The Nervous System
sodium potassium pumps
restore the distribution of ions inside and outside a neuron's membrane following an action potential.
During repolarization
sodium channels close and potassium rushes out of the cell to temporarily re-establish the membrane potential.
what is first to occur during an action potential
sodium channels open
With each cycle of the sodium-potassium pump
the net effect is removal of one osmotic particle and one positive charge from inside the cell
Electrical impulses are transmitted between components of the central nervous system via
interneurons
a neuron has a resting potential of about __ millivolts
-70
which occurs last in association with the transmission of an impulse across a synapse
chemically gated channels for sodium open
what causes the release of neurotransmitter molecules?
an action potential reaching the end of the axon
Motor neurons transmit impulses __ from the central nervous system
away
An action potential moves along an
axon
a nerve impulse moves away from a neuron's cell body along
axons
the left and right sides of the cerebrum are interconnected by
corpus callosum
12 pair of __ nerves carry nerve impulses from the brain to glands, muscles, head, neck, and to abdominal and thoracic cavities.
cranial
a nerve impulse moves toward a neuron's cell body along
dendrites
Shifting the membrane potential of a neuron from negative to positive, due to inward movement of sodium ions, is referred to as ________.
depolarization
order of central nervous system meninges
dura mater, arachnoid, pia mater
the central nervous system is enclosed by membranes or meninges called
dura mater, pia mater, arachnoid
3 main anatomical an functional divisions of the brain are
forebrain, midbrain, hindbrain
in myelinated neurons the impulse jumps from
node of ranvier to node of ranvier
cells that provide direct protection and physical support to neurons are
neuroglial cells
oligodendrocytes and Schwann cells are both
neuroglial cells
a molecule that carries information across the synaptic cleft is a
neurotransmitter
Insufficient production of acetylcholine in the synapses of the brain, abnormal tangled neurons, and large deposits of beta amyloid are problems associated with
Alzheimer's disease
During a synaptic transmission what is released?
neurotransmitters
what type of cell makes up the myelin sheath of a motor neuron?
Schwann cells
a neurons nucleus is located in its
cell body
neurotransmitter that functions as an inhibitory agent, suppresses the sensation of pain
endorphins
axons insulated by a __ are able to conduct impulses faster than those not insulated
myelin sheath
cells in nerve tissue that support and protect neurons are __ cells
neurogial
During which of the following phases of an action potential do the sodium channels close and potassium channels open, releasing potassium from the neuron?
repolarization
excitatory neurotransmitters encourage the generation of new electrical impulses by
stimulating depolarization of postsynaptic neurons
the space between two neurons that meet at a synapse
synaptic cleft
What part of neuron relays signals from one neuron to another neuron to an effector
synaptic terminal
Neurons store neurotransmitter molecules in vesicles located within
synaptic terminals
The central nervous system is composed of
the brain and spinal cord
During an action potential
the inside of the neuron becomes positively charged relative to the outside
Saltatory conduction is
the process of conduction leaping along myelinated neurons
when a neuron is at resting potential
there are more potassium ions inside the neuron than outside
Sensory neurons transmit impulses __ the central nervous system
toward