BASIC ORGANIZATION OF THE NERVOUS SYSTEM (Dr. Sarfati) Aug. 17 Nervous System -unique and complex -neurological disease are non palpable -subserves language, comprehension, memory, intellect, personality, movement A.) Central N.S Brain has 2 hemispheres Subcortical structures: Thalamus Hypothalamus Brain stem- links cerebral hemisphere to the spinal cord -composed of the midbrain,pons, medulla Cerebellum- for balance and coordination Spinal cord
Hypothalamus and pituitary gland- central component of the autonomic N.S
B.) Peripheral N.S -nerve, neuromuscular junction, muscle **Autonomic N.S Cerebral hemisphere A. Cerebral cortex -outer -gray in color because it contains neurons Has convolutions (gyrus) and invaginations (sulcus) B. Subcortex-inner -axons of the neurons from the cortex which are myelinated that’s why they appear white in color (white matter) Nuclei in the subcortex: internal capsule & Basal nuclei Central sulcus- divides frontal from the parietal lobe Parieto-occipital lobe-divides parietal lobe and occipital lobe Frontal lobe -movement, judgement, gaze center, micturition Pre-central gyrus -motor strip Parietal lobe -sensation Occipital -vision Temporal -hearing, language, comprehension & memory Subcortex is composed of: a. Thalamus- relay center for sensation except smell b. Hypothalamus-visceromotor function, sexual behavior, hormonal control, temperature control
c. Internal capsule- contains axons of the motor neurons d. Basal nuclei Brain stem: -midbrain, pons, medulla -cranial nerves except I & II -descending (motor) tracts to spinal cord, ascending (sensory) tracts to cortex Midbrain -contain nuclei for visual and auditory reflexes Pons -wakefulness Medulla -respiration, heart rate and visceral functions Cerebellum -coordination of movement -balance for smooth movement Spinal cord -links brain with the peripheral NS through pathways and tracts -motor and sensory fiber **from the foramen magnum, the brain continues to the spinal cord **there are lumbar and cervical enlargements because you’ll need more motor neurons in your upper and lower extremities **The spinal cord is shorter than the vertebral column; ends at the higher level of lumbar 1 ** the white matter of the spinal cord is on the outer portion -neurons inside, axons outside PERIPHERAL NERVOUS SYSTEM -nerves (31 spinal nerves, 12 cranial nerves) -neuromuscular junction -muscle 7 cervical bones 8 cervical nerves 5 thoracic bones 12 thoracic nerve Posterior nerve root - sensory Anterior nerve root-motor -join together to form spinal nerve **cranial nerves I Olfactory- smell -onLy nerve that doesn’t go through thalamus
Neuron -dendrite- receiving part of the neuron -axon -cell body -nucleus Neuroglial cells- supporting cells Oligodendrocyte-responsible for myelination in the CNS **PNS- Schwann cell that myelinates axons Astrocyte- support Microglial cells- immune cells in the brain; only glial cell that comes from the ectoderm. It comes from the mesoderm
