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The nervous system coordinates actions and transmits signals throughout the body. It consists of the central nervous system (CNS)—the brain and spinal cord—and the peripheral nervous system (PNS), which relays information to and from the rest of the body. Key structures include the cerebral hemispheres, thalamus, hypothalamus, and cerebellum. The nervous system is crucial for processing sensory information and controlling motor functions. Disorders like cerebral vascular accidents and Parkinson's disease illustrate the system's complexity and vulnerability.
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Nervous System Alex Wiemann
Function of Nervous System • Coordinates actions and transmits signals betweenparts of a body
Definition • Central nervous system • brain and spinal cord • integrate information from the periphery and coordinate activities • Peripheral nervous system • provides input to the CNSfrom theperiphery • carries signals to muscles and glands
Simple Reflex Arc • Harmful sensory inputis received by receptors in the skin • Signal is sent to spinal cord • Spinal cord activates motor neuron • Body pulls away from harmful sensory input
Brain Structure and Function • Cerebral hemispheres • occipital lobes: receive and processes visual information • temporal lobes: receive auditory signals and process language • parietal lobes: integrates sensory information and processes information about touch, taste, pressure, pain, and temperature • frontal lobes: integrates and conducts motor activity, conducts speech and thought processes
Brain Structure and Function • Diencephalon • thalamus integrates sensory and motor information • hypothalamus interacts with the autonomic nervous system and maintains homeostasis • Brain stem • Midbrain control posture, walking, and reflexes of eye movements • Medulla: autonomic function including heart rate and breathing • Pons: auditory, vestibular, sensory, and motor systems • Cerebellum: coordination, balance, and motor learning.
Nerve Impulse Resting potential + sensory input threshold potential met nerve depolarization + repolarization = action potential refractory period = hyperpolarization resting potential
Neurotransmitters • NTs are molecules that relay signals from the presynaptic neuron to the postsynaptic cell • Action potential Synapse synaptic cleft postsynaptic membrane NT release
Cerebral Vascular Accidents • Description: blood flow to part of brain disrupted • Types: Ischemic or thrombotic • Signs and symptoms: headache, change in alertness, confusion, difficulty writing, loss of balance, muscle weakness, slurred speech • Prevalence: 3rd most common cause of death in US • Treatment: thrombolytic therapy, anticoagulants/blood thinners, surgery
Parkinson’s Disease • Description: slowly progressive, degenerative disease resulting from loss of dopamine-producing brain cells • Signs and symptoms: tremor, stiffness/rigidity, slow movement, impaired balance • Prevalence: 1 million Americans currently • Treatment: medication (L-dopa, carbidopa), Deep Brain Stimulation, neural grafting
Resources • http://www.news-medical.net/health/What-is-the-Nervous-System.aspx • http://www.news-medical.net/health/Function-of-the-Nervous-System.aspx • http://www.emc.maricopa.edu/faculty/farabee/biobk/biobooknerv.html • http://www.columbia.edu/cu/psychology/courses/1010/mangels/neuro/anatomy/structure.html • http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001740/ • http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5619a2.htm • http://medicalcenter.osu.edu/patientcare/healthcare_services/nervous_system/parkinsons/Pages/index.aspx