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The Brain, Cranial Nerves, and Sensory and Motor Pathways

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The Brain, Cranial Nerves, and Sensory and Motor Pathways 13 The Brain, Cranial Nerves, and Sensory and Motor Pathways Lecture Presentation by Lori Garrett © 2018 Pearson Education, Inc. Note to the Instructor: For the third edition of Visual Anatomy & Physiology, we have updated our PowerPoints to fully integrate text and art. The pedagogy now more closely matches that of the textbook. The goal of this revised formatting is to help your students learn from the art more effectively. However, you will notice that the labels on the embedded PowerPoint art are not editable. You can easily import editable art by doing the following: Copying slides from one slide set into another You can easily copy the Label Edit art into the Lecture Presentations by using either the PowerPoint Slide Finder dialog box or Slide Sorter view. Using the Slide Finder dialog box allows you to explicitly retain the source formatting of the slides you insert. Using the Slide Finder dialog box in PowerPoint: 1. Open the original slide set in PowerPoint. 2. On the Slides tab in Normal view, click the slide thumbnail that you want the copied slides to follow. 3. On the toolbar at the top of the window, click the drop down arrow on the New Slide tab. Select Reuse Slides. 4. Click Browse to look for the file; in the Browse dialog box, select the file, and then click Open. 5. If you want the new slides to keep their current formatting, in the Slide Finder dialog box, select the Keep source formatting checkbox. When this checkbox is cleared, the copied slides assume the formatting of the slide they are inserted after. 6. To insert selected slides: Click the slides you want to insert. Slides will place immediately after the slide you have selected in the Slides tab in Normal view. © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of the Brain and Cranial Nerves Learning Outcomes 13.1 Describe the origins of the different regions of the brain from the embryonic neural tube. 13.2 Name the four major regions of the brain, and describe their functions. 13.3 Explain how the brain is protected and supported and how cerebrospinal fluid forms and circulates. 13.4 List the main components of the medulla oblongata, and specify their functions. © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of the Brain and Cranial Nerves Learning Outcomes (continued) 13.5 List the main components of the pons, and specify their functions. 13.6 List the main components of the cerebellum, and specify the functions of each. 13.7 List the main components of the midbrain, and specify the functions of each. 13.8 List the main components of the diencephalon, and specify the functions of each. © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of the Brain and Cranial Nerves Learning Outcomes (continued) 13.9 Identify the main components of the limbic system, and specify the locations and functions of each. 13.10 Describe the structure and function of the basal nuclei of the cerebrum. 13.11 Identify the major superficial landmarks of the cerebrum, and cite the location of each. © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of the Brain and Cranial Nerves Learning Outcomes (continued) 13.12 Identify the locations of the motor, sensory, and association areas of the cerebral cortex, and discuss the functions of each. 13.13 Discuss the significance of the white matter of the cerebral hemispheres. 13.14 Clinical Module: Discuss the origin and significance of the major categories of brain waves seen in an electroencephalogram (EEG). 13.15 Identify the cranial nerves by name and number, and cite the functions of each. © 2018 Pearson Education, Inc. Module 13.1: The brain develops from a hollow neural tube Brain anatomy . “Typical brain” volume 1200 mL, but size varies • On average, male brain ~ 10% larger than female’s because of body size difference • No correlation between brain size and intelligence © 2018 Pearson Education, Inc. Module 13.1: Brain development Brain development . Central nervous system begins as hollow cylinder— neural tube • Visible by fourth week of development © 2018 Pearson Education, Inc. Module 13.1: Brain development Primary brain vesicles = three swellings at cephalic end of tube . Prosencephalon = forebrain; anterior tip of neural tube . Mesencephalon = midbrain; caudal to prosencephalon . Rhombencephalon = hindbrain; most caudal part; continuous with spinal cord © 2018 Pearson Education, Inc. Module 13.1: Brain development Secondary brain vesicles . By week 5 of development: • Primary brain vesicles subdivide; form secondary brain vesicles © 2018 Pearson Education, Inc. Module 13.1: Brain development Secondary brain vesicles (continued) . Prosencephalon