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Medical Terminology

Medical Terminology. Nervous System Chapter 15. Nervous System. Coordinates many activities of the body senses changes in internal and external environment interprets these changes coordinates appropriate response in order to maintain homeostasis

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Medical Terminology

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  1. Medical Terminology Nervous System Chapter 15

  2. Nervous System • Coordinates many activities of the body • senses changes in internal and external environment • interprets these changes • coordinates appropriate response in order to maintain homeostasis • When the brain ceases functioning, the body dies

  3. Structures • nerve is one or more bundles of impulse carrying fibers that connect the brain & spinal cord with body • Nerves carry chemical and electrical signals very quickly, what system carries messages slowly to maintain homeostasis?

  4. Nervous Tissue • Neurons - transmit impulses • Sensory= towards (afferent, ascending) ascending where? • motor = away from (efferent, descending) • Neuroglia - support neurons • Glia= “glue”

  5. Neuron • dendrites- (broccoli) rootlike structures that receive impulses and conduct them to the cell body • cell body - contains nucleus • axon- (asparagus) one stalk that extends away from the cell body and conducts impulses away from the nerve cell

  6. Neuron Anatomy • Myelin sheath - • insulation • accelerates impulse transmission • appears as white covering • myelin on axons in brain and spinal cord gives white appearance • The myelin sheath degenerates in diseases such as multiple sclerosis. So neurological processes are slowed (speech, motor)

  7. Neuron Anatomy • Schwann cell • type of neuroglial cell wrapped around axon • forms the myelin sheath

  8. Neurotransmitters • Synapse- space between two neurons or between a neuron and a receptor organ. • Impulses are passed from one neuron to another at a junction called the synapse. • Electrical current within neuron causes release of chemical substance called a neurotransmitter. AKA electrochemicals

  9. Neurotransmitter diffuses across the synapse to receptor sites on the dendrite of the next neuron. • Generates the next electrical stimulus. • Terminal ends of the axon release a transmitter substance that affects the dendrites of the next neuron. • One way transmission of the impulse is assured because only the axons release these chemicals.

  10. Neuroglia • gli/o or nerve glue • neuroglia or glial cells • astrocytes - blood brain barrier (star) • oligodendrocytes - facilitate myelin development • microglia - phagocytic properties • ependyma - assist in CSF circulation

  11. Divisions • Central Nervous System • brain and spinal cord • Peripheral Nervous System • cranial nerves and spinal nerves • fibers are sensory or motor • Autonomic Nervous System • ganglia on either side of the spinal cord • sympathetic nervous system • parasympathetic nervous system

  12. Brain • Cerebrum • Cerebellum • Brainstem

  13. Cerebrum MOST DISTAL & LARGEST HIGHESTFUNCTIONS SUCH AS MEMORY, EMOTIONS & JUDGEMENT Cerebrum Cerebellum Medulla Oblongata Two hemispheres divided by a fissure (Right side controls left side of body) Lobes: frontal, parietal, temporal, occipital

  14. Lobes of cerebrum • Frontal • motor functions • Parietal • receives & interprets information • Occipital • eyesight • Temporal • hearing & smell

  15. Cerebellum • receives incoming messages regarding movement within joints, muscle tone, and position of the body. • relay these messages to other parts of brain to control skeletal activity • movement, coordination, balance

  16. Thalamus • below the cerebrum • monitors sensory stimuli by suppressing some and magnifying others

  17. Hypothalamus-a regulator • Autonomic Nervous System • emotional responses/behavior • body temperature • food intake= hunger • water balance and thirst • sleep-wake cycles • endocrine system activity

  18. Brainstem “where you live” • stalk-like portion of the brain • midbrain - conduction pathways • pons - nerve cells cross from one side to the other • medulla oblongata - basic life functions • origin for 10 of 12 cranial nerves • controls respiration, blood pressure, heart rate

  19. Spinal Cord • housed within vertebral column • continuos with brain stem • ascending and descending nerve tracts • protected by CSF and meninges • gray matter in internal section - not protected by myelin sheath • myelinated white matter in outer area

  20. Meningescover brain and spinal cord • Dura “hard” mater • Outer layer • arachnoid • Middle layer • subarachnoid space • contains CSF • pia mater/ inner layer • blood vessels and lymph

  21. Bell’s Palsy • Facial paralysis • functional disorder of VII cranial nerve • asthenia • keratitis • dysphasia • Treatment • anti-inflammatory drugs

  22. Cerebrovascular Disease • Arteriosclerosis • Cerebrovascular accident (CVA, apoplexy) • ischemia • transient ischemic attack • aphasia • ataxia • Right CVA affects left side of body RCVA with L hemiparesis

  23. Seizure Disorders • Epilepsies • dysrhythmias in the brain • etiology: brain injury, congenital anomalies, metabolic disorders, brain tumors • Convulsions

  24. Parkinson’s Disease • Progressive neurological disorder • deterioration of portion of brain controlling movement • bradykinesia, hypokinesia, tremors, shuffling gait. • Treatment: l-dopa

  25. Multiple Sclerosis • Progressive degenerative disease of CNS • Inflammation, hardening, and loss of myelin throughout spinal cord and brain • Impeded transmission of electrical impulses • tremors, muscle weakness, slowness of movements • etiology: autoimmune, or slow virus

  26. Alzheimer’s Diseaseorganic disorder • Progressive neurological disorder • plaques develop in cerebral cortex • memory loss, cognitive decline, and personality changes • leading cause of senile dementia • research: some meds prevent breakdown of brain chemicals

  27. Oncology • Intracranial tumors • primary sites • metastatic sites • Signs and Symptoms • headaches • papilledema • personality changes

  28. Agnosia (inability to comprehend sensory imformation) • Asthenia (weakness) • Ataxia (“lack of order” uncoordinated movements”) • cerebral palsy • closed head trauma • coma • concussion • Guillian-Barre syndrome • herpes zoster (shingles)

  29. Huntington’s chorea • hydrocephalus • lethargy • neural tube defect • paraplegia

  30. Paresthesia • poliomyelitis • quadriplegia • Reye’s syndrome • sciatica • syncope • vasovagal • transient ischemic attack (TIA)

  31. Cerebral angiography • echoencephalography • electroencephalography (EEG) • myelography • computed tomography (CT scan)

  32. Surgical and Therapeutic Procedures • Cryosurgery • Spinal puncture, spinal tap, lumbar puncture • Vagotomy/ CNX (resect part of vagal nerve to stop Hydrochloric acid secretion) • Vagal nerve stimulator used to reduce seizure activity in med resistant pts

  33. Pharmacology • analgesics • anticonvulsants • antidepressants • hypnotics • opiates • psychotropic drugs • sedatives • tranquilizers

  34. End Chapter 15 Nervous System

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