1. ELAINE N. MARIEB EIGHTH EDITION 7 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY PART A The Nervous System

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings I. Introduction: 1) The nervous system is the master controlling and communicating system of the body. 2) Every thought, action and emotion is controlled by it. 3) To carry out its normal role there are 3 overlapping functions

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings a) Sensory: Information going toward CNS b) Integration: making decision about the input c) Motor: reaction going from CNS

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings II. Organization of the system 1) To simplify the study, the system is divided by structure and function, but act as a coordinated unit 2) Structural classification: Central (CNS) and Peripheral (PNS): 3) Functional classification: a) Sensory (afferent): 1. Somatic: body structures 2. Visceral: internal organs

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings b) Motor (efferent): 1. Somatic nervous: voluntarily control of skeletal muscles 2. Autonomic (ANS): regulates events that are automatic

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings III. Nervous Tissue 1) Supporting cells a) Neuroglia: general term for all supporting cells in the CNS b) Astrocytes: star-shaped, 1/5 of the neural tissue, braces and anchors neurons to capillaries and regulate materials coming from the blood c) Microglia: Spider-like phagocytes that dispose of debris

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings d) Ependymal: line the cavities of the brain and spinal cord, helps circulate CSF e) Oligodendrocytes: Produces myelin in the CNS f) Schwann cells: form myelin sheaths in the nerve fibers g) Satellite cells: protect and cushion

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

9. 2) Neuron Anatomy: a) Neuron: the nerve cell, specialized to transmit impulses b) Parts (fig 7.4): Consists of 1.Dendrite: carry impulse toward the body 2. Body: carry out normal celprocesses 3. Axon: carry impulses from the body 4. Axon terminal: branching of the axon’s end and release neurotransmitters

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Anatomy Figure 7.4a–b

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.10

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings c) Synapse (synaptic cleft): d) Neurotransmitter: e) Myelin: f) Neurilemma: 1.Formed by part of the Schwann cell external to the myelin sheath 2. Plays an important role in fiber regeneration

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings g) Nodes of Ranvier: indentions in the myelin sheath

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3) Terms: a) Nuclei: Cluster of nerve cell bodies in the CNS b) Ganglion: Cluster of nerve cell bodies outside the CNS c) Tract: bundle of nerve fibers in the CNS d) Nerve: bundle of nerve fibers outside the CNS

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings e) White matter: Dense collections of myelinated fibers f) Gray matter: consists of unmyelinated fibers and bodies 4) Neuron Classification a) Sensory (afferent): b) Motor (Efferent): c) Interneuron (association): connects the sensory and motor neurons

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings d) Multipolar: have several extensions from the cell body e) Bipolar: have 1 axon and 1 dendrite (rare in adults) f) Unipolar: have a single axon only

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 5) Neuron physiology a) Major functions: 1. Irritability: ability to respond to a stimulus and convert it to an impulse 2. Conductivity: ability to transmit an impulse b) Impulse: 1. Polarized: resting neuron with fewer positive ions inside the neuron (K inside and Na outside)

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 2. Depolarization: Stimulation causes Na channels open allowing Na to enter 3. Impulse: The depolarization continues down the axon 4. Repolarization: Sodium-Potassium pump removes the sodium from the cell to the original state c) Saltatory conduction: In myelinated axons, the impulses jump from node to node

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulse Figure 7.9a–c

21. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 6) Reflex: a)Rapid predictable, involuntary response to stimuli b) Reflex arc: pathway carrying the reflex c) Parts: receptor, sensory neuron, interneuron, motor neuron and effector d) Reflex testing is important in evaluating the condition of the nervous system. Any change can indicate a problem and often occur before a pathological condition becomes obvious

22. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a

23. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b–c

24. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings IV. Central Nervous System (CNS) 1) Brain: Two fistfuls of pinkish gray tissue, with the texture of cold oatmeal weighing about 3 lbs 2) Cerebrum: a) Divided into 2 hemispheres b) The most complex part of the brain c) Surface has gyrus, sulcus, fissures and lobes

25. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain Figure 7.12b

26. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cerebral Hemispheres (Cerebrum) Figure 7.13a

27. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3) Cerebral Cortex: a) The outer layer of gray matter, controls speech, memory, logical and emotional response, consciousness, voluntary movement b) Parietal lobe 1. Somatic sensory area 2. Central sulcus: area interpreting body sensations, upside down from body c) Occipital lobe: Vision

28. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings d) Temporal lobe: Auditory & memory e) Frontal lobe: conscious control of skeletal muscles, intellectual reasoning and socially acceptable behavior f) Speech is at the junction of the temporal, parietal and occipital lobes

29. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sensory and Motor Areas of the Cerebral Cortex Figure 7.14

30. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lobes of the Cerebrum Figure 7.15a

31. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 4) Broca’s: gives ability to say words 5) Corpus callosum: connects the two hemispheres 6) Basal nuclei: deep gray matter in the cerebrum that helps regulate voluntary motor activities 7) Diencephalon: a) On top of the brainstem, divided into the thalamus, hypothalamus, and epithalamus

32. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings b) Thalamus: relay station for sensory impulses going to the sensory cortex c) Hypothalamus: important autonomic center, regulates body temperature, water balance, metabolism and center for drives and emotions d) Epithalamus: Consists of pineal body (endocrine system) and choroids plexus (forms CSF)

33. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diencephalon Figure 7.15

34. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 8) Brain Stem: a) Continuous with the spinal cord, consists of midbrain, pons and medulla oblongata b) Midbrain: reflex center involved in vision and hearing c) Pons: Mostly fiber tracts, also controls breathing

35. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings d) Medulla Oblongata: regulate vital visceral activities, heart rate, blood pressure, breathing, swallowing and vomiting e) Reticular formation: motor control of the visceral organs, role in consciousness and sleep cycles (damage causes coma) 9) Cerebellum:

36. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Brain Stem Figure 7.15a

37. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cerebellum Figure 7.15a

38. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings a) Cauliflower shaped structure at base of the brain b) Controls skeletal muscle timing and controls our balance and equilibrium 10) Protection: a)Meninges: 1. Dura mater: tough outer layer 2. Arachnoid: Web-like layer containing CSF 3. Pia mater: inner layer connecting directly to the CNS

39. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protection of the Central Nervous System  Scalp and skin  Skull and vertebral column  Meninges Figure 7.16a

40. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings b) Cerebrospinal fluid (CSF) 1. Watery fluid similar to blood plasma 2. Function to cushion the CNS from trauma 3. Continually produced and drained

41. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ventricles and Location of the Cerebrospinal Fluid Figure 7.17c

42. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings c) Blood-brain barrier: Composed of the least permeable capillaries to keep out harmful substances, unless they are fat- soluble 11) Spinal Cord: a) Carries impulses between brain & body b) About 17 inches long, ends at the L-2 c) Cauda equina: nerves that continue from the end of the spinal cord (horse’s tail)

43. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Spinal Cord Figure 7.18