Nerve tractA nerve tract is a bundle of nerve fibers (axons) connecting nuclei of the central nervous system. In the peripheral nervous system, this is known as a nerve fascicle, and has associated connective tissue. There are three main types of nerve tracts in the central nervous system: association fibers, commissural fibers, and projection fibers. A nerve tract may also be referred to as a commissure, decussation, or neural pathway.
BrainOrgan central to the nervous systemThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrateanimals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing, and olfaction.
NeuronPrimary cell of the nervous systemA neuron (American English), neurone (British English), or nerve cell, is a cell that is excitable, firing electric signals called action potentials. Neurons form neural networks in the nervous system, mainly in the central nervous system. Neurons receive and conduct impulses.AxonAn axon (from Ancient Greek: ἄξων, romanized: áxōn, lit.'axis'; also called a nerve fiber or fibre) is a long slender projection of a nerve cell or neuron found in most animals that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands.
MyelinMyelin ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon.
Nervous systemIn biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensoryinformation by transmitting signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago.
Nerve fascicleA nerve fascicle is a bundle of nerve fibers belonging to a nerve in the peripheral nervous system. A nerve fascicle is also called a fasciculus. In the central nervous system, the analogous structures are known as nerve tracts. A nerve fascicle is enclosed by perineurium, a layer of fascial connective tissue. Each nerve fiber in the nerve fascicle is also enclosed by a connective tissue layer of endoneurium.
NeuroanatomyNeuroanatomy is a branch of anatomy and neuroscience that studies the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defined nervous systems. Their neuroanatomy is therefore better understood.
SynapseIn the nervous system, a synapse is a structure that allows a neuron to exchange (receive or send) signals with another cell in its immediate vicinity. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons. In the case of electrical synapses, neurons are coupled bidirectionally with each other through gap junctions and have a connected cytoplasmic milieu.
NeurotransmissionNeurotransmission (Latin: transmissio "passage, crossing" from transmittere "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), and bind to and react with the receptors on the dendrites of another neuron (the postsynaptic neuron) a short distance away.
White matterWhite matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain regions. White matter is named for its relatively light appearance resulting from the lipid content of myelin.
Grey matterGrey matter (gray matter in American English) is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries.*As an Amazon Associate I earn from qualifying purchases.