Nervous System The Nervous System An overview Includes Nerve tissue Sense organs Functions to Sense environment Process information it receives Respond to information 1 Copyright 2009 Pearson Education, Inc. 2 Outline Central VS Peripheral Nervous Systems Peripheral Nervous System Autonomic NS Somatic NS Autonomic Nervous System Parasympathetic NS Sympathetic NS Reflex Actions Central Nervous System (CNS) Brain Spinal Cord Peripheral Nervous System (PNS) Nervous tissue outside brain and spinal cord Sensory organs Copyright 2009 Pearson Education, Inc. 3 1
Peripheral Nervous System Afferent Division (Sensory) Central Nervous System Efferent Division (Motor) Neurons of the Peripheral Nervous System Carrying messages to or from the CNS 2 types Afferent = Sensory Efferent = Motor Copyright 2009 Pearson Education, Inc. 6 Neurons in the Central Nervous System Interneurons Located between sensory and motor neurons within the CNS Integrate and interpret sensory signals Peripheral Nervous System Somatic Nervous System Voluntary functions Autonomic Nervous System Involuntary functions Copyright 2009 Pearson Education, Inc. 7 Copyright 2009 Pearson Education, Inc. 8 2
Peripheral Nervous System Autonomic Nervous System Parasympathetic Rest & Digest Sympathetic Fight or Flight Stress Responses The PNS - Parasympathetic Constricts pupil Increases salivation Decreases br eathing r ate Slows heart rate Widens blood vessels Increases digestive activity Increases digestive activity Parasympathetic Nervous System (Cranial andsacral regions of spinalcord) Copyright 2009 Pearson Education, Inc. 9 Contracts bladder muscles Stimulates defecation Synapse between neur ons Figur e 8.12 (1 of 2) Parasympathetic Nervous System PNS Sympathetic Nervous System Sympathetic Nervous System (Thoracic and lumbar regions of spinalcord) Eyes Constricts Salivation Stimulate Heart Rate Slows Breathing Constricts Blood vessels Dilates Digestion Stimulates Bladder Constricts Sex Organs Stimulates Copyright 2009 Pearson Education, Inc. 11 Ganglion Dilates pupil Decreases salivation Increases br eathing r ate Increases heart rate Narrows blood vessels Slows digestive activity Slows digestive activity Relaxes bladder m uscles Inhibits defecation Stimulates secretion of epinephr ine and nor epinephr ine Causes salt and water retention Figur e 8.12 (2 of 2) 3
Sympathetic Nervous System Central Nervous System Eyes Dilates pupils Salivation Inhibits Heart Rate Accelerates Breathing Facilitates Digestion Inhibits Bladder Relaxes Sex Organs Inhibits Stimulates secretion of epinephrine & norepinephrine Stimulates release of free glucose Is protected by 4 different things Bone Skull Vertebral Column Meninges Cerebrospinal Fluid (CSF) Blood-Brain Barrier (BBB) Copyright 2009 Pearson Education, Inc. 13 Copyright 2009 Pearson Education, Inc. 14 Protection of the CNS The bones of the skull and The meninges are three vertebral column are hard membranes that protect cases that protect the brain the brain and spinal cord. and spinal cord. CNS Protection - Meninges Ventricles of the brain 3 layers Dura Mater Arachnoid Mater Pia Mater Cerebrospinal fluid cushions the brain and spinal cord. Figure 8.2 Copyright 2009 Pearson Education, Inc. 16 4
Meningitis Inflammation of the meninges Multiple causes Bacteria, Viruses, Fungi Can lead to encephalitis Inflammation of the brain CNS Protection Cerebrospinal Fluid 3 Functions Shock absorption Support the weight of the brain Nourishment and waste removal Copyright 2009 Pearson Education, Inc. 17 Copyright 2009 Pearson Education, Inc. 18 CNS Protection Blood-brain Barrier Astrocytes - supporting cells for neurons in the CNS - help to form the blood-brain barrier. A functional barrier between the interstitial fluid and the blood Controls entrance of compounds from the blood into the brain ØTight junctions between brain capillary endothelial cells Astrocyte foot processes Copyright 2009 Pearson Education, Inc. 19 5
Review Question The Brain and Spinal Cord What is the inner most layer of the meninges? a) Pia Mater b) Dura Mater c) Arachnoid membrane Copyright 2009 Pearson Education, Inc. 21 Spinal Cord the vital link Extends through the Foramen magnum (from the Medulla oblongata) down the back to the level of the 1 st or 2 nd lumbar vertebrae. Trans mits mes s ages between the brain and the res t of the body Contains neural networks responsible for locomotion 4 different regions Cervical, thoracic, lumbar, sacral Copyright 2009 Pearson Education, Inc. 23 6
