Cephalisation - metazoa, Biology

Cephalisation - Metazoa

Bilateral animals when creeping or swimming, have a tendency to keep the same end of the body forward and the same surface down towards the substratum. In such a case the sensory organs and nervous system would also have a tendency to be concentrated at the anterior end. This differentiation of a 'head end' is known as cephalisation'(literal1y head development). Cephalisation has evolved to various degrees in bilateral animals.

2091_Cephalisation - Metazoa.png

                           Figure: Concentration of nervous system in anterior region of a) liver fluke b) Tapeworm c) Planaria

The mouth is usually located at the leading end with which become associated the organs for food capture, as the sensory organs on the head can detect food. Neurons become organized into brain in this region for rapid coordination; longitudinal nerve cords are developed for rapid transmission of information throughout the length of the body. Cephalisation in its most primitive form can be seen in Platyhelminthes.

Posted Date: 1/15/2013 2:28:14 AM | Location : United States







Related Discussions:- Cephalisation - metazoa, Assignment Help, Ask Question on Cephalisation - metazoa, Get Answer, Expert's Help, Cephalisation - metazoa Discussions

Write discussion on Cephalisation - metazoa
Your posts are moderated
Related Questions
Kinds of Matter On basis of its chemical organization, matter id of three categories elements, compounds and mixture An element is composed of obviously, earth similar atoms

Closed Type of Circulatory Systems Some non-chordates, like cephalopods (octopuses, squids), earthworms, polychactes and all vertebrates have a closed circulation along with b

How Campylobacteriosis is caused It is caused by  Campylobacter jejuni, a Gram-negative rod. It is a microaerophillic organism, which means it has a requirement for reduced lev

Q. (a) In droplet infection (i) where do the droplets come from, (ii) what infective agents might they contain? (b) Give two examples of diseases normally spread

Explain about the Reduction Tests - Carbohydrates? These are a group of tests answered by reducing sugars. Since we have already discussed  reducing sugars, you will be able to

Determination Reductive hydrolysis of folic acid produces 4-aminobenzoyl glutamic acid which is determined photometrically after  diazotization and coupling with N-(1-naphthyl)

Q. How does the intensity of simple diffusion differ in relation to the concentration gradient of the moved substance? The higher the concentration gradient of a substance the

Aortic Valve replacement :  The initial steps of the operation have been described earlier. Ascending aorta is cannulated. A single two-stage atrio-venous cannula is inse

Q. What is Acute Aortic Regurgitation? Infective endocarditis, aortic dissection and trauma often produce severe AR. Acute increase in left ventricular end diastolic volume es

The cell cycle is controlled by a cyclically operating set of reaction sequences that both trigger and coordinate key events in the cell cycle • The cell-cycle control system is