A&P I Ch

Flashcard maker : Lily Taylor
The two types of cells of the nervous system are
neurons and neuroglia
Neuron cell processes responsible for transmitting impulses away from the cell body are called
axons
The space between neurons is a
synapse
The nervous system
detects changes in the internal or external environment, controls the movement of muscles, regulates secretion, integrates information from several sources and uses it to respond appropriately.
__ convert information into nerve impulses that are transmitted to the CNS.
sensory receptors
Sensory receptors
monitor light, monitor sound, are part of the PNS, detect changes in and outside the body.
_________ support the axon from within.
Neurofibrils
Every neuron has
a cell body
A neuron may have
one axon and many dendrites
What is unique to neurons?
chromatophilic substance
Synaptic knobs are at the ends of
axons
Myelin
comprises much of the cell membrane of Schwann cells.
A myelinated nerve fiber is ______, whereas an unmyelinated nerve fiber is ______.
white, and composing the white matter of the brain and spinal cord; gray, and composing the gray matter of the brain and spinal cord
Most of the neurons in the brain and spinal cord are
multipolar
What is a type of neuroglia?
Astrocyte, oligondendrocyte, ependymal cell, schwann cell.
Which cells produce myelin in the brain and spinal cord?
Oligodendrocytes
Which cell is only found in the PNS?
Schwann cell
Dendrites on unipolar neurons are part of
sensory neurons
A reason that the CNS and PNS differ in their ability to regenerate after injury is that
axons of the CNS lack neurilemmae
Clusters of neuron cell bodies are called
ganglia
Presynaptic neurons release neurotransmitters by
exocytosis
Transmitting a nerve impulse from one neuron to another involves a
nerve impulse stimulating a presynaptic axon to release a neurotransmitter into a synaptic cleft.
A stimulus great enough to change the membrane potential and propagate an action potential is said to have reached _________.
threshold
When a nerve fiber is polarized, the concentration of
Na+ is higher on the outside of the membrane and K+ is higher on the inside.
Saltatory conduction
is faster than conduction on an unmyelinated fiber.
Which of the following ions cross cell membranes most readily?
Potassium
If a resting potential becomes more negative, the membrane is
hyperpolarizing
What is the correct sequence of events that follows a threshold potential?
1. The membrane depolarizes.
2. Sodium channels open and sodium ions diffuse inward.
3. The membrane repolarizes.
4. Potassium channels open and potassium ions diffuse outward.
2,1,4,3
Each neuron in the CNS receives input from
thousands of axons
The neurotransmitter that controls skeletal muscle contraction is
acetylcholine
Drugs that increase the actions of norepinephrine and/or serotonin by keeping them in synapses longer are most likely used to treat
clinical depression
During an action potential, calcium ions cause
sodium channels to close
The types of neurons that are organized into neuronal pools are
interneurons
Convergence refers to
axons from neurons in different parts of the nervous system contacting the same neuron.
Diverging axons amplify an impulse by
contacting many neurons.
An immune response that triggers inflammation of the spinal cord and brain, leaving scars is
multiple sclerosis
Marjorie takes an anti-anxiety drug so that she can sleep better and remain calm enough to study effectively. She begins by taking 25 milligrams every evening, but within a month, this dose is no longer helping, so she takes two pills. After another month, this dosage is no longer effective. This is happening because
the number of receptors to which the drug binds on neurons has declined.
The neurotransmitter most likely produced when a person uses a drug that creates a sense of well-being is
dopamine
A nerve is a single neuron that transmits nerve impulses.
False
Neuroglia are specialized to react to environmental change, and neurons support neuroglia.
False
The brain and spinal cord comprise the central nervous system.
True
Sensory receptors are part of the CNS.
False
Axon branches are called collaterals.
True
Nodes of Ranvier lie between neurons.
False
The space between neurons is called the neuronal space.
False
During the absolute refractory period, a stimulus of high intensity may trigger a nerve impulse.
False
In convergence, two or more incoming fibers contact a single neuron, whereas in divergence, impulses leaving a neuron pass into several output fibers.
True
Muscles and glands that respond to nerve impulses are called _______.
effectors
A(n) ______ is the junction between neurons.
synapse
The difference in electrical charge between the inside and outside of a polarized neuron cell membrane is called the ______ ______.
resting potential
A series of similar stimuli that increases change in local membrane potential is called _______.
summation
The somatic nervous system controls voluntary activities.
True
has two processes (one axon, one dendrite)
Bipolar neuron
lie within the brain or spinal cord and form links between other neurons
Interneuron
carry impulses out of the CNS to effector cells
motor neuron
has many processes arising from their cell body (one axon, many dendrites)
multipolar neuron
carry impulses from peripheral body parts to the CNS
sensory neuron
Has a single process extending from its cell body
unipolar neuron
structural support, formation of scar tissue, transport substances between neurons and blood vessels
astrocytes
form layer through which substances diffuse between interstitial fluid of brain and spinal cord and cererbrospinal fluid
ependymal cells
phagocytosis
microglial cells
form myelin sheath in brain and spinal cord
Oligodendrocytes
support ganglia in the PNS
satellite cells
speed neurotransmission
Schwann cells
creates sense of well being
norepinephrine
memory/vasodilation
nitric oxide
promotes alertness
histamine
pain perception(excitatory)
substance P
sleepiness
serotonin
pain reduction
Enkephalins

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