Nervous System

1. Nervous System ST110 Concorde Career College, Portland

3. Objectives Define the term nerve. Identify the divisions of the nervous system. Describe the functions of the nervous system.

4. Objectives List and identify the structures of the nervous system and describe the function of each. Identify the types of nervous tissue. Understand the physiology of a nerve impulse.

5. Objectives Describe the mechanism by which the nervous system helps to maintain homeostasis. Describe common diseases, disorders, and conditions of the nervous system including signs and symptoms, diagnosis, and available treatment options.

6. Objectives Demonstrate knowledge of medical terminology related to the nervous system verbally and in the written form.

7. Nerve A nerve is a bundle or a group of bundles of nerve fibers outside the central nervous system which connects the brain and spinal cord with the various parts of the body.

8. Divisions of the Nervous System

9. Central Nervous System Brain and spinal cord Control center for the whole system All body sensations and changes in the environment are relayed to the CNS All responses are generated by the CNS

10. Structure

11. Peripheral Nervous System • All the nerves that connect the brain and spinal cord with sensory receptors, muscles and glands • Afferent or sensory neurons • Convey information from the outside of the nervous system to the brain and spinal cord • Efferent or motor neurons • Convey information from the brain and spinal cord to muscles, organs, and glands

12. Peripheral Nerves

13. Spinal Nerves

16. Cranial Nerves • 12 pairs • Need to know • Name • Number • Function • Type (sensory, motor, or mixed)

17. Cranial Nerves First (I) Cranial Nerve Olfactory • Sensory • Carries smell impulses from receptors in the nasal mucosa to the brain

18. Cranial Nerves Second (II) Cranial Nerve Optic • Sensory • Carries visual impulses from the eye to the brain

19. Cranial Nerves Third (III) Cranial Nerve Oculomotor • Mostly motor; partly sensory • Movement of the eyeball, eyelid, and pupil constriction (motor) • Proprioception (sensory)

20. Cranial Nerves Fourth (IV) Cranial Nerve Trochlear • Mostly motor; partly sensory • Movement of the eyeball - superior oblique (motor) • Proprioception (sensory)

21. Cranial Nerves Fifth (V) Cranial Nerve Trigeminal • Mixed • Three divisions 1. Ophthalmic - Skin sensation above the orbit (sensory) 2. Maxillary - Skin sensation from orbit to mouth (sensory) 3. Mandibular - Sensation of the anterior tongue, lower teeth, and cheek (sensory) and chewing (motor)

22. Cranial Nerves Sixth (VI) Cranial Nerve Abducens • Mostly motor; partly sensory • Movement of the eyeball - lateral rectus (motor) • Proprioception (sensory)

23. Cranial Nerves Seventh (VII) Cranial Nerve Facial • Mixed • Proprioception and taste (sensory) • Facial expression, tear and saliva production (motor)

24. Cranial Nerves Eighth (VIII) Cranial Nerve Vestibulocochlear • Sensory • Hearing and balance • Also known as the auditory or acoustic nerve

25. Cranial Nerves Ninth (IX) Cranial Nerve Glossopharyngeal • Mixed • Blood pressure regulation, taste, proprioception (sensory) • Saliva production (motor)

26. Cranial Nerves Tenth (X) Cranial Nerve Vagus • Mixed • Visceral sensation and proprioception (sensory) • Smooth muscle contraction/relaxation and production of digestive fluids • Longest cranial nerve “wanderer”

27. Cranial Nerves Eleventh (XI) Cranial Nerve (Spinal) Accessory • Mostly motor; partly sensory • Proprioception (sensory) • Swallowing and movement of the head and neck (motor)

28. Cranial Nerves Twelfth (XII) Cranial Nerve Hypoglossal • Mostly motor; partly sensory • Proprioception (sensory) • Movement of the tongue (motor)

29. Cranial Nerves

30. Cranial Nerves

31. Cranial Nerve Activity http://www.wisc-online.com/objects/ViewObject.aspx?ID=NUR5104 http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP11504

