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Neurology
Lecture 1Part 2
Central Nervous System
• Brain• Spinal Cord• Control center for
entire system
Brain
• Skull– Ridged vault
• Plates and Fissures– Occipital – Parietal– Temporal– Frontal
The Meninges
• Function– Support– Protect– Nourish
• Dura mater• Arachnoid
– Choroid Plexus– Cerebral-spinal fluid
(CSF)
• Pia Mater
Brain – 3 main areas
• Cerebrum– Coordination of stimuli
• Brainstem– Midbrain– Pons– Medulla oblongata
• Cerebellum– Control muscle
movement
Cerebrum
• Cerebral cortex• Rt. & Lt. hemisphere• Receives & analyze
impulses• Control voluntary
movement• Stores knowledge
4 Major Lobes
• Frontal• Parietal• Temporal• Occipital
Frontal Lobe - Cerebrum
• Personality• Intellectual functioning• Conceptualization• Abstraction• Affect• Judgment• Inhibitions• Write
Parietal Lobe - Cerebrum
• Perception & interpretation of sensory info
• Recognize body parts• Sensation• Spatial relationships
Temporal Lobe - Cerebrum
• Memory (short term)• Hearing• Taste• Smell• Auditory integration• Understanding spoken word• Behavior and emotional
control
Occipital Lobe - Cerebrum
• Visual center• Understanding of
written language
Basal Ganglia
• Deep within the cerebrum
• Function– Control postural
adjustments (subconscious)
– Fine motor movements (esp. hands & lower ext.)
Speech Centers
• Broca’s Area– Frontal lobe– Controls verbal &
expressive speech– Coordinates the mouth,
tongue and larynx– Damaged can not
speak
Speech Centers
• Wernicke’s area– Temporal lobe– Responsible for
reception and understanding of language
– Damage can not understand speech
Left-side Brain
• Verbal communication• Linguistics /language• Arithmetical• Calculating• Analytical• Problem solving• Reading• Writing
Right-side Brain
• Geometric• Spatial• Visual• Patterns• Music• Perception of physical
environment• Art• Non-verbal communication• Spiritual
Corpus Callosum - Cerebrum
• Responsible for transmission of info from one side of the brain to the other
Diencephalon
• Thalamus– Translates impulses into
• Pain• Temperature• Touch sensation• Pleasant and
unpleasant feelings– Complex reflex
movement
Diencephalon
• Hypothalamus– Nervous + endocrine
system– Feelings of rage /anger– Temperature– Sleep– Thirst– Appetite/hunger– Respiration– Blood pressure– Osmolarity of body fluids
Diencephalon
• Pituitary Gland– Endocrine system– Master gland
Cerebral Cortex / Cerebrum
• All stored information• 4 speech centers• Motor & sensory areas• Vision & hearing
Cerebral Cortex / Cerebrum
• CNS produces electrical waves
• EEG
Brainstem
• Connects brain with spinal cord
• Structures– Midbrain
• Upper brain stem• Motor movement• Postural reflexes• Relay for sight and
hearing
Brainstem
• Structures– Midbrain– Pons
• Btw midbrain and medulla
• Pneumotaxic center– Medulla oblongata
Brainstem
• Medulla oblongata– Below ponds– Vital reflexes– Cardiac center– Respiratory center– Cough, swallowing,
hiccupping vomiting– Pyramidal tracts
Cerebellum
• Lesser brain• Controls skeletal
muscles coordinated movement, equilibrium and erect posture
Spinal Cord – CNS
• Continuous with brain stem
• Extend to L-1orL-2• Filum Terminal• Lumbar Punctures
L3-4
Spinal Cord - CNS
• Divided into Rt & Lt hemispheres
Peripheral Nervous System
• Contains– Cranial nerves– Spinal nerves
• Location• Function
– Sensory impulses from PNS CNS
– Motor response from CNS PNS
• Key word:– Nerves
Peripheral Nervous System
• Consists of– 12 pairs of cranial
nerves– 31 pairs of spinal nerves
• Cervical = 8• Thoracic = 12• Lumbar = 5• Sacral = 5• Coccygeal = 1
Peripheral Nervous System
• Myelin Sheath– Insulation– Increases velocity of
impulse
Spinal Nerves
• Dorsal/Posterior Horn– Sensory
• Vental/Anterior Horn– Motor
Thought Question
When the doctor checks your reflexes in your leg: Does the impulse:
A. travel to you spinal cord brain Brain says kick impulse to your spinal cord impulse to your knee kick OR
B. Impulse travel to your spinal cord spinal cord says kick impulse back to knee kick
Spinal Reflexes
• Forms reflex arc• Automatic
PNS Somatic & Autonomic NS
• Somatic NS– Acetylcholine speeds impulses– Connects CNS to skin & skeletal muscles – Conscious activities - Voluntary
• Autonomic NS– Connects CNS to visceral organs– Unconscious activates– Divided
• Sympathetic nervous system• Parasympathetic nervous system
Schematic Diagram of the Peripheral Nervous System
PNS comprised of Cranial and Spinal Nerves
Somatic Nervous SystemProcess: VoluntaryFunction: Respond to changes in external environmentEffector site: skeletal muscle
Autonomic Nervous systemProcess: InvoluntaryFunction: Respond to changes in the internal environmentEffector sites: Internal organs
Sympathetic NS Parasympathetic NS
Autonomic Nervous System
Sympathetic Nervous System
Chemical Process: AdrenergicFunction: EnergizeScope of Response: Global
Parasympathetic Nervous SystemChemical Process: CholinergicFunction: StabilizeScope of Response: Local
Sympathetic NS Parasympathetic NS
Rate Heart rate
Constricts Abd. muscles
Dilates
Dilates Vessels of Skeletal muscles
0
Dilates Bronchi Constricts
secretions Lung secretions
secretions
Peristalsis
Salivary secretions
Sympathetic NS Parasympathetic NS
Closes Anal sphincter Opens
Relaxes Bladder Contracts
Closes Urinary sphincter
Opens
Dilate Pupil Constrict
far vision Eye accommodatio
n
near vision
secretions Pancreas secretions
Release glucose
Liver 0
secretions Adrenal Medulla
0
Cerebrospinal fluid (CSF)
• The ventricles manufacture and absorb CSF – primarily choroid plexus
• Circulated in the subarachnoid space
CSF Function
• Cushion• Carries nutrients• Helps maintain inter-
cranial pressure
CSF Characteristics
• Colorless• Average: 100-150
cc• Contains
– H2O– Glucose– Na+
– Cl-
– K+
– No RBC’s– WBC – (trace 0-5)
Circulation of brain and spinal cord
• 2 internal carotid arteries
Circulation of brain and spinal cord
• 2 internal carotid arteries
• Vertebral arteries
Circulation of brain and spinal cord
• 2 internal carotid arteries
• Vertebral arteries• Circle of Willis
Brain circulation
• Does not store nutrients• Can adjust own blood flow
in response to BP– Increase CO2
• Vasodilate– Decrease O2
• Vasodilate – Decrease in pH
• Vasodilate
• Large amounts of O2
Blood brain barrier
What do we know about capillaries?
• Permeable / thinBrain capillaries lined with
endothelial cells tight junction
Permeability of Blood Brain Barrier
Permeable:• O2• CO2• WaterSlight Permeable:• Electrolytes• GlucoseImpermeable to:• Most drugs• proteins