ORGANIZATION OF THE NERVOUS SYSTEM

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ORGANIZATION OF THE NERVOUS SYSTEM

• D. C. Mikulecky
• Professor of Physiology

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COMPUTERS VS BRAINS
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ORGANIZATION OF THE NERVOUS SYSTEM
BRAIN SPINAL CORD
CENTRAL NERVOUS SYSTEM (CNS)
AFFERENT NERVES
EFFERENT NERVES
PERIPHERAL NERVOUS SYSTEM
EXTERO- RECEPTORS
INTERO- RECEPTORS
SOMATIC
AUTONOMIC
EFFECTOR ORGANS
SKELETAL MUSCLES
SMOOTH AND CARDIAC MUSCLES AND GLANDS
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THE CENTRAL NERVOUS SYSTEM CONSISTS OF THE BRAIN
AND SPINAL CORD
BRAINSTEM MIDBRAIN PONS MEDULLA
FOREBRAIN CORTEX THALAMUS AND HYPOTHALAMUS BASIL
GANGLIA
SPINAL CORD
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MAJOR DIVISIONS OF THE CEREBRAL CORTEX
PARIETAL LOBE
FRONTAL LOBE
OCCIPITAL LOBE
TEMPORAL LOBE
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BRAIN VESSICLES

• FIRST AND SECOND (LATERAL)PRIMARY MOTOR AND
  SENSORY CORTEX,LIMBIC SYSTEM, BASAL GANGLIA
• THIRDTHALMUS AND HYPOTHALMUS
• FOURTHCAUDAL BRAIN STEM AND CEREBELLUM

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BRAIN VESSICLES
FRONT
SIDE
LV
LV
III
III
IV
IV
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MAINTENANCE AND PROTECTION OF THE CNS

• Glial Cells physical and metabolic support
• Skull and Spinal Column
• Cerebrospinal fluid
• Blood-brain barrier

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GLIAL CELLS OR NEUROGLIA

• PHYSICAL AND METABOLIC SUPPORT
• 90 OF CELLS IN BRAIN
• FOUR TYPES ASTROCYTES, OLIGODENDROCYTES,
  EPENDYMAL CELLS, AND MICROGLIA

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Skull and Spinal Column

• PROVIDE MECHANICAL SUPPORT
• PROTECTS THE NEURAL AND SUPPORTING TISSUE

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CEREBROSPINAL FLUID

• DENSITY IS THE SAME AS BRAIN
• SHOCK ABSORBER

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Blood-brain barrier

• LIMITS ACCESS OF BLOOD MATERIALS TO BRAIN TISSUE
• PROTECTS BRAIN FROM FLUCTUATIONS IN BLOOD LEVELS

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WHITE AND GRAY

• GRAY MATTER - MAINLY CELL BODIES
• WHITE MATTER - MYELINATED AXONS

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BASAL GANGLIA

• PLAY A COMPLEX ROLE IN THE CONTROL OF MOVEMENT
• INHIBIT MUSCLE TONE THROUGHOUT BODY
• SUPPRESS USELESS OR UNWANTED PATTERNS OF MOVEMENT

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THALAMUS

• RELAY STATION
• HELP US DIRECT OUR ATTENTION
• FILTERS OUT INSIGNIFICANT SIGNALS

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HYPOTHALAMUS

• REGULATES HOMEOSTATIC FUNCTIONS
• THIRST AND URINE OUTPUT
• FOOD INTAKE
• HORMONE SECRETION
• BODY TEMPERATURE
• AUTONOMIC NERVOUS SYSTEMS COORDINATING CENTER

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LIMBIC SYSTEM

• AMYGDALA
• HIPPOCAMPUS
• CORPUS CALLOSUM
• FORNIX
• CINGULATE GYRUS

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LIMBIC SYSTEM

• COMPLEX NETWORK OF FOREBRAIN STRUCTURES
• EMOTIONS
• BASIC SURVIVAL
• SOCIOSEXUAL BEHAVIOR
• MOTIVATION
• LEARNING

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THE SPINAL CORD IN SOMATIC SENSORY FUNCTION

• WHITE AND GREY MATTER
• SEGMENTAL ORGANIZATION

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SPINAL CORD
DORSAL HORN
DORSAL
GRAY MATTER
DORSAL ROOT GANGLION
LATERAL
VENTRAL HORN
WHITE MATTER
SPINAL NERVE
VENTRAL
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TOUCH AND PRESSURE
DORSAL COLUMN PATHWAY
INCOMONG SENSORY NERVE TRAVELS UPWARD IN THE
DORSAL COLUMN AND SYNAPSES IN THE DORSAL COLUMN
NUCLEUS
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PAIN AND TEMPERATURE
ANTEROLATERAL PATHWAY
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SEGMENTAL STRUCTURE OF SPINAL NERVES
DERMATOMES
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THE THALAMUS IN SOMATIC SENSATION

• MAJOR SITE FOR RECEIVING SENSORY INFORMATION
• VENTRAL POSTERIOR LATERAL NUCLEUS (VPL)
• SENDS SENSORY INFORMATION TO THE CORTEX

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THE THALAMUS IN SOMATIC SENSATION
SENSORY NEOCORTEX
MEDIAL LEMNISCUS
DORSAL COLUMN NUCLEI
MEDULLA
DORSAL COLUMN
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SOMATOTOPIC ORGANIZATION OF THE SENSORY CORTEX
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THE SOMATOSENSORY CORTEX
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CORTICAL AREAS INVOVED IN MOTOR CONTROL
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SOMATOTOPIC ORGANIZATION OF THE MOTOR CORTEX
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MOTIVATIONAL SYSTEMS

• HUNGER
• THIRST
• SEXUAL BEHAVIOR

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HUNGER
GLUCOSE RECEPTORS IN HYPOTHALAMUS
REDUCED AVAILABILITY OF GLUCOSE
SHORT TERM
MECHANO- RECEPTORS IN STOMACH
CONTRACTIONS OF EMPTY STOMACH
HUNGER
LACK OF FOOD
LOW TRIGLYCERIDE LEVELS IN FAT CELLS
LONG TERM
PANCREAS
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THIRST
OSMORECEPTORS IN SUPRAOPTIC AND
SUPRA- VENTRICULAR NUCLEI OF HYPOTHALAMUS
THIRST
WATER DEFICIENCY
WATER RETENTION BY KIDNEY
ADH SERETION BY PITUITARY
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SEXUAL BEHAVIOR

• ANTERIOR HYPOTHALAMUS ORGANIZES RESPONSES TO
  PHERMONES
• OLIFACTORY CUES SENT TO PYRIFORM CORTEX AND
  AMYGDALA AND INDIRECTLY TO HYPOTHALAMUS
• ANDROGENS DETERMINE RELEASE OF LEUTINIZING
  HORMONE- CONSTANT OR CYCLIC