1. The Brain and Cranial Nerves

2. Major Parts of the Brain 1.Brain stem – continuous with spinal cord  Midbrain  Pons  Medulla Oblongota

4. Major Parts of the Brain 2.Cerebellum – Posterior to brain stem

6. Major Parts of the Brain 3. Diencephalon – superior to the brain stem  Thalamus  Epithalamus  Hypothalamus  Subthalamus

8. Major Parts of the Brain 4. Cerebrum – largest part of the brain supported by the diencephalon and brain stem

10. Brain Stem 1.Medulla Oblongata Continuous with spinal cord Continuous with spinal cord Contains both motor and sensory tracts Contains both motor and sensory tracts

12. Brain Stem / Medulla Contains portrusions of white matter called called pyramids Contains portrusions of white matter called called pyramids

13. Brain Stem / Medulla The crossing of pyramids result in neurons in the left cerebral cortex controlling skeletal muscles on the right side of the body and neurons in the right cerebral cortex controlling skeletal muscles on the left side The crossing of pyramids result in neurons in the left cerebral cortex controlling skeletal muscles on the right side of the body and neurons in the right cerebral cortex controlling skeletal muscles on the left side

14. Brain Stem / Medulla There are reflex centers for regulation of heart rate, respiratory rate, vasoconstriction, swallowing, vomiting There are reflex centers for regulation of heart rate, respiratory rate, vasoconstriction, swallowing, vomiting

15. Brain Stem / Pons  Superior to the medulla  Helps control breathing  It relays nerve impulses related to voluntary skeletal movements from the cerebral cortex to the cerebellum

17. Brain Stem / Midbrain  Extends from the pons to the diencephalon  Cerebral Peduncles, superior colliculi, and inferior colliculi located here

19. Brain Stem / Midbrain  Cerebral Peduncles – contain major motor tracts

20. Brain Stem / Midbrain  Superior colliculi – help with reflex head turning in response to visual stimuli  Responsible for the pupillary reflex and accomodation reflex (adjusts shape of lens for far versus close vision)

21. Brain Stem / Midbrain  Inferior coliculi – helps with reflex head turning in response to auditory stimuli  Reflex center for startle reflex

22. Cerebellum Cerebellum  Vermis - central constricted area  Cerebellar hemispheres – lateral lobes

24. Cerebellum  Cerebellar cortex – superficial layer of the cerebellum made up of gray matter

25. Cerebellum  Arbor Vitae – Deep to the gray mater made up of tracts (White Matter)

27. Cerebellum  Main function – Regulates posture and balance

28. Diencephalon / Thalamus  A pair of oval masses of grey matter, organized into nuclei, with interspersed tracts of white matter

30. Diencephalon / Thalamus  Intermediate mass – Joins the right and left halves of the thalamus

31. Diencephalon / Thalamus  Surrounds the third ventricle

32. Diencephalon / Thalamus  It registers conscious recognition of pain, temp., light touch, and pressure.  You need your cerebral cortex to understand the nature of the pain.

33. Diencephalon / Hypothalamus  Inferior to the thalamus

35. Diencephalon / Hypothalamus  Mammillary bodies – serve as reflexes related to the sense of smell

36. Diencephalon / Hypothalamus  Infundibulum – Connects the pituitary gland to the hypothalamus

37. Diencephalon / Hypothalamus  Axons from the paraventricular and supraoptic nuclei form the hypothalamohypophyseal tract extends through the infundibulum to the posterior pituitary

38. Diencephalon / Hypothalamus  Functions Control of the ANS Control of the ANS Production of hormones Production of hormones Regulation of emotional and behavioral patterns Regulation of emotional and behavioral patterns Regulation of eating and drinking Regulation of eating and drinking Control of body temperature Control of body temperature

39. Diencephalon / Epithalamus  Superior and posterior to thalamus

41. Diencephalon / Epithalamus  Pineal Gland – It secretes the hormone melatonin.

42. Diencephalon / Subthalamus  Below the thalamus  Helps control body movements

44. Circumventricular Organs  Part of the diencephalon called CVOs that can monitor chemical changes in the blood because they lack a blood-brain barrier

45. Circumventricular Organs  Part of the hypothalamus, the pineal gland, and the pituitary gland

47. Circumventricular Organs  Thought to be the site of entry into the brain of HIV.

48. Cerebrum  Largest part of the brain

50. Cerebrum  Cerebral cortex is composed of grey matter  The deep grooves are called fissures  Shallower grooves are called sulci

53. Cerebrum  Beneath the cortex lies cerebral white matter

55. Cerebrum  Longitudinal fissure separates it into right and left halves

56. Cerebrum  The corpus callosum (a bundle of white fibers) connects it internally.

58. Cerebrum  Each cerebral hemisphere is separated into four lobes (frontal, parietal, temporal, and occipital)

60. Cerebrum  White matter is under the cortex and consists of myelinated axons running in three principle directions

61. Cerebrum  Association fibers connect and transmit nerve impulses between gyri in the same hemisphere

62. Cerebrum  Commissural fibers connect gyri in one cerebral hemisphere to the corresponding gyri in the opposite hemisphere

63. Cerebrum  Projection fibers transmit impulses from the cerebrum to other parts of the brain and spinal cord

64. Cerebrum  Basal ganglia are paired masses of grey matter internally located in each cerebral hemisphere

66. Cerebrum  The Basal Ganglia function in controlling muscular movements

67. Cerebrum  Huntington’s disease is a hereditary degenerative disorder of the basal nuclei.  Patients may suffer from abrubt, jerky, almost continuous movements called chorea

68. Cerebrum  Limbic System found in the cerebral hemispheres and diencephalon

70. Cerebrum  It functions in emotional aspects of behavior and memory, and is associated with pleasure and pain  We tend to remember things associated with strong emotions. (Think back to the events you remember from early childhood. What emotions pop up?)

