Contribution to the neurohaemal organs in pterygote insects.

In this review a comprehensive account of anatomy and various cell types occurring in the neurohaemal organs in Pterygote insects has been given. The chemical nature and composition of neurohaemal secretions and the mechanisms of liberation of neurosecretory material (NSM) from neurohaemal organs (NHO) have been described. Also the effects of neurhaemal secretions on diuresis, feeding and growth, heart beat, pigmentation of cuticle, carbohydrate metabolism, oocyte development and respiratory metabolism have been incorporated.