenerative diseases of the nerv

Morphological changes - floral induction, Morphological Changes - Floral In...

Morphological Changes - Floral Induction Some of the morphological changes that accompany floral induction are: Change in the shape of meristem, Increase in the ra

Osmoregulation in terrestrial environment, Osmoregulation in Terrestrial En...

Osmoregulation in Terrestrial Environment  Earlier you have learnt about osmoregulation in aquatic environment. In this section, we shall study how the terrestrial animals cop

Meiosis, How do meiosis do in developing of new varieties of crops

How do meiosis do in developing of new varieties of crops

Diseases, what are the sources of infection (human, animal and non-living r...

what are the sources of infection (human, animal and non-living reservoirs), the routes of transmission (way in which the infection spreads) and different ways in which micro-organ

Blood protozoan and ricketsial diseases - babesiosis, B a b e s i o ...

B a b e s i o s i s It is also known as red water disease or cattle tick fever and is characterized by fever, intravascular haemolysis, acute anaemia and haemoglobinur

Food gathering and hunting , Food Gathering and Hunting : Food Gatherin...

Food Gathering and Hunting : Food Gathering and Hunting In order to live, man needed to eat and to protect himself from the weather and animals.  For both purposes he found it

What are the symptoms of acute pericarditis, Q. What are the Symptoms of ac...

Q. What are the Symptoms of acute pericarditis? Chest Pain Chest pain is the most important symptom. It is retrosternal in location and patient usually locates the site o

Nutrient absorption, Nutrient Absorption Except for carbon, oxygen and...

Nutrient Absorption Except for carbon, oxygen and hydrogen which are provided by CO 2 and water, all the other elements essential for plants are provided by the soil. Hence,

Gas transportation systems in animals, Q. Oxygen comes from the environment...

Q. Oxygen comes from the environment and carbon dioxide in the end returns to the environment. How do small animals solve the problem of taking away and bringing these molecules fr

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