Page 364 - Atlas of Histology with Functional Correlations

SECTION 1 • Central Nervous System: Brain

and Spinal Cord

MAMMALIAN NERVOUS SYSTEM

CNS consists of the brain and spinal cord
PNS consists of cranial, spinal, and peripheral nerves
Afferent nerves conduct to and efferent nerves conduct from the CNS

PROTECTIVE LAYERS OF THE

CENTRAL NERVOUS SYSTEM

Surrounded by bones, connective tissue, and cerebrospinal fluid (CSF)

Dura mater is the tough outermost connective tissue layer around the CNS
Delicate arachnoid mater is located below the dura mater
Innermost pia mater adheres directly to the surface of the brain and spinal
cord
Between pia mater and arachnoid mater is subarachnoid space that is filled

with CSF

CEREBROSPINAL FLUID (CSF)

Clear, colorless fluid that cushions and protects the brain and spinal cord
Continually produced by choroid plexuses in brain ventricles, with most in
the lateral ventricles

CSF is important for homeostasis, brain metabolism, and optimal neuronal
environment
CSF is reabsorbed into venous blood (superior sagittal sinus) via the
arachnoid villi

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