nervous system Flashcards
afferent
sensory
efferent
motor
integrative
interneurons
autonomic
involuntary
somatic
voluntary
“fight or flight”
sympathetic
“rest and digest”
parasympathetic
visceral
involving organs
the central vervous system consists of what
brain and spinal cord
the peripheral nervous system consists of what
nerves and ganglia
What are the two major divisions of the PNS?
sensory (afferent) and motor (efferent)
What are the two major divisions of the motor nervous system?
somatic (voluntary) and autonomic (involuntary)
What are the two divisions of the autonomic nervous system?
sympathetic (fight or flight) and parasympathetic (rest and digest)
What is the big difference between neurons and neuroglia?
neurons send and receive electrical messages (excitable)
neuroglia support and protect neurons but don’t send or receive electrical messages
make myelin in the CNS
oligodendrocytes
make myelin in the PNS
Schwann cells/neurolemmocytes
produce and circulate cerebrospinal fluid
ependymal cells
clean up dead and damaged cells in the CNS
microglia
most abundant and versatile glial cell, forms blood-brain barrier
astrocytes
surround nerve cell bodies in the PNS
satellite cells
short, numerous, receptive processes of neurons
dendrites
long, conductive process, carries impulse away from the neuron cell body
axon
biosynthetic center of a neuron
cell body/soma
chromatophilic substance, rough ER in a nerve cell body
Nissl bodies
bundles of fibers inside a nerve that help with structure and stability
neurofibrils
“aging pigment” that is a lysosomal product
lipofuscin
cone-shaped first part of an axon where the impulse is initiated
axon hillock
branches of the axon
axon collaterals
secretive ends of a neuron
axon terminals
enlarged ends of axon terminals
synaptic bulbs
store neurotransmitter inside synaptic bulb
synaptic vesicle
when things are transported from the cell body toward the axon terminals
anterograde
when things are transported from the axon terminals toward the cell body
retrograde
fatty covering over an axon that allows messages to travel faster
myelin
myelin sheath gaps
nodes of Ranvier
the lighter regions of the brain and spinal cord covered in myelin
white matter
the darker regions of the brain and spinal cord not covered in myelin
gray matter
clumps of cell bodies in the CNS
nuclei
clumps of cell bodies in the PNS
ganglia
bundles of axons in the CNS
tracts
bundles of axons outside the CNS
PNS
the exposed portion of a Schwann cell membrane
neurolemma
Give 2 reasons retrograde transport is significant.
allows some viruses to move to the cell body and used as a tool for introducing viruses to treat genetic disorders
Which structural neuron type is most common?
multipolar
Which structural neuron type is least common?
bipolar
What happens to opposite charges?
attract
What is needed to keep opposite charges apart?
energy
the difference in charge across a membrane
potential difference
What happens when opposite charges are allowed to come together?
energy is released
the unit used to measure the difference in charge between two points
volts
a tool to measure the difference in charge between two points
voltmeter
the flow of electrical charge from one point to another
current
the hindrance to current flow
resistance
the relationship between current, voltage, and resistance is shown by this
Ohm’s Law
substances with high electrical resistance
insulators
substances with low electrical resistance
conductors
What provides resistance to current in neurons?
plasma (cell) membrane
the chemicals which serve as ion channels
proteins
channels that are always open
leakage (nongated)
channels that open when a specific neurotransmitter binds to it
chemically (ligand) gated
channels that open and close in response to changes in the membrane potential
voltage-gated
channels that open when receptors are physically deformed
mechanically gated
how ions move passively from high to low concentration and toward opposite charges
electrochemical gradient
the difference in charge on either side of a resting neuron membrane
resting potential
having opposite charged ends or sides
polarized
a loss of charge difference
depolarization
an increase in membrane resting potential, the inside becomes more negative
hyperpolarization
a local change in membrane potential, magnitude varies with signal strength
graded potential
the minimum stimulus needed to cause a response
threshold
a weak stimulus that doesn’t cause a response
subthreshold
when the message is sent along the axon
propagated
the nerve either sends the message or doesn’t, nothing in between
all-or-none phenomenon
the time when a neuron can not respond
absolute refractory period
the time when the threshold stimulus is greatly elevated
relative refractory period
How are the gates arranged when the neuron is resting?
all closed
What gates open to depolarize the membrane and send the action potential
Na+
What gates open to repolarize the membrane?
K+
a nerve impulse, long-distance signal
action potential
What is the purpose of graded potentials?
cause action potentials
What 2 factors affect the speed of a nerve impulse?
diameter of fiber and amount of myelin
slow impulse conduction in unmyelinated fiber
continuous
fast impulse conduction in myelinated fibers
saltatory
an autoimmune disease characterized by hardened lesions on the myelin sheaths
multiple sclerosis
large diameter fibers with thick myelin, fastest
Group A
small, unmyelinated fibers, slowest
Group C
medium thick fibers with light myelin
Group B
quick successive stimuli summate to increase the amplitude of a graded potential
temporal summation
multiple stimuli at different locations increases the amplitude of a graded potential
spatial summation
immature nerve cells
neuroblasts
What happens to most neuroblasts
die if don’t make good connections
Why are most tumors of the nervous system gliomas?
neurons are so specialized that they have lost the ability to divide
What three things disrupt nerve messages?
local anesthetics block Na channels
cold and pressure disrupt blood flow
What ions are responsible for the resting potential or charge difference in a resting neuron?
Na+ and K+