71. Lobes of the Cerebrum  Central Sulcus – Separates the frontal lobe from the parietal lobe

72. Lobes of the Cerebrum  Precentral gyrus – immediately anterior to the central sulcus

73. Lobes of the Cerebrum  Postcentral gyrus – Located immediately posterior to the central sulcus

74. Lobes of the Cerebrum  Lateral cerebral sulcus – Separates the frontal lobe from the temporal lobe

75. Parieto-occipital sulcus  Separates the parietal lobe from the occipital lobe

76. Blood-Brain Barrier (BBB)  Prevents passage of many substances from blood into brain tissue

77. Blood-Brain Barrier (BBB)  Endothelial cells of brain capillaries are sealed together by tight junctions

78. Blood-Brain Barrier (BBB)  Processes of astrocytes press up against the brain capillaries and only allow certain substances to pass from the blood to neurons

79. Blood-Brain Barrier (BBB)  Glucose (water soluble) crosses the BBB via active transport

80. Blood-Brain Barrier (BBB)  Other water soluble substances such as creatinine, urea, and most ions cross slowly

81. Blood-Brain Barrier (BBB)  Proteins and antibiotics cannot cross

82. Blood-Brain Barrier (BBB)  Lipid soluble substances such as oxygen, carbon dioxide, alcohol, and most anesthetic agents cross easily

83. Protective coverings of the Brain 1.Cranium 2.Cranial Meninges – continuous with the spinal meninges

84. Protective coverings of the Brain Cranial Meninges made up of; Dura Mater – outer Dura Mater – outer Arachnoid Mater – middle Arachnoid Mater – middle Pia Mater – inner Pia Mater – inner

85. Protective coverings of the Brain  Subarachnoid space – between the arachnoid mater and pia mater which contains cerebrospinal fluid

86. Protective coverings of the Brain  Three extensions of the dura mater separate parts of the brain

87. Protective coverings of the Brain 1.Falx Cerebri – Separates the two hemispheres

88. Protective coverings of the Brain 2. Falx Cerebelli – Separates the two hemispheres of the cerebellum

89. Protective coverings of the Brain 3. Tentorium Cerebelli – Separates the cerebrum from the cerebellum

90. Cerebrospinal Fluid  Clear colorless liquid

91. Cerebrospinal Fluid  Protects the brain and spinal cord against physical and chemical injuries

92. Cerebrospinal Fluid  Caries glucose, oxygen, and other chemicals from blood to neurons and neuroglia

93. Cerebrospinal Fluid  Circulates through cavities in the brain and spinal cord and in the subarachnoid space of the brain and spinal cord

94. CSF-filled cavities within Brain 1. Lateral Ventricles – Within each hemisphere of the cerebrum

96. CSF-filled cavities within Brain 2. Third Ventricle – A narrow cavity along the midline superior to the hypothalamus and between the R. and L. halves of the thalamus

98. CSF-filled cavities within Brain 3. Fourth Ventricle – between the brain stem and the cerebellum

100. Circulation of CSF  CSF is formed by filtration from networks of capillaries called choroid plexuses (found in the ventricles) and in the brain tissue

102. Circulation of CSF  It circulates through the; 1.Lateral ventricles 2.Third ventricle 3.Cerebral aqueduct 4.Fourth ventricle 5.Then down through the central canal and around the brain (subarachnoid space)

103. Circulation of CSF  Most of the fluid is absorbed by the arachnoid villi

104. Sensory Areas  Sensory Areas of the cerebral cortex are concerned with the reception and interpretation of sensory impulses

105. Sensory Areas  Primary Somatosensory area – located in the postcentral gyrus

106. Sensory Areas  Primary Somatosensory Area – Localizes exactly the points of the body where sensations originate

107. Sensory Areas  Primary Visual Area – located in the occipital lobe and receives impulses that convey information for vision

108. Sensory Areas  Primary Auditory Area – located in the superior part of the temporal lobe

109. Sensory Areas  Primary Auditory Area – Helps you interpret pitch, rhythm, and loudness of speech

110. Sensory Areas  The primary gustatory area – it receives impulses for taste and is located in the parietal lobe

111. Sensory Areas  Primary Olfactory Area – Located in the medial aspect of the temporal lobe and receives impulses for smell

112. Motor Areas  Govern muscular movements

113. Motor Areas  Primary Motor Area – is in the precentral gyrus

114. Motor Areas  Primary Motor Area - It has cell bodies of neurons that descend to the cord

115. Motor Areas  Broca’s Area – Is located in the frontal lobe close to the lateral cerebral sulcus and is the motor speech area

116. Association Areas  Association areas are concerned with complex integrative functions such as memory, emotions, reasoning, will, judgement, personality traits, and intelligence

117. Association Areas  Wernicke’s Area – Is a broad region in the temporal and parietal lobes

118. Association Areas  Wernicke’s Area – Responsible for understanding language, but it may be more involved in sounding out unfamiliar words.

119. Aphasia  Aphasia is the inability to use or comprehend words due to injury to the association or motor speech areas

120. Aphasia  Receptive Aphasia – You have problems with comprehension but your own language is ok

121. Aphasia  Expressive Aphasia – You may comprehend language but your speech does not make any sense

122. Cranial Nerves  Twelve pairs of cranial nerves originate from the brain

123. Cranial Nerves  Some cranial nerves (I, II, VIII) contain only sensory fibers and are called sensory nerves

124. Cranial Nerves  The rest are mixed nerves because they contain both sensory and motor fibers