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Chapter 27 - The nervous system. The nervous system is a highly complex system. It controls all other organ systems and is important for maintaining balance within those systems. Disorders of the nervous system are numerous and often very difficult to diagnose and treat because of the complexity of this system.
PowerPoint® to accompany Medical Assisting Chapter 27 Second Edition Ramutkowski Booth Pugh Thompson Whicker Copyright © The McGraw-Hill Companies, Inc Permission required for reproduction or display The Nervous System Objectives: 271 Explain the difference between the central nervous system and the peripheral nervous system 272 Describe the functions of the nervous system 273 Describe the structure of a neuron 274 Describe the function of a nerve impulse and how a nerve impulse is created 275 Describe the structure and function of a synapse 276 Describe the function of the bloodbrain barrier The Nervous System Objectives: 277 Describe the structure and functions of meninges 278 Describe the structure and functions of the spinal cord 279 Define reflex and list the parts of a reflex arc 2710 List the major divisions of the brain and give the general functions of each 2711 Describe the differences between the somatic nervous system and autonomic nervous system. The Nervous System Objectives: 2712 Explain the two divisions of the autonomic nervous system 2713 Explain the functions of the cranial and spinal nerves 2714 Describe the location and function of cerebrospinal fluid 2715 Describe various disorders of the nervous system and how they are diagnosed and treated Introduction Nervous system is a highly complex system divided into two major parts; Controls all other organs systems and is important for maintaining balance within those systems Central nervous system (CNS) Peripheral nervous system Disorders of the nervous system are numerous and often very Disorders of the nervous system are numerous and often very difficult to diagnose and treat because of the complexity of difficult to diagnose and treat because of the complexity of this system. this system. General Functions of the Nervous System Detect and interpret sensory information, Make decisions about the sensory information that is received, Carry out motor functions based on the decisions made For example, if you feel For example, if you feel pain, your brain might pain, your brain might decide you need to move decide you need to move away from the painful away from the painful stimulus. stimulus. Neuron Structure Transmit electrochemical messages called nerve impulses to other neurons and effectors (muscles or glands) Neurons lose their ability to divide When destroyed by disease, they cannot be replaced Neuron Structure (cont.) Neurons have cell Neurons Neurons have cell Neurons body processes called body processes called nerve fibers that nerve fibers that extend from the cell extend from the cell body. body. Dendrites short Dendrites function is to receive information (nerve impulses) for the neuron Axons long function Axons is to send information (nerve impulses) away from the cell body Nerve Impulse Nerve impulse is the flow of electric current along the axon membrane At rest, or in its polar state, more sodium (Na+) is on the outside of the membrane, which makes the outside positive and the inside negative When sodium moves into the cell, the membrane depolarizes, which means that the inside becomes more positive. The membrane repolarizes when potassium (K+) and later sodium move to the outside of the cell membrane Synapse Synaptic knobs contact dendrites, cell bodies and the axons of other neurons Synaptic knob is contacting is called a postsynaptic structure. Within synaptic knobs are vesicles or small sacs that contain chemicals called neurotransmitters. When the nerve impulse reaches the synaptic knobs, the neurotransmitters are released onto postsynaptic structures 10 Spinal Nerves Spinal nerves are peripheral nerves that originate Spinal nerves are peripheral nerves that originate from the spinal cord. from the spinal cord. 31 pairs of spinal nerves: 31 pairs of spinal nerves: 8 pairs of cervical nerves (C1 through C8) 8 pairs of cervical nerves (C1 through C8) 12 pairs of thoracic nerves (T1 through T12) 12 pairs of thoracic nerves (T1 through T12) 5 pairs of lumbar nerves (L1 through L5) 5 pairs of lumbar nerves (L1 through L5) 5 pairs of sacral nerves (S1 through S5) 5 pairs of sacral nerves (S1 through S5) One pair of coccygeal nerves (Co) One pair of coccygeal nerves (Co) 37 Somatic and Autonomic Nervous Systems Consists of nerves that connect the CNS to skin and skeletal muscle Somatic nervous system “voluntary” nervous system because it controls skeletal muscles, which are under voluntary control. Autonomic nervous system consists of nerves that connect the CNS to organs and other structures such as the heart, stomach, intestines, glands, blood vessels, and bladder (among others) “involuntary” nervous system. 