subdivides into: • Diencephalon—becomes major relay/processing center for information headed to/from cerebrum • Telencephalon—expands rapidly; forms cerebrum – Cerebrum continues enlarging to become largest part of brain and cover other regions © 2018 Pearson Education, Inc. Module 13.1: Brain development Secondary brain vesicles (continued) . Rhombencephalon subdivides into: • Metencephalon—caudal to midbrain (mesencephalon) – Forms cerebellum and pons of adult brain • Myelencephalon—becomes medulla oblongata © 2018 Pearson Education, Inc. Brain development © 2018 Pearson Education, Inc. Module 13.1: Review A. Name the three primary brain vesicles. B. Which structures form the secondary brain vesicles? C. Which embryonic brain vesicle develops into the largest region of the adult brain? Learning Outcome: Describe the origins of the different regions of the brain from the embryonic neural tube. © 2018 Pearson Education, Inc. Module 13.2: Each region of the brain has distinct structural and functional characteristics Four major brain regions 1. Cerebrum 2. Cerebellum 3. Diencephalon 4. Brainstem © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Cerebrum . Left and right cerebral hemispheres; divided by deep fissures . Surface • Gyri (folds) and sulci (grooves)—increase surface area © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Cerebral cortex . Superficial layer of gray matter . Thin—1.5–4.5 mm thick . Major cortical functions • Conscious thought • Memory storage and processing • Sensory processing • Control of skeletal muscles © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Cerebellum . Partially hidden by cerebral hemispheres . Second largest brain structure . Makes up 10 percent of brain’s volume, but > 50 percent of its neurons . Major cerebellar functions • Coordinate/modulate motor commands from cerebral cortex © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Diencephalon . Structural/functional link between cerebral hemispheres and rest of CNS . Two parts 1. Thalamus – Sensory relay/ processing 2. Hypothalamus has centers involved with: – Emotions – Autonomic function – Hormone production © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Brainstem . Three parts—midbrain, pons, and medulla oblongata • Midbrain contains nuclei that: – Process visual and auditory information – Control reflexes triggered by them – Helps maintain consciousness • Pons—connects cerebellum/ brainstem – Tracts and relay centers – Somatic and visceral motor control © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Brainstem (continued) . Three parts (continued) • Medulla oblongata – Relays sensory information through brainstem and to the thalamus – Regulates many autonomic functions © 2018 Pearson Education, Inc. Module 13.2: Major brain regions © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Ventricles of the brain . Chambers formed by neural tube expansion during development • Filled with cerebrospinal fluid; lined by ependymal cells © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Ventricular system components . Lateral ventricles—two, one in each cerebral hemisphere . Interventricular foramen connect lateral ventricles to third ventricle . Third ventricle—located in diencephalon . Cerebral aqueduct—slender canal within midbrain; connects third ventricle to fourth ventricle . Fourth ventricle—extends from metencephalon upper part of medulla oblongata • Narrows to become the central canal of spinal cord © 2018 Pearson Education, Inc. Module 13.2: Major brain regions © 2018 Pearson Education, Inc. Module 13.2: Major brain regions Interconnections between ventricles . Corpus callosum—thick tract of white matter that interconnects the cerebral hemispheres . Septum pellucidum—thin partition separating lateral ventricles © 2018 Pearson Education, Inc. Module 13.2: Review A. Describe the role of the medulla oblongata. B. Which region of the brain contains two ventricles? C. Compare the corpus callosum with the septum pellucidum. D. Which region of the brain is enclosed or hidden by the cerebrum? Learning Outcome: Name the four major regions of the brain, and describe their functions. © 2018 Pearson Education, Inc. Module 13.3: The cranial meninges and cerebrospinal fluid protect and support the brain Protection of the brain . Cranial bones . Cerebrospinal fluid . Blood brain barrier . Cranial meninges © 2018 Pearson Education, Inc. Module 13.3: The cranial meninges and cerebrospinal fluid protect and support the brain Cranial meninges . Continuous with spinal meninges . Three layers 1. Dura mater 2. Arachnoid mater 3. Pia mater © 2018 Pearson Education, Inc. Module 13.3: Protection of the brain Dura mater . Two fibrous layers; mostly fused • Periosteal layer (outer layer)—fused to periosteum of cranial bones – No epidural space •
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