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Dr. Ali Mohsin
(M.Sc., Ph.D. Anatomy, Histology & Embryology)
Neuroanatomy-1: Introduction(figures)
Neuroanatomy: Introduction
Dr. Ali Mohsin
Human brain
Hu
man
nervo
us system
Hu
man
brain
, spin
al cord
, &
spin
al nerve ro
ots
Human nervous system
Nervous System
Central (CNS) Peripheral (PNS)
Cranial NervesSpinal Cord
Spinal Nerves
Brain
Nervous System
Forebrain Midbrain
Cerebrum Diencephalon
Hindbrain
Pons CerebellumMedulla Oblongata
Brainstem
Autonomic Nervous System (ANS)
Somatic Nervous System (SNS)
Sympathetic Nervous System
Parasympathetic Nervous System
Enteric Nervous System
Motor Pathway Sensory Pathway
Anatomic classification
Functional classification
Nervous System Classifications
Neu
ral tub
e
Spin
al Co
rdB
rain
CN
S develo
pm
ent
Forebrain
Midbrain
Hindbrain
CNS development
CNS development
Motor & sensory columns in the brainstem
Neurons: parts, morphological & functional classifications
• Glial cells: supportive cells to the neurons.
Nervous tissue. N: neuron, G: glial cells, Np:neuropil (dendrites & axons
Nervous System Function
Grey matter• The grayish zone of the CNS. It consists of a huge number of
neuronal bodies (perikarya) & dendrites, glial cells, & the initial unmyelinated segments of axons.
• It occupies the outer zone (cortex) of the cerebrum & cerebellum, & the inner zone of the rest of the CNS.
• The thickness of the cortex varies from 1.5 to 4.5 mm. being thickest over the crest of a gyrus and thinnest in the depth of a sulcus.
• Exists also as deeper nuclei.
White matter• Whitish part of the CNS. It consists of aggregation of (myelinated)
nerve fibers (axons) & glial cells. No perikarya (cell bodies).
• It occupies the interior of the cerebrum & cerebellum, & the exterior of the rest of the CNS.
• White matter fibers:
o Association fibers (blue arrow)
o Commissural fibers (green arrow)
o Projection fibers (red arrow)
Association FibersCommissural FibersProjection Fibers
•N
erve: an aggregatio
n o
f nerve fib
ers (axon
s) in th
e PN
S
•G
anglio
n: an
aggregation
of n
erve cell bo
dies (p
erikarya) in th
e PN
S
•Tract (fascicu
lus): an
aggregation
of n
erve fibers in
the C
NS, h
aving th
e sam
e origin
& term
inatio
n, &
serving th
e same fu
nctio
n.
•Fu
nicu
lus (co
lum
n): a large b
un
dle o
f wh
ite matter w
hich
may co
nsist
of several fu
nctio
nally d
ifferent tracts o
r fasciculi.
•R
eticular fo
rmatio
n: a regio
n in
the b
rain stem
& u
pp
er spin
al cord
co
nsistin
g of a gro
up
of in
tercon
nected
neu
ron
s intersp
ersed am
on
g n
erve fibers.