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
Explain the importance of parent material Part of  these weathered minerals are transported  away by volcanoes, wind, water, ice, and waves etc. These very factors transport th

What is the relation between the concepts of chromatin and chromosome? Are euchromatin and heterochromatin part of chromosomes? Every filament of chromatin is a complete DNA mo

what is the function of the tongue in the digestive system?

What is Vacuole ? Another structure found only in plant cells is the large central vacuole. The vacuole stores enzymes and waste products, in addition to providing the turgor p

Define Nutritional Status of the Elderly? Nutritional risk factor is defined as "characteristic or occurrence that increases the likelihood that an individual has or will have

Explain the uses of hydrocolloids In particular, hydrocolloids can provide water for increasing the flexibility (plasticizing) of other food components. These can also affect i

DNA can be divide into fragments using restriction enzymes.    (a) Outline the technique used to separate these fragments.    (b) What property of the DNA f

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Explain Balanus The realised niche of Balanus is the same as its fundamental niche  Lower limits:   as for fundamental niche. Upper  limits: as for fundamental niche

Trans Myocardial laser re vascularisation (TMLR) :  Patients who have severe angina and diffuse coronary artery disease with no graftable vessels are at limes subjected to TMLR. I