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Lecture 1 - Overview of Nervous System.doc
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Clinical NeuroscienceTopic1: Organization of Nervous System (Dr. Poblete)
Overview:A. Central Nervous System
1. Brain- Supratentorial structures
o Cerebrum- Infratentorial structures
o Cerebellumo Brainstem
Midbrain Pons Medulla
2. Spinal cord- Begins after the f. magnum and ends at L1 (conus
medullaris)- Covered by meninges- Has 31 spinal nerves
o 8 cervical (although there are only 7 cervical segments)
o 12 thoracico 5 lumbar (conus medullaris)
o 5 sacral (conus medullaris)
o 1 coccygeal
B. Peripheral Nervous System- Has 3 functions
o Motor o Sensoryo Parasympathetic
- Based on the cranial nerve (CN) …netter na lang
CN Notes1 Olfactory bulb/tract
olfactory nervesCerebrum level
2 Optic Found beneath cerebrum (supratentorial)
3 Extraocular muscles (Infratentorial)Located in midbrain
4 Trochlear - Only CN exiting from the back- Located in midbrain
5 Sensory and motor to face Pons6 Extraocular muscles7 Facial movement; taste
(tongue)8 Hearing9 Pharyngeal muscles Medulla
10 Pharyngeal muscles11 SCM12 Tongue
Lecture per se:
A. PNSCervical enlargementLumbar enlargement
Spinal Nerves
C5-T1 Roots contribute
Brachial plexus: - Nerve roots c5-T1 - To upper extremities - Sensory/motor/autonomic damage (Manifests in upper extremities)
L1-S2 Lumbosacral plexus
- L1-S2 roots - All belong to PNS - Conus medullaris at L1 (lumbar puncture done below L1)
Nerves can regenerateCNS can’t regenerate
B. ANSSomatic Nervous System = voluntary controlAutonomic Nervous System = Internal Organs/glands
Smooth, cardiac, glandsEndocrine, homeostatic organs
Originate from CNS, has peripheral componentsSympathetic Parasympathetic
From brainstem and sacral (called: craniosacral)
Thoracolumbar (paravertebral ganglia) = origin of sympathetic autonomic outflow
CN 3: pupilllary constrictionCN 7: salivationCN 9: salivation (parotid gland)CN 10: vagus (controls thoracic organs)
Lateral hornIntermediolateral cell column (IML) uses Ach neurotransmitter to send
sympathetic preganglionic signals to paravertebral gangliaPreganglionic: shortNeurotransmitter: Ach
Preganglionic: longNeurotransmitter: Ach
Postganglionic: longNeurotransmitter: norepinephrineExcept sympathetic to sweat glands which secrete Ach
Postganglionic: shortNeurotransmitter: Ach
BRAINSTEM:Medulla cell layersAnterior Middle PosteriorBasalis Tectum TegmentumMotor pathway thalamic nucleus
specific for hearing
Has nuclei of cranial nerves; substantia nigraperiaqueductal grey
From cerebrum send projections to superior colliculi, via inferior quadrigeminal brachiumrelay center for auditory pathway
Exit of CN4
crura cerebri inferior colliculi Ventral to cerebral aqueduct
Emphasis:1. Thalamus – above midbrain/hypothalamus
– Level of cerebrum, deviates of diencephalon – Encloses 3rd ventricle – Sensory pathways (afferent) on the way to Cerebral cortex w/o passing thalamus? – V-shaped: Int. Medullary Lamina – Ant.MedialLat. Nucleus (relay nucleus)
2. Fornix – above midbrain3. Corpus callosum – connects frontal L lobe to frontal R lobe
– Association fibers or commissural fibers4. Cingulate gyrus – part of limbic system w/c goes to (#5)5. Hypothalamus – supra… = origin of releasing hormone
Autonomic, endocrine fxn – Amygdala: limbic system
6. Pituitary – infra7. Optic chiasm
C. Neurons and GangliaNeurons have 2 types of cellsNeurons – generate electrical impulses
– Nerve cell body/soma/perikaryon– Dendrite (afferent)– Function: membrane is electrically active, forming Synapsesa.b.c.d.e. pyramidal cellsf. purkinje
neuroglia – astrocytes > oligodendrites > microglia (BBB) ( myelin) (phagocytic)
Blood brain barrier (BBB) – Astrocytes have “end feet” also known as “glial feet” which are attached to the basement membrane of capillaries (via TIGHT JUNCTIONS).
D. White vs. Gray MatterWhite Matter (axons, myelinated)
- association fibers: horizontal- commissural fibers: ventral- projection fibers: ascending/descending fibers
Gray Matter (mostly nerve cell bodies: soma, perkaryon)- nuclei (CNS)- ganglion (PNS)
E. CerebellumSurface: focal areas w/ focal functionsAssociation area: integrate sensory info and initiate motor movementsImportant: 2 hemispheres, 1 midline (vermis), and 1 floculonodular lobe
Cerebrovestibular pathway: cortex white nuclei
Nuclei (lateral to medial): Dentate, Emboliform, Globus, Fastigius
Impulses: cortex nuclei exits cerebellumBrainstem: Sup. Colliculi: cerebellum connected via peduncles
Inf. ColliculiSuperior peduncle oculomotor/trigeminal n. (pons/mdbrain)Middle peduncle hypoglossal n. (medulla)
foramen magnum –separates the lowermost portion of medulla from the spinal cord
Inferior peduncle
F. Basal Ganglia1. caudate2. lenticular nucleus and globus pallidus
internal capsule-between caudate3. subthalamic nucleus4. substancia nigra
G. Limbic systemHippocampus: belongs to limbicFornix attached to mamillary bodies
H. Spinal CordOuter white = posterior, lateral, anterior columnInner gray = IML = autonomic
Post. Gray horn = sensoryAnt. Gray horn = motor
Rexed Laminae1-6 dorsal gray horn7-9 ventral gray
I. Motor Pathway
J. Ventricles
K. CSF
L. MeningesSubarachnoid space and Ventricles have CSF
M. Blood Supply and Venous DrainageInternal Carotid & Vertebral arteries = most important arteriesVenous drainages = sinuses are derivations of dura