The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body.
In geometry, a coordinate system is a system which uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space.
Animals are multicellular, eukaryotic organisms of the kingdom Animalia.
The Nervous System, Part 1: Crash Course A&P #8 by CrashCourse
The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events.
The Nervous System In 9 Minutes by CTE Skills.com
Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago.
Nervous tissue or nerve tissue is the main tissue component of the two parts of the nervous system; the brain and spinal cord of the central nervous system, and the branching peripheral nerves of the peripheral nervous system, which regulates and controls bodily functions and activity.
In vertebrates it consists of two main parts, the central nervous system and the peripheral nervous system.
In the vertebrate spinal column, each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage, the proportions of which vary according to the segment of the backbone and the species of vertebrate.
The CNS consists of the brain and spinal cord.
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column.
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.
The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body.
An axon, is a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron's cell body.
Nerves that transmit signals from the brain are called motor or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory or afferent.
Spinal nerves serve both functions and are called mixed nerves.
The PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems.
The gastrointestinal tract is an organ system within humans and other animals which takes in food, digests it to extract and absorb energy and nutrients, and expels the remaining waste as feces.
Somatic nerves mediate voluntary movement.
The autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems.
Autonomic is derived from Greek autos 'self' + nomos 'law' and broadly means self-governing.
Organs are collections of tissues with a similar function.
The sympathetic nervous system is activated in cases of emergencies to mobilize energy, while the parasympathetic nervous system is activated when organisms are in a relaxed state.
The enteric nervous system functions to control the gastrointestinal system.
Both autonomic and enteric nervous systems function involuntarily.
Nerves that exit from the cranium are called cranial nerves while those exiting from the spinal cord are called spinal nerves.
Cranial nerves are the nerves that emerge directly from the brain, in contrast to spinal nerves.
At the cellular level, the nervous system is defined by the presence of a special type of cell, called the neuron, also known as a "nerve cell".
A neuron is an electrically excitable cell that processes and transmits information through electrical and chemical signals.
Neurons have special structures that allow them to send signals rapidly and precisely to other cells.
They send these signals in the form of electrochemical waves traveling along thin fibers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses.
In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another neuron.
A cell that receives a synaptic signal from a neuron may be excited, inhibited, or otherwise modulated.
The connections between neurons can form neural circuits and also neural networks that generate an organism's perception of the world and determine its behavior.
Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information, or the environment.