organization of the nervous system d. c. mikulecky professor of physiology
DESCRIPTION
ORGANIZATION OF THE NERVOUS SYSTEM BRAIN SPINAL CORD CENTRAL NERVOUS SYSTEM (CNS) PERIPHERAL NERVOUS SYSTEM AFFERENT NERVES EFFERENT NERVES EXTERO- RECEPTORS INTERO- RECEPTORS SOMATICAUTONOMIC EFFECTOR ORGANS SKELETAL MUSCLES SMOOTH AND CARDIAC MUSCLES AND GLANDSTRANSCRIPT
ORGANIZATION OF THE NERVOUS SYSTEM
D. C. MikuleckyProfessor of Physiology
COMPUTERS VS BRAINS
FEATURE COMPUTERS BRAINARCHITECTURE von NEUMAN UNKNOWN, BUT
COMPLEXOPERATION SEQUENTIALLY PARALLEL &
SEQUENTIALTIME SCALE MICRO TO NANO
SECSEC TO MSEC
PROCESSORS 1 TO HUNDREDS 10-100 BILLION
INPUT/OUTPUT A FEW PORTS 5-10 MILLION
STATES WELL DEFINED ILL DEFINED(NOISENEEDED)
HABITUATION NONE FUNDAMENTALFEATURE
ORGANIZATION OF THE NERVOUS SYSTEM
BRAINSPINAL CORD
CENTRALNERVOUSSYSTEM (CNS)
PERIPHERALNERVOUS SYSTEM
AFFERENT
NERVES
EFFERENT
NERVES
EXTERO-RECEPTORS
INTERO-RECEPTORS
SOMATIC AUTONOMIC
EFFECTORORGANS
SKELETALMUSCLES
SMOOTH AND CARDIAC MUSCLES AND GLANDS
THE CENTRAL NERVOUS SYSTEM CONSISTS OF THE BRAIN AND SPINAL
CORDBRAINSTEM:MIDBRAINPONSMEDULLA
FOREBRAIN:CORTEXTHALAMUS AND HYPOTHALAMUSBASIL GANGLIA
SPINALCORD
MAJOR DIVISIONS OF THE CEREBRAL CORTEX
FRONTAL LOBEPARIETAL LOBE
OCCIPITAL LOBE
TEMPORAL LOBE
BRAIN VESSICLES
• FIRST AND SECOND (LATERAL):PRIMARY MOTOR AND SENSORY CORTEX,LIMBIC SYSTEM, BASAL GANGLIA
• THIRD:THALMUS AND HYPOTHALMUS
• FOURTH:CAUDAL BRAIN STEM AND CEREBELLUM
BRAIN VESSICLESFRONT SIDE
III
LV
III
IV
LV
IV
MAINTENANCE AND PROTECTION OF THE CNS
• Glial Cells: physical and metabolic support• Skull and Spinal Column• Cerebrospinal fluid• Blood-brain barrier
GLIAL CELLS OR NEUROGLIA:
• PHYSICAL AND METABOLIC SUPPORT
• 90% OF CELLS IN BRAIN• FOUR TYPES: ASTROCYTES,
OLIGODENDROCYTES, EPENDYMAL CELLS, AND MICROGLIA
Skull and Spinal Column
• PROVIDE MECHANICAL SUPPORT
• PROTECTS THE NEURAL AND SUPPORTING TISSUE
CEREBROSPINAL FLUID
• DENSITY IS THE SAME AS BRAIN
• SHOCK ABSORBER
Blood-brain barrier
• LIMITS ACCESS OF BLOOD MATERIALS TO BRAIN TISSUE
• PROTECTS BRAIN FROM FLUCTUATIONS IN BLOOD LEVELS
WHITE AND GRAY
• GRAY MATTER - MAINLY CELL BODIES
• WHITE MATTER - MYELINATED AXONS
BASAL GANGLIA
• PLAY A COMPLEX ROLE IN THE CONTROL OF MOVEMENT
• INHIBIT MUSCLE TONE THROUGHOUT BODY
• SUPPRESS USELESS OR UNWANTED PATTERNS OF MOVEMENT
THALAMUS
• RELAY STATION• HELP US DIRECT OUR ATTENTION• FILTERS OUT INSIGNIFICANT
SIGNALS
HYPOTHALAMUS
• REGULATES HOMEOSTATIC FUNCTIONS
• THIRST AND URINE OUTPUT• FOOD INTAKE• HORMONE SECRETION• BODY TEMPERATURE• AUTONOMIC NERVOUS SYSTEM’S
COORDINATING CENTER
LIMBIC SYSTEM
• AMYGDALA• HIPPOCAMPUS• CORPUS CALLOSUM• FORNIX• CINGULATE GYRUS
LIMBIC SYSTEM
• COMPLEX NETWORK OF FOREBRAIN STRUCTURES
• EMOTIONS• BASIC SURVIVAL• SOCIOSEXUAL BEHAVIOR• MOTIVATION• LEARNING
THE SPINAL CORD IN SOMATIC SENSORY FUNCTION
• WHITE AND GREY MATTER• SEGMENTAL ORGANIZATION
SPINAL CORDDORSAL HORN GRAY
MATTER
DORSAL
VENTRALSPINAL NERVE
DORSALROOTGANGLION
VENTRALHORN
WHITEMATTER
LATERAL
TOUCH AND PRESSUREDORSALCOLUMNPATHWAY
INCOMONG SENSORY NERVE TRAVELS UPWARD IN THE DORSAL COLUMN AND SYNAPSES IN THE DORSAL COLUMN NUCLEUS
PAIN AND TEMPERATURE
ANTEROLATERALPATHWAY
SEGMENTAL STRUCTURE OF SPINAL NERVES
DERMATOMES
THE THALAMUS IN SOMATIC SENSATION
• MAJOR SITE FOR RECEIVING SENSORY INFORMATION
• VENTRAL POSTERIOR LATERAL NUCLEUS (VPL)
• SENDS SENSORY INFORMATION TO THE CORTEX
THE THALAMUS IN SOMATIC SENSATION
DORSAL COLUMN
MEDULLA
MEDIALLEMNISCUS
SENSORYNEOCORTEX
DORSAL COLUMNNUCLEI
SOMATOTOPIC ORGANIZATION OF THE SENSORY CORTEX
THE SOMATOSENSORY CORTEX
CORTICAL AREAS INVOVED IN MOTOR CONTROL
SOMATOTOPIC ORGANIZATION OF THE MOTOR CORTEX
MOTIVATIONAL SYSTEMS
• HUNGER
• THIRST
• SEXUAL BEHAVIOR
HUNGER
LACK OF
FOOD
REDUCEDAVAILABILITYOF GLUCOSE
CONTRACTIONS OF EMPTYSTOMACH
LOWTRIGLYCERIDELEVELSIN FAT CELLS
GLUCOSE RECEPTORSIN HYPOTHALAMUS
MECHANO-RECEPTORSIN STOMACH
PANCREAS
HUNGER
THIRST
WATERDEFICIENCY
OSMORECEPTORSIN SUPRAOPTICAND SUPRA-VENTRICULARNUCLEI OFHYPOTHALAMUS
THIRST
ADHSERETIONBY PITUITARY
WATERRETENTION BY KIDNEY
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