What is nerve net in zoology?
A nerve net consists of interconnected neurons lacking a brain or any form of cephalization. The nerve net is the simplest form of a nervous system found in multicellular organisms. Unlike central nervous systems, where neurons are typically grouped together, neurons found in nerve nets are spread apart.
What is a nerve net and what is its function?
This nerve net allows transmission of information from one part of the animal to another and coordination of simple movements. The stinging organs of cnidarians, nematocysts, discharge without nervous control.
Do humans have nerve nets?
Humans have a very complex nervous system composed of our ‘supercomputer brains’, the high-speed communication highway of our spinal cord, and an extensive network of nerves that spiderweb throughout our bodies.
Is the nerve net continuous?
Reticular theory is an obsolete scientific theory in neurobiology that stated that everything in the nervous system, such as brain, is a single continuous network. The concept was postulated by a German anatomist Joseph von Gerlach in 1871, and was most popularised by the Nobel laureate Italian physician Camillo Golgi.
What is meant by the term nerve net?
: a network of neurons apparently continuous with one another and conducting impulses in all directions also : a primitive nervous system (as in a jellyfish) consisting of such a network.
Does Hydra have brain?
Instead of a brain, hydra have the most basic nervous system in nature, a nerve net in which neurons spread throughout its body.
Which animal has radial symmetry and a nerve net?
A rule of thumb is that animals with radial symmetry (Jellyfish, Anemones, Hydra) have neural nets, which is a general distribution of neurons throughout the body.
How do cnidarians eat?
All cnidarians are carnivores. Most use their cnidae and associated toxin to capture food, although none is known actually to pursue prey. The mouth opens, the lips grasp the food, and muscular actions complete swallowing.
Do cnidarians have a brain?
Cnidaria do not have a brain or groups of nerve cells (“ganglia”). The nervous system is a decentralized network (‘nerve net’), with one or two nets present. They do not have a head, but they have a mouth, surrounded by a crown of tentacles. The tentacles are covered with stinging cells (nematocysts).
Who proposed reticular theory?
Ramón y Cajal opposed the idea that nervous tissue was made up by a network of continuous elements. This ‘reticular theory’ (or ‘reticularism’), which prevailed at the time, was proposed in 1871 by the German anatomist Joseph von Gerlach (1820–96) and was also supported by Golgi, among others.
Which would you find in an animal with a nerve net quizlet?
The simplest animals with nervous systems are the cnidarians (jellyfishes). They have neurons arranged in nerve nets.