Histology of Nervous System Flashcards
Master integrating and coordinating system, continuously monitoring and processing sensory info from external environment and from w/i body
Nervous System
Two primary divisions that make up the nervous system
central nervous system (CNS)
Peripheral nervous system (PNS)
What does the CNS consist of
brain and spinal cord
what does the PNS consist of
all the nervous elements located outside the CNS
System that includes nerves, sensory receptors, some clusters of neuron cell bodys
PNS
Nervous tissue is made up of 2 principal cell types
neurons and neuroglia
Serve the need of the delicate neurons by supporting and protecting them
neuroglia
Another name for neuroglia
glial cells
what does neuroglia cells of the CNS include
astrocytes, oligodendrocytes, microglial cels, ependymal cells
what does the neuroglia cells in PNS include
Schwann cells and satellite cells
what are Schwann cells called
neurolemmocytes
Neuroglia that act as phagocytes
microglial cells
myelinate the cytoplasmic extensions of the neurons
oligodendrocytes and schwann cells
controll the chemical environment around neurons
astocytes
T or F. Neuroglia are capable of generating and transmitting nerve impulses
F
Another name for nerve cells
neurons
basic functional units of nervous tissue
neruons
most abundant CNS neuroglia
astrocytes
defensive cells in the CNS
microglial cells
Line cerebrospinal fluid-filled cavaties
ependymal cells
processes that form myelin sheaths around CNS axons
oligodendrocytes
Another name for neuron cell body
soma
Biosynthetic center and receptive region
cell body
Makes up the gray matter of the CNS
cell body
Clusters of neurons cell bodies in the PNS
ganglia
Two prominent structures found in the cytoplasm
neurofibrils and chromatophilic sumstance
provide support for the cell and a means to transport substances through the neuron
neurofibrils
clusters of rough ER and ribosomes involed in metabolic activities of the cell
chromatophilic substance
Neurons have 2 types of processes. What are they?
dendrites, axons
receptive regions that bear receptors for neurotransmitters released by axon terminals of other neurons
dendrites
Also called nerve fibers
axons
form the impulse generating and conducting region of the neuron
axons
White matter of CNS made up of what
axons
the initial region of the axon arises from a cone shaped area of the cell body
axon hillock
any long axon
nerve fiber
the axon ends in many small structures
axon terminals
Each axon terminal of the neuron is separated from the cell body or dendrites of the next neuron by a tiny gap called
synaptic cleft
Structural Classification – grouped according to the number of processes extending from the cell body (multipolar, bipolar, unipolar)
Neurons
three or more processes. Major neuron CNS.
multipolar neurons
two processes, axon and dendrite, extending from opposite sides of the cell body. Some special sense organs acting as receptor cells.
Ex. retina of the eye and in olfactory mucosa
bipolar neurons
ingle short process emerging from the cell body and dividing T-like into proximal and distal branches.
Found chiefly in ganglia in the PNS functioning as sensory neurons.
unipolar neurons
grouped according to the direction in which the nerve impulse travels relative to the CNS.
functional classification of neurons
transmit impulses from sensory receptors in the skin or internal organs toward or into the CNS
Sensory or afferent neurons
Except for bipolar neurons, virtually all sensory neurons are
unipolar
carry impulses away from the CNS to the effector organs (muscles and glands).
Motor or efferent neurons
are multipolar, and their cell bodies are located in the CNS
Motor neurons
between motor and sensory neurons pathways and shuttle signals. Multipolar
Interneurons or association neurons
In the CNS, bundles of axons are called
tracts
In the PNS, bundles of axons are called
nerves
Conduct impulses only toward the CNS
sensory (afferent) nerves
Carry impulses only away from he CNS
motor (efferent) nerves
nerves carrying both sensory (afferent) and motor (efferent) are called
mixed nerves
Neuron conducting impulses toward the synapse is the
presynaptic neuron
Neuron transmitting the electrical signal away from the synapse is
postsynaptic neuron
Presynaptic neuron or the postsynaptic neuron is the information sender
presynaptic neuron
Presynaptic neuron or the the postsynaptic neuron is the information receiver.
postsynaptic neuron
T or F. Most neurons function both as presynaptic and postsynaptic neurons.
T
