Central Nervous System- the part of the nervous system which in vertebrates consists of the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, and which coordinates the activity of the entire nervous system.
Peripheral Nervous System- The portion of the nervous system that is outside the brain and spinal cord. The nerves in the PNS connect the central nervous system to sensory organs and to other organs of the body, muscles, blood vessels, and glands. The peripheral nerves include the 12 cranial nerves, the spinal nerves and roots, and the autonomic nerves. The autonomic nerves are concerned with automatic functions of the body, specifically with the regulation of the heart muscle, the tiny muscles that line the walls of blood vessels, and glands.
Somatic Nervous System- the part of the peripheral nervous system associated with skeletal muscle voluntary control of body movements. The Somatic Nervous System consists of afferent nerves or sensory nerves, and efferent nerves or motor nerves.
Autonomic Nervous System- the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.
Parasympathetic- relating to the part of the automatic nervous system that counterbalances the action of the sympathetic nerves. It consists of nerves arising from the brain and the lower end of the spinal cord and supplying the internal organs, blood vessels, and glands.
Sympathetic- A division of the autonomic nervous system that is chiefly involved in producing an immediate and effective response during stress or emergency situations.
Sensory Neuron- a nerve cell that conducts impulses from a sense organ to the central nervous system.
Interneuron- a neuron that transmits impulses between other neurons, especially as part of a reflex arc.
Motor Neuron- a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.
Neuromuscular Junction- a synapse between a motor neuron and skeletal muscle. This lesson describes the events of synaptic transmission leading to contraction of skeletal muscle.
Acetylcholine- a compound that occurs throughout the nervous system, in which it functions as a neurotransmitter.
Norepinephrine- a hormone that is released by the adrenal medulla and by the sympathetic nerves and functions as a neurotransmitter. It is also used as a drug to raise blood pressure.
Epinephrine- a hormone secreted by the adrenal glands, especially in conditions of stress, increasing rates of blood circulation, breathing, and carbohydrate metabolism and preparing muscles for exertion.
Synapse- a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
White Matter- the paler tissue of the brain and spinal cord, consisting mainly of nerve fibers with their myelin sheaths.
Gray Matter- the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites.
Cerebral Cortex- the outer layer of the cerebrum, composed of folded gray matter and playing an important role in consciousness.
Lobes of the Brain- the different sections that the brain is divided into. Each lobe has a different function and is responsible for different emotions.
Limbic System- a complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions and drives.