Page 2005 - Saunders Comprehensive Review For NCLEX-RN

1. Secreted in the ventricles; circulates in the
subarachnoid space and through the ventricles to the
subarachnoid space of the meninges, where it is
reabsorbed
2. Acts as a protective cushion; aids in the exchange of
nutrients and wastes
3. Normal pressure is 50 to 175 mm H O.
2
4. Normal volume is 125 to 150 mL.
J. Ventricles
1. Four ventricles
2. The ventricles communicate between the
subarachnoid spaces and produce and circulate CSF.
K. Blood supply
1. Right and left internal carotid arteries
2. Right and left vertebral arteries
3. These arteries supply the brain via an anastomosis at
the base of the brain called the circle of Willis.
L. Neurotransmitters
1. Acetylcholine
2. Norepinephrine
3. Dopamine
4. Serotonin
5. Amino acids
6. Polypeptides
M. Neurons
1. The neuron consists of the cell body, axon, and
dendrites.
2. The cell body contains the nucleus.
3. Neurons carrying impulses from the peripheral
nervous system to the central nervous system (CNS)
are called sensory neurons.
4. Neurons carrying impulses away from the CNS are
called motor neurons.
5. Synapse is the chemical transmission of impulses from
1 neuron to another.
N. Axons and dendrites
1. The axon conducts impulses from the cell body.
2. The dendrites receive stimuli from the body and
transmit them to the axon.
3. The neurons are protected and insulated by Schwann
cells.
4. The Schwann cell sheath is called the neurolemma.
5. Neurons do not reproduce after the neonatal period.
6. If an axon or dendrite is damaged, it will die and be
replaced slowly only if the neurolemma is intact and
the cell body has not died.
O. Spinal nerves
1. There are 31 pairs of spinal nerves.

2005