Imaginal discs, Biology

Imaginal Discs

In the holometabolous larva, there are two cell populations:

(1) The larval cells that are used for the larval structures and

(2) The imaginal disc and the histoblasts that are present in clusters, awaiting the signal to differentiate.

Imaginal discs do not take place in the nymphs and larvae of hemimetabolous insects. The imaginal discs or buds are actually rudiments of future organs of the adult, like mouth parts, wings, antennae, walking legs, and internal organs etc. Figure displays the imaginal discs in the larva and pupa of a fly (Musca). These discs develop directly from the eggs and remain nonfunctional during the larval stages. During the pupal stage they grow in size and differentiate to form adult structures which remain collapsed and folded. While the reorganization is completed the pupa moults to set free the adult or imago. Once the adult or imago blood is pumped into this collapsed structure it causes them to unfold and inflate. Furthermore chitin is deposited on then to harden them.

 

2091_Imaginal Discs.png

Figure: Imaginal Discs

Posted Date: 1/30/2013 7:09:49 AM | Location : United States







Related Discussions:- Imaginal discs, Assignment Help, Ask Question on Imaginal discs, Get Answer, Expert's Help, Imaginal discs Discussions

Write discussion on Imaginal discs
Your posts are moderated
Related Questions
Shifting cultivation - Degradation of Ecosystem This method of cultivation is practised all over the globe, but is more prevalent in the tropical countries. In this practice a

Explain Defensive Proteins These proteins protect against diseases. Antibodies are the example of defensive proteins. These  combat bacteria and viruses. Also, immunoglobulins,

How different are the concepts of action potential, resting potential and excitation threshold concerning neurons? Action potential is the maximum positive voltage level achiev

HYPOTHALAMUS - Hypothalamus develops from the ectoderm of the embryo. Location and Structure. It lies below or inferior to the thalamus. The hypothalamus is connected to t

Define Estimation of Blood Thiamin Levels - Thiamin Status? The levels of free thiamin and its phosphoesters in whole blood and erythrocytes are measured using high- performanc

The metabolism of phenylalanine will now be taken in some detail, as two inborn errors of metabolism are known which affect this pathway. The Phenylalanine is 1st hydroxylated by p

Human respiration Human beings are adopted for terrestrial mode of life. They conduct pulmonary respiration. This system consists of external nostrils, nasal cavities, pharyn

Define Risk management Risk management is defined  for the purposes of the Codex Alimentations Commission as  "the process, distinct from  risk assessment,  of weighing polic

identify 7 speccific ways in which you can diversify carbon-containing compounds

Q. What are the features of hnRNA? Heterogeneous nuclear RNA (hnRNA) - Primary precursor mRNA transcript made in eukaryotic nucleus are called 'hnRNA,' an abbreviation for 'het