Annelids - hormones in growth and reproduction, Biology

Annelids - Hormones in Growth and Reproduction

Studies on polychaetes have displayed that the endocrine glands play a key role in growth and reproduction. In addition to the brain neurosecretory cells, we observe that in annelids there is an infracerebral gland. This is situated in close association along with the brain immediately beneath or behind it. The infracerebral gland has its own secretory cells. In addition, the neurosecretory cells of the brain comprise their fibre terminations in the brain, close to the infracerebral gland, or even passing into the gland. Nereis and Nephthys are examples. The polychaetes are able of rapid growth when young, with proliferation of new segments. They are also able of extensive regeneration. However growth rate and regenerative ability decline along with age. An interesting phenomenon in polychaetes is epitoky. This occurs during sexual maturation in some Nereids. Sexual maturation in them is accompanied by changes in specific regions of the body. The changes involve enlargement of parapodia and development of modified chaeta. The animal is transformed into heteronereid phase, adapted for rapid swimming and sexual swarming.

Posted Date: 2/4/2013 8:03:48 AM | Location : United States







Related Discussions:- Annelids - hormones in growth and reproduction, Assignment Help, Ask Question on Annelids - hormones in growth and reproduction, Get Answer, Expert's Help, Annelids - hormones in growth and reproduction Discussions

Write discussion on Annelids - hormones in growth and reproduction
Your posts are moderated
Related Questions
Accidents in Industry Workplace It is a hard fact to bear in mind that accidents in industry workplace are to be avoided or discarded and efforts in this direction has been in

Regeneration - Root and Shoot Morphogenesis Higher plants have three kinds of regenerative activities; All plants possess inherent ability to regenerate lost parts. Fo

Define Pasteurization and Sterilization - thermal processing? Pasteurization: Pasteurization is a mild heat treatment to kill part of the microorganisms present in food

Urea is known to denature proteins Based on the structure of urea, how do you think this occurs?

Herbicide tolerant crops (HTC) Increased use of the herbicides plant is tolerant to (describes ecological impact eg toxic residues in soil, runoff into waterways) Ther

Cystic fibrosis (CF) is caused by a variety of mutations in the CFTR gene. Imagine you have identified a new single-base pair mutation (A→T) in an exon of the CFTR gene. You wish t

State the concespts of soil- pedology and edaphology In the last two centuries of scientific study, two concepts or approaches to the study of soil have evolved.  One called  p

Explain the Obligatory Losses of Nutrients? Obligatory losses of nutrient are defined as 'the losses that occur when an individual is put on a diet free of that nutrient'. For

Anaphase This  phase is of shortest duration. It  begins  with  a sudden  separation  of the two chromatids of each   due  to splitting   of its centromere and  then a slow mov

What is the mRNA sequence to this DNA sequence : Guanine, cytosine, adenine, adenine, thymine, guanine