38 Neurologic Testing Typical neurologic examination: State of consciousness Reflex activity Speech patterns Motor patterns 39 Diagnostic Procedures Common diagnostic procedures Common diagnostic procedures Lumbar Puncture Computerized Magnetic Tomography (CT) Resonance Scan Imaging (MRI). Electroencephalogram Positron Emission (EEG) Tomography X Ray (PET) Scan 40 Reflex Testing Biceps reflex The absence of Biceps reflex Biceps reflex The absence of Biceps reflex this reflex may indicate spinal cord this reflex may indicate spinal cord damage in the cervical region. damage in the cervical region. Knee reflex The absence of this Knee reflex Knee reflex The absence of this Knee reflex reflex may indicate damage to reflex may indicate damage to lumbar or femoral nerves. lumbar or femoral nerves. Abdominal reflexes These Abdominal reflexes Abdominal reflexes These Abdominal reflexes reflexes are used to evaluate reflexes are used to evaluate damage to thoracic spinal nerves damage to thoracic spinal nerves 41 Apply Your Knowledge What is the somatic nervous system? 42 Apply Your Knowledge Answer What is the somatic nervous system? Somatic nervous system (“voluntary”) nervous system because it controls skeletal muscles, which are under voluntary control 43 Diseases and Disorders of the Nervous System Alzheimer's Disease a progressive, Alzheimer's Disease degenerative disease that occurs in the brain. Amyotrophic Lateral Sclerosis (ALS) a Amyotrophic Lateral Sclerosis (ALS) fatal disorder characterized by the degeneration of neurons in the spinal cord and brain Bell's Palsy is a disorder in which facial Bell's Palsy muscles are very weak or totally paralyzed. 44 Diseases and Disorders of the Nervous System (cont.) Brain Tumors and Cancers abnormal Cancers growths in the brain Epilepsy and Seizures occur when parts of the brain receive a burst of electrical signals that disrupt normal brain functioning GuillainBarré Syndrome a disorder Syndrome in which the body's immune system attacks part of the peripheral nervous system. 45 Diseases and Disorders of the Muscular System Multiple Sclerosis (MS) Headaches affect almost Headaches affect almost Multiple Sclerosis (MS) a chronic disease of the everyone at some point in everyone at some point in central nervous system their life their life in which myelin is Tension Headaches Tension Headaches Cluster Cluster Migraine Migraine destroyed Stroke brain cells die due Stroke to an inadequate blood flow. 46 Diseases and Disorders of the Muscular System (cont.) Meningitis is an Meningitis inflammation of the meninges Neuralgias are a Neuralgias group of disorders commonly referred to as nerve pain Parkinson's Disease is a motor Disease system disorder Sciatica occurs Sciatica when the sciatic nerve is damaged 47 Apply Your Knowledge The doctor has told your patient she has had a stroke. How would you explain this to the family? 48 Apply Your Knowledge Answer The doctor has told your patient she has had a stroke. How would you explain this to the family? A stroke happens when brain cells are damaged or die due to an inadequate blood flow. 49 Summary Medical Assistant Functions of the nervous system include detecting and interpreting sensory information, making decisions about that information, and responding to and carrying out motor functions based on those decisions Knowledge of this system is essential when assisting the physician during a neurologic exam 50 End of Chapter 51 ... Objectives: 27 7 Describe the structure and functions of meninges 27 8 Describe the structure and functions of the spinal cord 27 9 Define reflex and list the parts of a reflex arc 27 10 List the major divisions of the brain and give the ... nervous system 27 13 Explain the functions of the cranial and spinal nerves 27 14 Describe the location and function of cerebrospinal fluid 27 15 Describe various disorders of the nervous system and how they are diagnosed and treated... Describe the structure of a neuron 27 4 Describe the function of a nerve impulse and how a nerve impulse is created 27 5 Describe the structure and function of a synapse 27 6 Describe the function of the bloodbrain barrier