Central Nervous System Notes complex control complex high level neurons found in brain spinal cord coordinates motor reflexes cerebellum little cerebrum controls balance body pons controls automatic functions links medulla oblongata contains respiration circulation receive process visual information controls eye ear reflex information diencephalons thalamus hypothalamus thalamus relays info between spinal cord and cerebrum hypothalamus controls emotions pituitary gland cerebrum telencephalon dominant part of mammalian Evolution of vertebrate brain sponges are only multicellular animals w o nerves cnidarians have simplest nervous systems nerve net no control association flatworms simplest animals w association in nervous system bigger mass of nervous tissue beginnings of brain interneurons tracts added to brain as it evolved interneurons hindbrain rhombencephalon extension of spinal cord position cerebellum medulla oblongata w other parts of brain midbrain mesencephalon consists of mostly optic lobes that forebrain prosencephalon processes most of sensory ascending tracts carry sensory info to brain descending tracts carry impulses from brain to motor neurons human forebrain divided into 2 hemispheres connected by corpus callosum each hemisphere receives info from opposite side cerebral cortex layer of gray matter on outer surface of cerebrum contains 10 of all neurons in brain folded wrinkled to increase surface area primary motor cortex right in front of central sulcus brain primary somatosensory cortex right behind central crease controls mov t sulcus receives info from sensory neurons of skin muscles parietal somatosensory lobes auditory cortex in temporal lobe visual cortex in occipital lobe association cortex used for higher mental activities basal ganglia collections of cell bodies dentrites that produce gray matter islands receives info from ascending tracts motor commands from cerebrum cortex sends info to spinal cord to control mov t damaged ganglia Parkinson s thalamus main area of senses especially pain receives visual auditory somatosensory info relays info to occipital visual temporal auditory hypothalamus controls instinct regulates body temperature hunger thirst emotion controls pituitary gland regulates other endocrine glands limbic system responsible for emotional responses includes hypothalamus hippocampus may control spinal cord cable of neurons going from brain through backbone protected by vertebral column and meninges membrane layers that also cover the brain inner zone gray matter consists of interneuron motor neuron neuroglia cell bodies unmyelinated cell bodies outer zone white matter consists of sensory axons in dorsal column and motor axons in ventral column myelinated axons controls reflexes sudden involuntary muscle mov t doesn t require higher level processing of info only uses a few neurons very fast monosynaptic reflex arc simplest reflex like knee jerk memories amygdala reflex sensory nerve connects directly to motor neuron most reflexes usually involve an interneuron between sensory motor neurons regeneration implanted nerve axons can t penetrate spinal cord tissue factor in spinal cord inhibits nerve growth use of fibroblast growth factor shows limited improvement in neuron regeneration ability
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