Spinal Cord and Spinal Nerves Nerve Nerve vs Neuron A bundle of parallel axons, dendrites, or both from many neurons Usually covered with tough connective tissue These bundles contain Axons Blood vessels Connective tissue Copyright 2009 Pearson Education, Inc. 26 Nerve Connective tissue surrounding one nerve Blood supply Axons within a connective tissue sheath One axon (d)the anatomy of a nerve Copyright 2009 Pearson Education, Inc. 27 Copyright 2009 Pearson Education, Inc. 28 Figure 8.9d 7
Spinal Cord Cross-section of the Spinal Cord Copyright 2009 Pearson Education, Inc. 29 Gray Matter White Matter - mostly cell bodies, dendrites and axon terminals - many synapses between neurons - integration areas of the CNS CNS gray matter areas: gray horns of the spinal cord cortex of the cerebrum and cerebellum nuclei - mostly myelinated axons - conduct action potentials over longer distances - tracts are bundles of axons in the CNS (similar to nerves in the PNS) 8
Neurons in the Central Nervous System Interneurons Located between sensory and motor neurons within the CNS Integrate and interpret sensory signals Copyright 2009 Pearson Education, Inc. 34 Neurons in the Peripheral Nervous System Afferent/Sensory Cell bodies are located in the dorsal root ganglion Efferent/Motor Cell bodies are located in the gray matter of the spinal cord Their axons leave the CNS and go to the skeletal muscles Copyright 2009 Pearson Education, Inc. 35 Copyright 2009 Pearson Education, Inc. 36 9
Copyright 2009 Pearson Education, Inc. 37 Copyright 2009 Pearson Education, Inc. 38 12-5 Review Questions Spinal Nerves Which neuron has their cell body in the dorsal root ganglion? What neuroglial cells provide nutrients to neurons? Name the projections of the neuron cell body that carry messages TO the cell body. Copyright 2009 Pearson Education, Inc. 39 10
Dermatomes Spinal Reflexes Reflex Actions Need a really quick response Ex. Reacting to a hot stove Spinal cord can process the information and send a response back to the motor nerves Pathway Sensory receptor à Sensory neuron à Interneurons à Motor neuron à an effector (muscle) Copyright 2009 Pearson Education, Inc. 43 11
Reflex Arc https://www.youtube.com/watch?v=nkpewao2wg Reflex Arc 1. Sensory Receptor 2. Sensory Neuron 3. Integrating Center 4. Motor Neuron 5. Effector 2) Sensor y Neuron 1) Receptor 3) 4) Motor Neuron 5) Effector Copyright 2009 Pearson Education, Inc. 45 Muscle Spindle Stretch Reflex - a monosynaptic spinal reflex Flexion (Withdrawal) Reflex and Crossed Extensor Reflex - polysynaptic spinal reflexes 12
What are the somatic nervous system and autonomic nervous system, what do they control? What are reflex actions? What are the Parasympathetic division and the Sympathetic division What specifically do they control (increase heart rate, etc) What protects the CNS What are the three layers of the meninges, be able to describe them and their location (which is the inner, middle or outer layer. What is meningitis, what is the cause What are the functions of cerebrospinal fluid What is the function of the blood-brain barrier, what does it allow to pass? What are the functions of the nervous system? What are the 2 types of cells in the nervous tissue? What are the 3 types of neuroglial cells and their functions? What are the 2 main divisions of the nervous system and where is each found? What are the parts and functions of a neuron? What are the 3 types of neurons? Know their functions and where they are located Where are the cell bodies located for motor and sensory nerve cells? Copyright 2009 Pearson Education, Inc. 51 Copyright 2009 Pearson Education, Inc. 52 13
What are Schwann cells and Oligodendrocytes? What is their function? Where are they found? What is the cause and effects of multiple sclerosis? What are the parts of a nerve? How do ions pass through membranes? What is the function of the sodium potassium pump? How many ions are pumped? What are the steps of messages being conducted through a neuron? Starting with the resting stage and ending with the next neuron or muscle being stimulated Copyright 2009 Pearson Education, Inc. 53 Copyright 2009 Pearson Education, Inc. 54 What ions enter and then leave the neuron during depolarization? During repolarization? What is the relative charge of the inside vs the outside of the neuron during these events? What is the order of events? Know the components of the synapse What is the function of neurotransmitters? How do neurotransmitters work? Where do they work? Know the ions involved and their functions Copyright 2009 Pearson Education, Inc. 55 Copyright 2009 Pearson Education, Inc. 56 14
What is acetylcholine? Where is it found? What effect does it have? How is it removed from the synaptic cleft? What is the cause and effect of Myasthenia Gravis? Copyright 2009 Pearson Education, Inc. 57 15