32. Mnemonics "On Old Olympic Towering Top A Famous Vocal German Viewed Some Hops" OLd OPie OCCasionally TRies TRIgonometry And Feels VEry GLoomy, VAGUe And HYPOactive On, On, On, They Traveled And Found Voldemort Guarding Very Ancient/(Secret) Horcruxes OLd OPrah's OCcupation: TROpical TRIps ABoard FAmous VESsels, GLamorous VAcations, ACCumulating HYPe On Occasion Our Trusty Truck Acts Funny. Very Good Vehicle Any How Obviously Once One Takes The Anatomy Final, Very Good Vodka Alleviates Heartache

33. Somatic (Voluntary) Nervous System Conducts impulses from the brain and spinal cord to skeletal muscle Sensory and motor neurons

34. Autonomic (Involuntary) Nervous System ANS • Internal organ control via glands, smooth and cardiac muscle • Maintenance of HB rate, breathing, blood flow • Sympathetic • Parasympathetic

35. Autonomic (Involuntary) Nervous System • Conducts impulses from the brain and spinal cord to smooth and cardiac muscle tissue • Involuntary • Sympathetic Division (emergency situations, stress, emotions) • Stimulates or speeds up activity • Epinephrine/norepinephrine • Parasympathetic Division • Slows down many activities • Adrenocortical hormone (ACH)

36. Functions of the Nervous System The nervous system acts as the “Control Center” by directing functions of the body’s organs. 1. Receive stimuli (internal or external) 2. Interpret stimuli 3. Reacts to stimuli

37. Neurons Nerve Cells or Neurons • Functional cells of the nervous system • Transmit information via impulses • Dendrites conduct impulses to the cell body • Axons conduct impulses away from the cell body • Nerve • Bundle (fascicle) of nerve cells

38. Structure • Cytoplasmicextentions - • Dendrite: • receives information • Cells may have several, one or none • Typically short and branched • Axon: • Transmits impulses away • Cell has only one • Long • Surrounded by a thin wrapping of fiberous connective tissue called endoneurium • Branch at their ends – Axon Terminals • Make contact with dendrites of other neurons

39. Know all parts

40. Neurons

41. Neurons Neuron Classification • Multipolar • Several dendrites and one axon • Schwann cells (neurolemmocytes) surround the axon to form myelin sheath • Nodes of Ranvier • Bipolar Neurons • One dendrite and one axon • Unipolar Neurons • Axon extends directly from the cell body

43. Neuron Classification • Sensory (afferent) neurons • Receive first impulses from receptors • Unipolar • Impulse is conducted toward brain or spinal cord • Internuncial (association) neurons • Multipolar • Brain and spinal cord • Transmit impulses to appropriate area

44. Neuron Classification • Motor (efferent) • Final nerve cell • Multipolar • Impulse is conducted away from brain or spinal cord • Brings reaction to stimulus

45. Myelin Sheath • Myelin= A soft, white, fatty material wrapped around the membrane of Schwann cells, the substance of the myelin sheath. • Neurilemma=outer cover • Insulating material that covers axon of neuron • Similar to plastic around electrical wire • Gives nerves there white appearance • Made up of Schwann Cells (neurolemmocytes) • Nodes of Ranvier: Gaps on myelin sheath • Gaps allow substances (needed for energy) to flow from extracellular fluid to axons • Capable of regeneration. Not found in brain or spinal cord.

47. Myelin

48. Neuroglial Cells • Insulate, support, and protect neurons • Do not conduct nerve impulses • Schwann Cells • Astrocytes: • Star shaped • Glial cells that attach to small blood vessels to form the BBB • Oligodendrocytes: • Support • Produce fatty sheath of myelin that protects many neurons of the central nervous system • Microglial cells: • Protect neurons (phagocytosis) • Ependymal Cells: • Line ventricles and produce CSF

50. Glial Cells