Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Platyhelminthes - Nervous Systems
Among Platyhelminthes, you will observe that turbellarians have a brain and three to five pairs of longitudinal nerve cords extending from the brain to the posterior end. They are positioned along dorsal, lateral and ventral aspects. The cords are connected together through means of commissures. The commissures are in turn connected to a sub-muscular nerve plexus.
Figure: Planarian flatworms have a ladder-type nervous system. Cerebral ganglia in the head region serve as a simple brain and, to some extent, control the rest of the nervous system.
So, the system is not only sunk deeper into the sub-muscular position, but it does not correspond to the real primitive plexus at all. The motor and association neurons are mainly confined to the brain and the cords all along their periphery surrounding the central neuropile. One pair of these longitudinal cords becomes conspicuous, the others tending to become weaker finally disappearing thus giving rise to the typical ladder such as nervous system. With the development of the central nervous system, movements become more co- ordinate. Parts of the animal can keep spontaneous movements and show co- ordination of responses in most species of this group, just only if it contains portion of the nerve cord. The brain appears to have started exerting a dominating affect in this group.
Q. How does photosensitivity in annelids, cnidarians and worms differ from insects, cephalopods and vertebrates? In the first mentioned group of animals there are photoreceptor
Q. What are the major mineral salts responsible for the cellular osmotic regulation? The main ions that act in the regulation of the osmotic pressure in tissues and cells are t
Vulvovaginal candidiasis Vulvovaginal candidiasis is not sexually transmitted, but is often found incidentally in women with STIs. Many remedies are available for vulvovaginal
Explain the Transcription Factor of Zinc? Zinc is an important structural component of DNA- binding proteins also known as 'transcription factors'. These transcription factors
Explain Hazard identification Hazard identification is "the identification of biological, chemical and physical agents capable of causing adverse health effects and which m
the main excretory system in lower animals
Forests, grasslands and wetland protect landscapes against erosion floods and landslides through the binding action of plant roots. The root systems of plants hold soils in place,
Q. What are the main prophylactic measures against malaria? The major preventive measures against malaria are the elimination of the treatment of infected people, vector mosqui
Define effect of dietary fibre expect physiological effects? In addition to all the physiological effects mentioned above, dietary fibre may exert other effects. Acetate and pr
Explain the Membrane Equilibria? A semipermeable membrane used to separate two liquid phases can, in principle, be permeable to certain species and impermeable to others. A mem
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd