largest, most numerous glial cells; maintain blood-brain barrier to isolate CNS from general circulation; provide structural support for CNS; regulate ion and nutrient concentrations; perform repairs to stabilize tissue and prevent further injury
Supporting cells of the peripheral nervous system responsible for the formation of myelin.
Type of glial cell, line the exterior surface of neurons in the peripheral nervous system. Satellite cells also surround neuron cell bodies within ganglia. They supply nutrients to the surrounding neurons and also have some structural function.
rough endoplasmic recticulum in neurons; important for protein production, i.e. NA/K protein channels
Input Zone (Dendrites, Cell Body)
The part of a neuron that receives information, from other neurons or from specialized sensory structures. Usually corresponds to the cell's dendrites.
Trigger Zone (Initial Segment of Axon)
nerve impulses arise most often at the junction of the axon hillock and initial segment
Output Zone (Axon Terminals)
swellings at the ends of the axon known as axon terminals that communicate the cell's acitivity to other cells
specialized region of the axon, which connects the inital segment of the axon to the cell body
bulb like structers at end of axon contain neuro transmitters that carry neuron message into synapse
Synaptic End Bulbs
found at end of axon terminal & contain synaptic vesicles that are filled with neurotransmitters
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.
tiny oval-shaped sacs in a terminal of one neuron; assist in transferring mineral impulse from one neuron to another neuron by releasing specific neurotransmitters
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
cell communicaton via chemical signals-receptors specificity/ receptor activation produces a second messengr(chemical) inside of cell
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
a fatty substance that helps insulate neurons and speeds the transmission of nerve impulses
Nodes of Ranvier
small gaps of exposed axon, between the segments of myelin sheath, where action potentials are transmitted
neuron with just one process extending from the cell body; are always sensory nerons
A neuron with a single axon and a single dendrite, often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon may innervate many different muscles, or other things.
Sensory Neurons (Afferent)
neurons that carry incoming information from the sensory receptors to the brain and spinal cord
Motor Neurons (efferent)
neurons that carry outgoing information from the central nervous system to the muscles and glands
Association Neurons (Interneurons)
Also called interneurons, located only in the brain or spinal cord, these neurons contact sensory neurons to motor neurons; the switch board of the nervous system.
outermost layer of connective tissue on the spinal nerve; a dense network of collagen fibers
contains the axons of the sensory neurons in the dorsal root ganglion; each segment of the spinal cord is associated with a pair of these
contains axons of somatic motor neurons and sometimes visceral motor neurons that control peripheral effectors; each segment of the spinal cord is associated with a pair of these
nerves composed of both sensory and motor fibers, nerves that contain both sensory and motor fibers and have the ability to send and receive messages
Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons.