8.3 Cells Of The Nervous System Flashcards
2 types of cells that make up the nervous system
Neurons
Neuroglia
also called nerve cells receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs
Neurons
3 parts to a neuron
cell body
2 types of processes: dendrites and axon
contains a single nucleus
cell body
source of information for gene expression
nucleus of the neuron
surround the nucleus
Extensive rough ER, Golig apparatus, mitochondria
organize cytoplasm into ditsinct areas
Large number of neurofilaments (intermediate filaments) and microtubules
Short, often highly branching cytoplasmic extensions that are tapered from their bases at the neuron cell body to their tips
Dendrites
usually receive information from other neurons or from sensory receptors and transmit the information toward the neuron cell body
Dendrites
A single long cell process extending from the neuron cell body
Axon
Area where the axon leaves the neuron cell body
Axon hollock
conduct action potentials away from the CNS
Axons of sensory neurons
conduct action potentials away from the CNS
Axons of motor neurons
An axon may remain unbranched or may branch to form ____
collateral axons
highly specialized insulating layer of cells surrounding some axons
Myelin sheath
have many dendrites and a single axon
Multipolar neurons
have two processes: one dendrite and one axon
Bipolar neurons
Type of neurons within the CNS and nearly all motor neurons
Multipolar neurons
Type of neuron loacted in some sensory organs, such as in the retina of the eye and in the nasal cavity.
Bipolar neurons
Have single process extending from the cell body which divides into two processes a short distance from the cell body. One extends to the periphery, the other to the CNS
Pseudo-unipolar neurons
Type of neuron in most sensory neurons
Pseudo-unipolar neurons
are the nonneuronal cells of the CNS and the PNS
Neuroglia or glial cells
Most ____ retain the ability to divide whereas neurons do not
neuroglia
serve as majot supporting cells in the CNS
Astrocytes
can stimulate or inhibit the signaling activity of nearby neurons
Astrocytes
participate with the blood vessel endothelium to form the blood-brain barrier
Astrocytes
A permeability barrier between the blood and the CNS
Blood-brain barrier
help limit damage to neural tissue
Astrocytes
line the fluid-fliled cavities within the CNS
Ependymal cells
produce CNS
Ependymal cells
help move CSF through the CNS
Ependymal cells
act as immune cells of the CNS
Microglia
help protect the brain by removing bacteria and cell debris
Microglia
provide insulating material that surround the axon in the CNS
Oligodendrocytes
provide insulating material that surround the axon in the PNS
Schwann cells
rest in indentations of the oligodendrocytes in the CNS and Schwann cells in the PNS
Unmyelinated axons
an excellent insulator that prevents almost all ion movement across the cell membrance
Myelin
gaps in the myelin sheath that occur about every millimeter between the oligodendrocyte segments or between individual Schwann cells
nodes of Ranvier
can occur at the nodes of Ranvier
Ion movement
Increases the speed and efficiency of action potential
Myelination of an axon
Consists of groups of neuron cell bodies and their dendrites, where there is very little myelin
Gray matter
gray matter on the surface of the brain
cortex
clusters of gray matter located deeper within the brain
nuclei
a cluster of neuron cell bodies
ganglion
consists of bundles of parallel axons with their myelin sheaths, which are whitish in color
White matter
also called conduction pathways, which propagate action potentials from one area of the CNS to another
nerve tracts
bundles of axons and their connective tissue sheaths
nerves
