Introduction to Neuroanatomy
Done by
Dr. Rafid Remthan AL-Temimi
Clinical Radiology CABM ,DMRD,MBCHB,
المرحلة
:
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المادة
:
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امعة ذي قار
كلية الطب
Part 2
– Made of all nerves outside the brain and spinal cord
(PNS) is made up of peripheral nerves that connect the CNS to the rest of the body. These neurons
can
regenerate if damaged.
12 pairs of cranial nerves
31 pairs of spinal nerves
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Dr. Rafid Remthan AL-Temimi ; Clinical Radiology ( CABM) 2020
•
PNS can be subdivided into 2 divisions:
(1) Autonomic
•
Cranial & spinal nerves connecting CNS to
heart, stomach, intestines, glands
•
Controls unconscious activities
(2) Somatic
•
Cranial & spinal nerves connecting CNS to skin
& skeletal muscles
•
Oversees conscious activities
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A. Cranial Nerves:
12 pairs & their branches
Some responsible for special
senses: sight, hearing, taste, smell
Others receive sensations: touch,
pressure, pain, temperature
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Cerebrum
from the telencephalon and diencephalon respectively :
1.
olfactory nerve (CN I) ; Sense of smell
2.
optic nerve (CN II); Sense of vision
Midbrain
1.
oculomotor nerve (CN III) ; Eye movement
2.
trochlear nerve (CN IV) ; Eye movement
Pons:
1.
trigeminal nerve (CN V) Eye,
jaws sensation/movement
2.
abducens nerve (CN VI); Eye movement
3.
facial nerve (CN VII); Face, scalp, tongue sensation/movement
4.
vestibulocochlear nerve (CN VIII) ; Hearing, balance
Medulla oblongata:
1.
glossopharyngeal nerve (CN IX) ; Taste, swallowing
2.
vagus nerve (CN X) ; Autonomic control of viscera
3.
accessory nerve (CN XI) ; Swallowing, pectoral girdle movement
4.
hypoglossal nerve (CN XII) ; Tongue movement
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
B. Spinal Nerves:
31 pairs & their branches
carries messages to & from the spinal
cord
Both sensory and motor nerves
• 31 spinal nerves:
– 8 cervical.
– 12 thoracic.
– 5 lumbar.
– 5 sacral.
– 1 coccygeal.
Dr. Rafid Remthan AL-Temimi ; Clinical Radiology ( CABM) 2020
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University Of Thi-Qar
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Autonomic Nervous System
Helps maintain a balance in involuntary
functions of the body. But allows the body to
react in times of emergency.
Dr. Rafid Remthan AL-Temimi ; Clinical Radiology ( CABM) 2020
Two divisions of ANS:
1. Sympathetic nervous system:
acts
in emergency.
2. Parasympathetic nervous system:
counter acts the sympathetic ns
after the emergency
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Neuronal and Non-neuronal Cells
of the Nervous System
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Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Definition and Parts of Neurons:
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● Neuron is the main functional unit of the nervous system.
● Neurons are composed of:
○ Cell body.
○ Dendrites.
○ Axons
University Of Thi-Qar
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Definition and Parts of Neurons:
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● Collection
of cell
bodies
constitute
grey
matter,
while collection of
axons constitute white matter.
● Cell bodies are concentrated mainly in:
○ Cerebral and cerebellar cortex.
○ Spinal cord grey matter.
○ Various nuclei in the CNS.
○ Various ganglia in the PNS
University Of Thi-Qar
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Definition and Parts of Neurons:
White Matter contains 3 types of nerve fibers:
Commissural fibers:
connect the same cortical
areas of the two cerebral hemispheres.
■ Corpus callosum.
■ Anterior and posterior commissures.
Association fibers:
connect cortical areas in the
same cerebral hemisphere.
Projection fibers:
connect the cerebral cortex with
the subcortical areas.
● White matter is present mainly in various sensory and motor tracts
in the CNS and fibers.
● Spinal and cranial nerves of the PNS.
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Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Commissural fibers:
■ Corpus callosum.
■ Anterior and posterior commissures.
Types of Neurons:
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Morphological classification of neurons:
● Multipolar neurons.
● Bipolar neurons.
● Unipolar (or pseudounipolar) neurons.
● Anaxonic neurons.
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Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
University Of Thi-Qar
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Non-neuronal Cells:
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● They are called neuroglia or glial cells.
● They have various roles support and functions to
neurons.
● Major types of glial cells:
○ Astrocytes.
○ Oligodendrocytes.
○ Microglia.
○ Ependymal cells.
○ Schwann cells.
○ Satellite cells of ganglia.
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Non-neuronal Cells:
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● Astrocytes have the following main functions:
○ regulate the extracellular ionic
concentration.
○ support the neurons physically.
○ contribute to the blood-brain barrier.
University Of Thi-Qar
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Anatomy lecture . 2
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Non-neuronal Cells:
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● Oligodendrocytes are found in the CNS white matter, they
produce the myelin sheath.
● Microglia are the main immune defence in the CNS, they
originate from monocytes.
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Microglia
Non-neuronal Cells:
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● Ependymal cells line the brain ventricles and the spinal canal, they assist in
the movement of CSF.
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
● Schwann cells produce myelin sheath in the PNS.
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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● Satellite cells of ganglia support the neuronal cell bodies in the
ganglia.
University Of Thi-Qar
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Anatomy lecture . 2
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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University Of Thi-Qar
College Of medicine
Anatomy lecture . 2
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stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
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University Of Thi-Qar
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Anatomy lecture . 2
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stage
Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
The human nervous system is a complex communications network,
consisting of two integrated systems:
muscle
peripheral nerve
spinal cord
brain
Reflex arcs
A simple way to examine the function of the nervous system,
when investigating whether a person has a neurological disease,
is by testing for spinal reflex arcs. These are automatic responses
needing no input from the brain and no thought. One familiar
reflex is the rapid response to touching something very hot:
1
Sensory nerves in the skin detect potential
danger.
sensory
2
A nerve impulse travels from the skin to the
spinal cord, where it transfers from sensory
to motor nerves.
motor
3
Motor nerves carry impulses to muscles that
withdraw the hand from the heat.
Reflex arcs
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University Of Thi-Qar
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020
Thank you……….
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University Of Thi-Qar
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Anatomy lecture . 2
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Dr.Rafid Al-Temimi
Dr.Rafid Remthan AL-Temimi,Clinical Radiology,CAMB, 2020