Cns Anatomy Slides
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Transcript of Cns Anatomy Slides
Brain Anatomy Slides courtesy of Dr. Maria Rubio
General Rule: The functional and anatomical organization of
sensory processing networks is hierarchical
1st order neuron
3rd order neuron
2nd order neuron
Figure 13-2
Gross Anatomy of the Spinal Cord
Figure 16-1 M
Spinal Nerves:
� 8 Cervical nerves
� Neck, shoulder, arms and hands
� 12 Thoracic nerves
� Shoulders, chest, and upper abdomen
� 5 lumbar nerves
� Lower abdomen, hips and legs
� 5 sacral nerves
� Genitals and lower digestive tract
Gross Anatomy of the Spinal Cord Cross Section:
� Gray matter� Gray due to cell bodies
� In CNS, gray matter also = synapses
� White Matter� White due to myelin; =
axons (both myelinated and unmyelinated)
� Dorsal Horn
� Ventral Horn
� Ventral Root
� Dorsal Root� Cell bodies of unipolar
sensory neurons
� No synapses
� Dorsal Root Ganglion
Sectional
Anatomy of the
Spinal Cord
Figure 6-41 V; 16.3M
See 16.4M
Note functional organization of gray matter
Fiber Tracts: Ascending (Sensory) Tracts
� Dorsal Columns
� Fasciculus cuneatus
� Fasciculus gracilis
� Anterolateral columns
� E.g., spinothalamic tracts
� Spinocerebellar tracts
Note functional organization of WHITE
matter
Fiber Tracts: Descending (Motor) Tracts
� Ventromedial System
� Reticulospinal
� Vestibulospinal
� Tectospinal
� Anterior Corticospinal
� Dorsolateral System
� Rubrospinal
� Lateral Corticospinal
Pyramidal; extrapyramidalterminology is outdated!
Spinal NervesPeripheral Nerve Structure
Dermatomes
Figure 16.6 M
Nerve Plexuses� A network of
interweaving anterior rami of spinal nerves
� Rami (pl.) ramus –primary division of a nerve or blood vessel
� Cervical plexus
� Brachial plexus
� Lumbar plexus
� Sacral plexus
Cervical Plexus
� C1 – C4
� Innervates neck (sensory and motor)
� Phrenic nerve (C3 - 4)
� Innervates diaphragm (so you can breathe!)
Figure 16.8 M
Brachial Plexus� C5 – T1
� Sensory/motor innervation of upper extremity
� More complex than cervical plexuses
� Anterior rami
� Trunks
� Divisions
� Cords
Figure 16.9 M
Lumbar Plexus� L1 – L4
� Supply lower limb of each side
� Less complex than brachial plexus
Figure 16.10 M
Sacral Plexus� L4 – S4
� Supply gluteal region, plevis, perineum, and lower limb of each side
� Together with Lumbar plexus as lumbosacral plexus
Figure 16.11 M
Components of Reflex Arc
See also Figure 16.12 M
Example of Deep Tendon Reflex
Patellar tendon (“knee jerk”) reflexClinical usefulness
Monosynaptic (Knee Jerk) and Disynaptic
(Flexor Withdrawal) Reflexes
Figure 16.13 M
�Clinical usefulness of reflexes –see table 16.6 M
�Muscle tone
Slides courtesy of Dr. Maria Rubio
Sagittal Plane
Coronal Plane
Posterior View
Brainstem
� Brainstem � Medulla
� Pons
� Midbran
� Rigidly programmed, automatic behaviors
� Medulla
• Centers for cardiovascular and respiratory regulation
• Cranial nerve nuclei
• Reticular formationMedulla
Pons
Pons �
• Cranial nerve nuclei, tracts
• Reticular formation
Midbrain
� Midbrain
• Superior Colliculus
• Eye / Head orientation movements
• Inferior Colliculus
• Tracts, nuclei
• Reticular formation
RETICULAR FORMATION ����
• > 100 Nuclei
• Extends throughout brainstem
• Receives info from all over brain
• Projects throughout brain
Cerebellar peduncles
• Receives visual, vestibular, proprioceptive input
• spinocerebellar tracts
• Functions include coordination
Cerebellum
Figure 15-22 M
Posterior View
(Brainstem and) DiencephalonDiencephalon
DiencephalonEpithalamus
Thalamus
• Sensory relay center
Hypothalamus
• “Homeostasis”
ThalamusSagittal
Coronal
HypothalamusSagittal
Coronal
Autonomic Functions
Superior View Anterior View
Posterior View
Lateral View
Ventral View
Cerebral Hemispheres
Superior View
Anterior View
Posterior View
Cortex: Correlate Lobes with Function
Figure 15-1 M
� Frontal� Motor, speech, personality, emotion
� Frontal lobotomies� Parietal
� Somatosensory cortex, voluntary movement
� Occipital� Vision
� Temporal� Hearing, balance, visual processing
ridges
Shallow separation
Lateral View
White Fiber Tracts� Projection fibers
� Commisural fibers
� Association fibers
Frontal
Human Brain: coronal sections
Caudal
Basal Ganglia� Nuclei important in motor control
� Caudate, putamen, globuspallidus
� Subthalamic nuclei, substantia nigra
Internal Capsule
� Between putamen-globuspallidus and thalamus
� Major projection of fibers to/from cortex
� Common CVA (stroke) site
Rhinencephalon� Phylogeneticallyancient cortex� Olfactory bulb + tract
� Fornix
� Limbic system� Amygdala
� Hippocampus
Limbic System
� Emotional brain� Shape of a ring (around diencephalon)� Cingulate gyrus� Parahippocampalgyrus
� Hippocampus� Amygdala� Olfactory bulbs� Fornix� Diencephalon nuclei
Cerebral Hemispheres: Frontal section at a:Gray matter (cell bodies – in CNS, also SYNAPSES)White matter (axons)
Corpus Callosum: connects cerebral hemispheres (with commisural fibers)
Figure 15-3 M
Cerebellum and Brainstem (section at b):Gray matter (cell bodies + synapses)White matter (axons)
Figure 15-3 M
Medulla (lower brainstem; section at c):Gray matter (cell bodies + synapses)White matter (axons)
Figure 15-3 M
Spinal Cord (section at d):Gray matter (cell bodies + synapses)White matter (axons)
Figure 15-3 M
Ventral View
Cranial Nerves
See lecture outline for functions of each.
Research Martin StynerVentricles (with CSF)The brain is a hollow organ
Brain Ventricles
Figure 15-6 M
Cranial Meninges
Figure 15-5 M
Dura mater ArachnoidArachnoidPia mater
Cranial Meninges
Figure 13–3
Spinal Meninges
Figure 16.2 M
Cerebral Spinal Fluid (CSF)� Surrounds brain & spinal
cord; circulates through ventricles
� Cushions; protection
� Formed in choroid plexus by ependymal cells
� Blood-brain barrier limits the flow of solutes into CSF
� Materials which easily pass across the BBB:
� Glucose, AAs, certain ions, fatty acids, nicotine, CO, CO2
� BBB restricts these materials:
� Blood, wastes (e.g. urea), proteins, K+ ions
Recall role of ASTROCYTES and TIGHT JUNCTIONS in forming BBB
See also Figure 15-8 M
Vascularization
Internal Carotid A.Vertebral A.
Basilar a
Posterior
Cerebral A.
Anterior
Cerebral A.
Middle
Cerebral A.
The major arterial supply to the brain
Circle of Williscollateral circulation
Posterior cerebral art.
Middle cerebral art.Anterior cerebral art.