Nervous Tissue Flashcards
consists of the brain and spinal cord
central nervous system (CNS)
consisting of the nerves extending toward or away from CNS and ganglia (aggregates of nerve cell bodies outside CNS)
peripheral nervous system (PNS)
the two major types of nervous cells
glial cells and neurons
responsible for condition, propagation and reception of nervous impulses. processes called axons or dendrites extend from these cells
neurons
(neuroglia) cells associated with neurons. no axons or dendrites. these cells are involved in nutrition, support, insulation and protection of neurons
glial cells
nervous tissue where neuron perkikarya (cell bodies), glial cells, axons, dendrites, synapses are found
gray matter
nervous tissue where axons, myelin sheaths, oligodendrocytes, and global cells are found. no neuron perikarya, no synapses
white matter
nerve cell body, contains nucleus and typical cell organelles
perikaryon
nerves have lots of this for synthesis of structural and transport proteins, Nissel bodies seen with light microscope
rough ER
pigments deposit vesicles, increase with age, from autophagosome activity
lipofuscin deposit.
inclusions
cell processes, may be branched, forms receptive area for synaptic contacts from other neurons. neurons have more than one of these
dendrite
single, long, thin cell process extending away form the perikaryon. may be branched, the ends of branches form synapses with other neurons or muscle cells, may be myelinated or not
each neuron only has one of these
axon
oligodendroglia myelinate in
CNS
Schwann cells myelinate in
PNS
pyramid shaped region where axon originates from perikaryon
axon hillock
unmyelinated initial portion of axon
initial segment
axons carry _______ to synapses at end of axon
electrical impulses (action potentials)
specialized junctions with other cells that are along the length or at the end of an axon.
- act as transmission points for electoral impulses or chemical (ionic changes)
synapses
synapses at end of an axon or axon branches that are swollen into a club shape are called
boutons terminaux
synapses along the length of an axon result in ________ (swellings) in the axon called
varicosities
boutons en passage
part of the neuron plasmalemma
terminal or presynaptic membrane
this is a space between the presynaptic membrane of the axon and the plasmalemma of the cell that receives the synaptic input
synaptic gap or cleft
part of the plasmalemma of a cell that receives input
postsynaptic membrane
many small vesicles in the bouton that contain neurotransmitters
synaptic vesicles
name two neurotransmitters
acetylcholine and serotonin
type of neuron where there are more than 2 processes ( one axon + multiple dendrites) most of neurons on brain and spinal cord
multipolar neuron
multipolar neurons are found mainly
in the brain and spinal cord
the brain and spinal cord consist of what type of neuron
multipolar neuron
type of neuron where there are 2 major processes ( axon and dendrite ) but may be branched at ends, sensory neurons in retina, cochlea, and olfactory epithelium have this type
bipolar neuron
type of neuron where there are two major processes that are fused oblong portions closest to perikaryon, found in spinal ganglia and in some cranial ganglia
pseudounipolar
pseudo unipolar developmentally starts out as
bipolar
efferent, action potential moves from CNS to effector organ (e.g. muscle) in peripheral regions
motor neurons
afferent, action potential moves from sensory organ to CNS (e.g. neuron processes (effectively dendrites, but often called axons) associated with pacinian corpuscles (touch and pressure)
sensory neurons
form connections between neurons
interneurons
there are many more ____ ____ in the nervous system than there are neurons
glial cells
4 glial cells found in CNS
- astrocyte
- oligodendrocyte
- microglia cell
- ependymal cell
provide both mechanical and metabolic support for neurons, regulating the environment where they function, they contribute to the blood brain barrier and control transport of substances from the blood to neural tissue, they also help coordinate nerve pathway development
astrocyte
glial from CNS
two types of astrocytes
protoplasmic astrocytes
fibrous astrocytes
granular cytoplasm, many branches on thicker and shorted processes. found in gray matter.
protoplasmic astrocytes
long slender processes, found in white matter mainly, function unknown, type of glial cell in CNS
fibrous astrocyte
forms part of the myelin sheath for a few axons in CNS
smaller than astrocyte
both gray and white matter
these cells must be futures with neurons in order to get neurons to grow in tissue culture - interactive association
oligodendrocyte
provide a protective function to nervous tissue in that that can become phagocytic
elongated cell body that stains densely, can be confused with oli.
glial cell in CNS
microglia cells
line the cavities in the CNS
form the lining of the ventricles of the brain and the central canal of the spinal cord, make a contribution to the production of cerebrospinal fluid (CNS)
dilated cells forming single layer of cubical epithelium that lines the entire neurocoel
ependymal cells
types of glial cells in the PNS
- Schwann cells
2. satellite cells
forms a part of the myelin sheath for an axon in PNS
Schwann cells
encapsulate and provide protein and support for the cell bodies of peripheral neurons in the many peripheral ganglia
satellite cell
nerves are surrounded by a thick connective tissue sheath composed of collagenous fibers and fibroblasts and containing small blood vessels that is called the _____. this extends into the nerve and between the fascicles.
epineurium
nerve fibers
each bundle (or fascicle) of axons is surrounded by a layer of connective tissue called the
perineurium
each axon within each bindle is individually surrounded by a layer of reticular connective tissue called the
endoneurium
myelin acts to ____ axon, it _____ ___ condition of electrical impulses due to the formation of nodes of rangier where adjacent sheath cells meet along the length of an axon
insulate axon
speeds up condition
the ___ the nodes of rangier along a given axon, the faster the transmission
fewer
involuntary component to the nervous system called
autonomic nervous system
autonomic nervous system important in three things
- control of smooth muscle
- secretion of some glands
- modulation of some glands
two parts of the autonomic nervous system
- sympathetic
2. parasympathetic
part of the autonomic nervous system
neurotransmitter is norepinephrine- adrenergic synapses.
generally stimulates
enhances activity
sympathetic
neurotransmitter of the sympathetic nervous system
norepinephrine
part of the autonomic nervous system
neurotransmitter is acetylcholine- cholinergic synapses
generally slows activity
parasympathetic
neurotransmitter of the parasympathetic nervous system
acetylcholine
an aggregation of neurons and associated glial cells outside the CNS
ganglion
purely sensory ganglia, part of voluntary nervous system, connective tissue capsule surrounds ganglia
- neurons cortical (peripheral)
- shoe Nissl bodies and lipofuscin
dorsal root ganglia, cranial ganglia