1. PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART A 7 The Nervous System

2. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  Sensory input—gathering information  To monitor changes occurring inside and outside the body  Changes = stimuli  Integration  To process and interpret sensory input and decide if action is needed

3. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  Motor output  A response to integrated stimuli  The response activates muscles or glands

4. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System Figure 7.1

5. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of the Nervous System  Central nervous system (CNS)  Brain  Spinal cord  Peripheral nervous system (PNS)  Nerves outside the brain and spinal cord  Spinal nerves  Cranial nerves

6. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Sensory (afferent) division  Nerve fibers that carry information to the central nervous system  Motor (efferent) division  Nerve fibers that carry impulses away from the central nervous system

7. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2

8. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Motor (efferent) division (continued)  Two subdivisions  Somatic nervous system = voluntary  Autonomic nervous system = involuntary

9. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Support cells in the CNS are grouped together as “neuroglia”  Function: to support, insulate, and protect neurons

10. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Astrocytes  Abundant, star-shaped cells  Brace neurons  Form barrier between capillaries and neurons  Control the chemical environment of the brain

11. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3a

12. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Microglia  Spiderlike phagocytes  Dispose of debris

13. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3b

14. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Ependymal cells  Line cavities of the brain and spinal cord  Circulate cerebrospinal fluid

15. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3c

16. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Oligodendrocytes  Wrap around nerve fibers in the central nervous system  Produce myelin sheaths

17. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3d

18. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Satellite cells  Protect neuron cell bodies  Schwann cells  Form myelin sheath in the peripheral nervous system

19. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3e

20. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Neurons = nerve cells  Cells specialized to transmit messages  Major regions of neurons  Cell body—nucleus and metabolic center of the cell  Processes—fibers that extend from the cell body

21. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Cell body  Nissl substance  Specialized rough endoplasmic reticulum  Neurofibrils  Intermediate cytoskeleton  Maintains cell shape

22. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.4

23. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Cell body  Nucleus  Large nucleolus  Processes outside the cell body  Dendrites—conduct impulses toward the cell body  Axons—conduct impulses away from the cell body

24. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.4

25. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Axons end in axonal terminals  Axonal terminals contain vesicles with neurotransmitters  Axonal terminals are separated from the next neuron by a gap  Synaptic cleft—gap between adjacent neurons  Synapse—junction between nerves

26. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Myelin sheath—whitish, fatty material covering axons  Schwann cells—produce myelin sheaths in jelly roll–like fashion  Nodes of Ranvier—gaps in myelin sheath along the axon

27. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.5

28. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Cell Body Location  Most neuron cell bodies are found in the central nervous system  Gray matter—cell bodies and unmyelinated fibers  Nuclei—clusters of cell bodies within the white matter of the central nervous system  Ganglia—collections of cell bodies outside the central nervous system

29. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons  Carry impulses from the sensory receptors to the CNS  Cutaneous sense organs  Proprioceptors—detect stretch or tension  Motor (efferent) neurons  Carry impulses from the central nervous system to viscera, muscles, or glands

30. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons Figure 7.7

31. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Interneurons (association neurons)  Found in neural pathways in the central nervous system  Connect sensory and motor neurons

32. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Classification Figure 7.6

33. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.8a Structural Classification of Neurons  Multipolar neurons—many extensions from the cell body

34. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of Neurons  Bipolar neurons—one axon and one dendrite Figure 7.8b

35. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of Neurons  Unipolar neurons—have a short single process leaving the cell body Figure 7.8c

36. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Properties of Neurons  Irritability  Ability to respond to stimuli  Conductivity  Ability to transmit an impulse

37. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Resting neuron  The plasma membrane at rest is polarized  Fewer positive ions are inside the cell than outside the cell  Depolarization  A stimulus depolarizes the neuron’s membrane  A depolarized membrane allows sodium (Na+) to flow inside the membrane  The exchange of ions initiates an action potential in the neuron

38. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9a–b

39. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Action potential  If the action potential (nerve impulse) starts, it is propagated over the entire axon  Impulses travel faster when fibers have a myelin sheath

40. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9c–d

41. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Repolarization  Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane  The sodium-potassium pump, using ATP, restores the original configuration

42. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9e–f

43. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses  Impulses are able to cross the synapse to another nerve  Neurotransmitter is released from a nerve’s axon terminal  The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter  An action potential is started in the dendrite

44. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes

45. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 1 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron

46. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 2 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Vesicle fuses with plasma membrane Synaptic cleft Ion channels Receiving neuron Transmitting neuron

47. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 3 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron

48. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 4 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron

49. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 5 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Ion channel opens

50. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 6 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes

51. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 7 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes

52. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc  Reflex—rapid, predictable, and involuntary response to a stimulus  Occurs over pathways called reflex arcs  Reflex arc—direct route from a sensory neuron, to an interneuron, to an effector

53. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a Stimulus at distal end of neuron Skin Spinal cord (in cross section) Interneuron Receptor Effector Sensory neuron Motor neuron Integration center (a)

54. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a, step 1 Stimulus at distal end of neuron Skin Receptor (a)

55. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a, step 2 Stimulus at distal end of neuron Skin Receptor Sensory neuron (a)

56. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a, step 3 Stimulus at distal end of neuron Skin Spinal cord (in cross section) Interneuron Receptor Sensory neuron Integration center (a)

57. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a, step 4 Stimulus at distal end of neuron Skin Spinal cord (in cross section) Interneuron Receptor Sensory neuron Motor neuron Integration center (a)

58. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reflex Arc Figure 7.11a, step 5 Stimulus at distal end of neuron Skin Spinal cord (in cross section) Interneuron Receptor Effector Sensory neuron Motor neuron Integration center (a)

59. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b–c Spinal cord Sensory (afferent) neuron Inter- neuron Motor (efferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) Effector (quadriceps muscle of thigh) Effector (biceps brachii muscle) Synapse in ventral horn gray matter (c) (b)

60. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b, step 1 Spinal cord Sensory receptors (stretch receptors in the quadriceps muscle) (b)

61. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b, step 2 Spinal cord Sensory (afferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) (b)

62. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b, step 3 Spinal cord Sensory (afferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) Synapse in ventral horn gray matter (b)

63. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b, step 4 Spinal cord Sensory (afferent) neuron Motor (efferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) Synapse in ventral horn gray matter (b)

64. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b, step 5 Spinal cord Sensory (afferent) neuron Motor (efferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) Effector (quadriceps muscle of thigh) Synapse in ventral horn gray matter (b)

65. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11c, step 1 Spinal cord Sensory receptors (pain receptors in the skin) (c)

66. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11c, step 2 Spinal cord Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) (c)

67. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11c, step 3 Spinal cord Inter- neuron Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) (c)

68. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11c, step 4a Spinal cord Inter- neuron Motor (efferent) neuron Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) (c)

69. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11c, step 4b Spinal cord Inter- neuron Motor (efferent) neuron Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) Effector (biceps brachii muscle) (c)

70. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Simple Reflex Arc Figure 7.11b–c Spinal cord Sensory (afferent) neuron Inter- neuron Motor (efferent) neuron Sensory receptors (stretch receptors in the quadriceps muscle) Sensory (afferent) neuron Sensory receptors (pain receptors in the skin) Effector (quadriceps muscle of thigh) Effector (biceps brachii muscle) Synapse in ventral horn gray matter (c) (b)

71. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Types of Reflexes and Regulation  Somatic reflexes  Activation of skeletal muscles  Example : When you move your hand away from a hot stove

72. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Types of Reflexes and Regulation  Autonomic reflexes  Smooth muscle regulation  Heart and blood pressure regulation  Regulation of glands  Digestive system regulation

73. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Types of Reflexes and Regulation  Patellar, or knee-jerk, reflex is an example of a two-neuron reflex arc Figure 7.11d

74. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Central Nervous System (CNS)  CNS develops from the embryonic neural tube  The neural tube becomes the brain and spinal cord  The opening of the neural tube becomes the ventricles  Four chambers within the brain  Filled with cerebrospinal fluid

75. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Central Nervous System (CNS) Figure 7.12a

76. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain  Cerebral hemispheres (cerebrum)  Diencephalon  Brain stem  Cerebellum

77. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.12b

78. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Cerebral Hemispheres (Cerebrum)  Paired (left and right) superior parts of the brain  Includes more than half of the brain mass  The surface is made of ridges (gyri) and grooves (sulci)

79. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13a

80. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Lobes of the cerebrum  Fissures (deep grooves) divide the cerebrum into lobes  Surface lobes of the cerebrum  Frontal lobe  Parietal lobe  Occipital lobe  Temporal lobe

81. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13b

82. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Specialized areas of the cerebrum  Primary somatic sensory area  Receives impulses from the body’s sensory receptors  Located in parietal lobe  Primary motor area  Sends impulses to skeletal muscles  Located in frontal lobe  Broca’s area  Involved in our ability to speak

83. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13c

84. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.14

85. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Cerebral areas involved in special senses  Gustatory area (taste)  Visual area  Auditory area  Olfactory area

86. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Interpretation areas of the cerebrum  Speech/language region  Language comprehension region  General interpretation area

87. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13c

88. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Layers of the cerebrum  Gray matter—outer layer in the cerebral cortex composed mostly of neuron cell bodies  White matter—fiber tracts deep to the gray matter  Corpus callosum connects hemispheres  Basal nuclei—islands of gray matter buried within the white matter

89. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.15

90. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.16

91. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Sits on top of the brain stem  Enclosed by the cerebral hemispheres  Made of three parts  Thalamus  Hypothalamus  Epithalamus

92. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.12b

93. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.16a

94. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.16b

95. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Thalamus  Surrounds the third ventricle  The relay station for sensory impulses  Transfers impulses to the correct part of the cortex for localization and interpretation

96. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Hypothalamus  Under the thalamus  Important autonomic nervous system center  Helps regulate body temperature  Controls water balance  Regulates metabolism

97. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Hypothalamus (continued)  An important part of the limbic system (emotions)  The pituitary gland is attached to the hypothalamus

98. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Epithalamus  Forms the roof of the third ventricle  Houses the pineal body (an endocrine gland)  Includes the choroid plexus—forms cerebrospinal fluid

99. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Attaches to the spinal cord  Parts of the brain stem  Midbrain  Pons  Medulla oblongata

100. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem Figure 7.16a

101. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Midbrain  Mostly composed of tracts of nerve fibers  Has two bulging fiber tracts— cerebral peduncles  Has four rounded protrusions— corpora quadrigemina  Reflex centers for vision and hearing

102. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Pons  The bulging center part of the brain stem  Mostly composed of fiber tracts  Includes nuclei involved in the control of breathing

103. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Medulla Oblongata  The lowest part of the brain stem  Merges into the spinal cord  Includes important fiber tracts  Contains important control centers  Heart rate control  Blood pressure regulation  Breathing  Swallowing  Vomiting

104. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Reticular Formation  Diffuse mass of gray matter along the brain stem  Involved in motor control of visceral organs  Reticular activating system (RAS) plays a role in awake/sleep cycles and consciousness

105. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Reticular Formation of the Brain Stem Figure 7.16b

106. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebellum  Two hemispheres with convoluted surfaces  Provides involuntary coordination of body movements

107. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebellum Figure 7.16a