The three protective membranes that surround the brain and the spinal cord.
Protects brain and spinal cord from surrounding bone and Fills space in brain and spinal cord.
Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons.
A column of nerve tissue running through the vertevral column. A major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain noun.
Ex. a long tube-like structure extending from the base of the brain through the vertebral canal to the upper lumbar region.
A strand of axons through which impulses travel.
A neuron that detects a stimulus.
A neuron that carries impulses from the spinal cord to muscle cells.
Neurons that connect with other neurons.
A division of the peripheral nervous system that acquires info from the external and internal environments of the body.
A division of the peripheral nervous system that allows the body to react to the brain's interpretation of sensory information.
Somatic Nervous System
The division of the peripheral nervous system that controls skeletal muscles.
Occurring automatically and involuntarily as a result of the nervous system's reaction to a stimulus.
A reflex extension of the leg resulting from a sharp tap on the patellar tendon.
A muscilar reaction to a stimulus that is initiated by the neurons of the spinal cord instead of the brain.
Autonomic Nervous System
A division of the peripheral nervous system that contols the involuntary actions that regulate the body's internal environments.
The part of the autonomic nervous system that controls internal organs during conditions of high stress or increased activity.
The part of the autonomic nervous system that monitors the routine operations of the internal organs and returns the body to calmer functioning after arousal by the sympathetic division.
Branching extensions of neuron that receives messages from neighboring neurons.
The endpoint of a neuron where neurotransmitters are stored.
A layer of myelin encasing (and insulating) the axons of medullated nerve fibers.
Supporting cells of the peripheral nervous system responsible for the formation of myelin.
Nodes of Ranvier
Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node, thus increasing the speed of conduction (saltatory conduction).
Synaptic gap or synaptic space; tiny gap between the terminal of one neuron and the dendrites of another neuron (almost never touch); location of the transfer of an impulse from one neuron to the next.
Chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
When a neuron is in polarization; more negative ions are inside the neuron cell membrane with a positive ions on the outside, causing a small electrical charge; release of this charge generates a neuron's impulse (signal/message).
A neural impulse; a brief electrical charge that travels down an axon. the action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane.
(neurology) The time after a neuron fires or a muscle fiber contracts during which a stimulus will not evoke a response.