Nervous System

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Nervous SystemCNS Lecture 4 Chapter 3 once
again dont be nervous
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CNS - Brain Protects the Brain from External
Internal Forces From 1. Skull
--? External Environment 2. Meninges --?
Skull 3. CSF --? Skull 4. Blood Brain --?
Internal Environment Barrier
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2. Meninges - protective covering
Dura Mater Arachnoid Membrane Pia Mater
(PADs the brain)
Dura mater
Arachnoid Space
Pia mater
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meninges
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Meningitis infection of the meninges
Brain damage Hearing loss Coma
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• 3. Cerebral Spinal Fluid
• Cushions the brain (acts as a buffer)
• Lessen the weight (Buoyancy) on the base of
• the brain (1400g to 50g 1/30th of actual wt)
• Provides nutrients (out too) to the brain
• Continuously manufactured
• Continuously absorbed (jugular vein)

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Cerebral Ventricles
Choroid Plexuses Capillaries
walls or roof of each of the four ventricles
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4. Blood-Brain-Barrier

• Paul Ehrlich (1900)
• inject blue dye into the bloodstream of an
  animal
• only tissue in the periphery turned blue

The BBB is semi-permeable (Glucose)
Functions of the BBB ?Protects the brain from
"foreign substances" ? Protects the brain from
peripheral hormones and amino acids
Cant get in 1. Large molecules 2. Low lipid
(fat) soluble molecules ?lipid soluble molecules
barbiturate rapidly cross through into the
brain. 3. Molecules that have a high electrical
charge to them are slowed.
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The BBB
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Embryonic Development
Before Birth
5 Major Divisions of the Brain
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Forebrain -Telencephalon

• Movement
• Orientation
• Recognition
• Perception of stimuli

Lobes

• Reasoning
• Planning
• Parts of speech
• Movement
• Emotions
• Problem solving

• Visual Processing

• Perception recognition of auditory stimuli
• Memory
• Speech

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Limbic System (emotional brain) Emotion,
Memory Motivation
Forebrain -Telencephalon

• Amygdala Emotions ?fear anger
• Hippocampus Memory
• Septum pleasure centers
• evolutionarily the structure is old

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Forebrain -Telencephalon
Basal Ganglia Hub of Motor Function

• Caudate Putamen
• Globus Pallidus
• Sub Thalamic Nuclei
• Substania Nigra

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Forebrain -Telencephalon

• Cerebral Commissure Corpus Callosum
• largest white matter structure
• 200-250 million contralateral axonal projections
  
• wide, flat bundle of axons beneath the cortex

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Forebrain Diencephalon

• Thalamus Relay Station
• Directs sensory info to higher centers

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Forebrain-Diencephalon

• Hypothalamus 4 Fs
• Maintains homeostasis
• drives associated with survival
• Autonomic NS flight/flight
• Temp
• Water
• Blood pressure
• food regulation
• Sex/reproduction
• Pituitary Gland
• hormones

Fleeing, Fighting, feeding
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Tectum Superior Colliculi
Vision Inferior Colliculi Auditory
Mid Brain Mesencephalon
Tegmentum Substantia Nigra PD - Dopamine

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Substantia Nigra
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Hindbrain

• Pons Regulation of respiration

• Cerebellum little brain
• Fine motor coordination
• Muscle tone

• Medulla Oblongata
• Vital Bodily Function
• HB
• Coughing
• Gag/vomit
• Swallowing

evolutionarily the structure is old