basic nerve cell in centeral nervos systemname

The CNS includes the brain and spinal cord. The nervous system is comprised of two major parts, or subdivisions, the central nervous system (CNS) and the peripheral nervous system (PNS). The central and peripheral nervous systems Glia cells are found within tissues and are not excitable but help with myelination, ionic regulation and extracellular fluid.įigure 2. After the brain has processed the information, impulses are then conducted from the brain and spinal cord to muscles and glands, which is called motor output. The data is then processed by way of integration of data, which occurs only in the brain. These nerves conduct impulses from sensory receptors to the brain and spinal cord. These neurons operate on excitation or inhibition, and although nerve cells can vary in size and location, their communication with one another determines their function. The nervous system is composed of excitable nerve cells (neurons) and synapses that form between the neurons and connect them to centers throughout the body or to other neurons. Sensory input is when the body gathers information or data, by way of neurons, glia and synapses. The nervous system has three main functions: sensory input, integration of data and motor output. The Central and Peripheral Nervous Systems Watch this video of biologist Mark Kirschner discussing the “flipping” phenomenon of vertebrate evolution. There is debate among evolutionary biologists as to whether these different nervous system plans evolved separately or whether the invertebrate body plan arrangement somehow “flipped” during the evolution of vertebrates. One interesting difference between the nervous systems of invertebrates and vertebrates is that the nerve cords of many invertebrates are located ventrally whereas the vertebrate spinal cords are located dorsally. While there is great diversity among different vertebrate nervous systems, they all share a basic structure: a CNS that contains a brain and spinal cord and a PNS made up of peripheral sensory and motor nerves. Sweeney, NOAA credit f: modification of work by NIH)Ĭompared to invertebrates, vertebrate nervous systems are more complex, centralized, and specialized. (credit e: modification of work by Michael Vecchione, Clyde F.E. In (f) vertebrates, the brain and spinal cord comprise the central nervous system, while neurons extending into the rest of the body comprise the peripheral nervous system. Mollusks such as squid and (e) octopi, which must hunt to survive, have complex brains containing millions of neurons. In addition to a brain, (d) arthropods have clusters of nerve cell bodies, called peripheral ganglia, located along the ventral nerve cord. In animals exhibiting bilateral symmetry such as (c) planarians, neurons cluster into an anterior brain that processes information. In (b) echinoderms, nerve cells are bundled into fibers called nerves. In (a) cnidarians, nerve cells form a decentralized nerve net.

Octopi may have the most complicated of invertebrate nervous systems-they have neurons that are organized in specialized lobes and eyes that are structurally similar to vertebrate species.įigure 1. Nervous systems vary in structure and complexity. These ganglia can control movements and behaviors without input from the brain.

It contains a brain, ventral nerve cord, and ganglia (clusters of connected neurons). The insect nervous system is more complex but also fairly decentralized. Others, like jellyfish, lack a true brain and instead have a system of separate but connected nerve cells (neurons) called a “nerve net.” Echinoderms such as sea stars have nerve cells that are bundled into fibers called nerves.įlatworms of the phylum Platyhelminthes have both a central nervous system (CNS), made up of a small “brain” and two nerve cords, and a peripheral nervous system (PNS) containing a system of nerves that extend throughout the body. Some organisms, like sea sponges, lack a true nervous system. Nervous systems throughout the animal kingdom vary in structure and complexity, as illustrated by the variety of animals shown in Figure 1.

Compare the functions of different types of glial cells.

List and describe the four main types of neurons.

List and describe the functions of the structural components of a neuron.

Differentiate between the central and peripheral nervous systems.

Differentiate between the nervous systems of different animals.

Basic nerve cell in centeral nervos systemname