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Anatomy and Physiology Blake Austin College Licensed Vocational Nursing Program Semester 1 Central Nervous System © 2009 Delmar, Cengage Learning Objectives • • • • • • • • Describe the functions of the central nervous system List the main divisions of the central nervous system Identify the parts of the brain Describe the structure of the brain and spinal cord Describe the functions of the parts of the brain Describe the functions of the spinal cord Describe disorders of the brain and spinal cord Define the key words that relate to this chapter © 2009 Delmar, Cengage Learning Divisions of the Nervous System • Central nervous system – Brain – Spinal cord • Peripheral nervous system – 12 pairs of cranial nerves – 31 pairs of spinal nerves • Autonomic nervous system – Peripheral nerves and ganglia © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning CNS Functions • Communication and coordination system in the body – Receives messages from stimuli all over the body – Brain interprets the message – Brain responds to the message and carries out an activity • Seat of intellect and reasoning http://www.youtube.com/watch?v=kMKc8nfPATI © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning The Nerve Cell • Called the neuron • Nucleus, cytoplasm, and cell membrane • Dendrites – Carry messages to the cell body • Axons (only one per cell) – Carry messages away from the cell body © 2009 Delmar, Cengage Learning The Nerve Cell © 2009 Delmar, Cengage Learning Nervous Tissue/Cells • Neuroglia or Glial cells – Cells that insulate, support and protect the neurons • Neurons – Conducting cell that transmits impulses Sensory or afferent Motor or efferent Associative or interneurons • Membrane excitability – Resting membrane Sodium-potassium pump maintains a negative charge inside the cell – Stimulation Depolarization or influx of sodium ions into the cell Repolarization or influx of potassium out of the cell © 2009 Delmar, Cengage Learning Neuroglia and Neuron © 2009 Delmar, Cengage Learning Synapse • When messages go from one cell to the next cell • Synaptic cleft • Neurotransmitters © 2009 Delmar, Cengage Learning Synapse © 2009 Delmar, Cengage Learning The Brain • Weighs about 1400 grams or 3 pounds • 100 billion neurons • Without oxygen, brain damage occurs within 4-8 minutes © 2009 Delmar, Cengage Learning • • • • Cerebrum Diencephalon Cerebellum Brain stem Memory • Storage of old and new information • Short or long term memory © 2009 Delmar, Cengage Learning Hippocampus = memory router © 2009 Delmar, Cengage Learning Coverings of the Brain • Three meninges – Dura mater • Outer brain covering inside of the skull – Arachnoid mater • Middle layer – Pia mater • Covers the brain surface • Consists of blood vessels held together by fine connective tissue © 2009 Delmar, Cengage Learning Coverings of the Brain = Meninges © 2009 Delmar, Cengage Learning Ventricles of the Brain • Four lined cavities filled with cerebrospinal fluid – 1st and 2nd – Right and left lateral ventricles – 3rd – Connected to the lateral ventricles by the interventricular foramen – 4th – Connected to the 3rd by the cerebral aqueduct • Choroid plexus © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning Cerebrospinal Fluid (CSF) • Formed inside the four ventricles • Transports nutrients to, and removes metabolic waste products form, the brain cells • Blood-brain barrier • CSF fluid bathes the brain and the spinal cord ultimately circulating into the bloodstream via the venous structures in the brain • Lumbar puncture © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning Additional Parts of the Brain And Their Functions. © 2009 Delmar, Cengage Learning Cerebrum • • • • Largest part of the brain Weighs about 2 pounds Cerebral cortex Two hemispheres – Right and left • Divided by a longitudinal fissure – Each hemisphere is divided into four lobes © 2009 Delmar, Cengage Learning Cerebral Lobes and Functions © 2009 Delmar, Cengage Learning Limbic System and Diencephalon • Located between the cerebrum and the midbrain • Thalamus – Relay station for incoming and outgoing nerve impulses • Hypothalamus – Part of the limbic system and is considered the be the “brain” of the brain © 2009 Delmar, Cengage Learning Limbic System and Diencephalon © 2009 Delmar, Cengage Learning Hypothalamus • Autonomic nervous control • Cardiovascular control • Temperature control • Appetite control • Water balance • • • • • Manufacture of oxytocin Gastrointestinal control Emotional state Sleep control Mind-over-body experiences http://www.youtube.com/watch?v=a2bBXDFUHhk © 2009 Delmar, Cengage Learning Hypothalamus © 2009 Delmar, Cengage Learning Cerebellum • Located behind the pons and below the cerebrum • Right and left cerebellar hemispheres connected by vermis • Communicates with the rest of the CNS by three pairs of tracts called peduncles © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning Cerebellar Function • Maintenance of balance • Maintenance of muscle tone • Coordination of muscle movements http://www.youtube.com/watch?v=D7u9xFy1GiI http://www.youtube.com/watch?v=eBvzFkcvScg © 2009 Delmar, Cengage Learning Brain Stem • Midbrain • Pons • Medulla oblongata © 2009 Delmar, Cengage Learning Spinal Cord • Begins at foramen magnum of the occipital bone • Ends at the second lumbar vertebrae • 31 pairs of spinal nerves • Protected by meninges and other tissues • Functions – Carry messages from the sensory neurons to the brain for interpretation and the response is carried back from the brain through the motor neurons to the muscles and glands – Serve as the reflex center for the body • © 2009 Delmar, Cengage Learning © 2009 Delmar, Cengage Learning Effects of Aging • • • • Slowing nerve conduction Loss of brain size Slowing of reaction time Changes in sleep patterns © 2009 Delmar, Cengage Learning Disorders • • • • • • • • Meningitis Encephalitis Epilepsy Cerebral palsy Poliomyelitis Hydrocephalus Parkinson’s disease Essential tremor © 2009 Delmar, Cengage Learning • • • • • • • Multiple sclerosis West Nile virus Dementia Alzheimer’s disease Brain tumors Hematoma Spinal cord injuries – Quadriplegia – Paraplegia Prefixes/suffixes to remember • Mening• -itis © 2009 Delmar, Cengage Learning • • • • ParaQuadra-plegia -paresis
