14 The Brain and Cranial Nerves C h a p t e r PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

An Introduction to the Brain and Cranial Nerves The Adult Human Brain Ranges from 750 cc to 2100 cc Contains almost 97% of the body’s neural tissue Average weight about 1.4 kg (3 lb) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Four Main Regions of the Brain Cerebrum Cerebellum Diencephalon Brain Stem 3D Peel-Away of the Brain Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Cerebrum Largest part of brain Controls higher mental functions Divided into left and right cerebral hemispheres Surface layer of gray matter (neural cortex) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Cerebrum Neural cortex Also called cerebral cortex Folded surface increases surface area Elevated ridges (gyri) Shallow depressions (sulci) Deep grooves (fissures) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Cerebellum Second largest part of brain Coordinates repetitive body movements Two hemispheres Covered with cerebellar cortex Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Diencephalon Located under cerebrum and cerebellum Links cerebrum with brain stem Three divisions Left thalamus Right thalamus Hypothalamus Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Diencephalon Thalamus Hypothalamus Pituitary gland Relays and processes sensory information Hypothalamus Hormone production Emotion Autonomic function Pituitary gland Major endocrine gland Connected to hypothalamus Via infundibulum (stalk) Interfaces nervous and endocrine systems Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Processes information between Includes Spinal cord and cerebrum or cerebellum Includes Mesencephalon Pons Medulla oblongata Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Mesencephalon Pons Also called midbrain Processes sight, sound, and associated reflexes Maintains consciousness Pons Connects cerebellum to brain stem Is involved in somatic and visceral motor control Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Medulla oblongata Connects brain to spinal cord Relays information Regulates autonomic functions: heart rate, blood pressure, and digestion Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Figure 14–1 An Introduction to Brain Structures and Functions. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Physical protection Bones of the cranium Cranial meninges Cerebrospinal fluid Biochemical isolation Blood–brain barrier Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support The Cranial Meninges Have three layers: Dura mater Arachnoid mater Pia mater Are continuous with spinal meninges Protect the brain from cranial trauma Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support The Cranial Meninges Dura mater Inner fibrous layer (meningeal layer) Outer fibrous layer (endosteal layer) fused to periosteum Venous sinuses between two layers Arachnoid mater Covers brain Contacts epithelial layer of dura mater Subarachnoid space: between arachnoid mater and pia mater Pia mater Attached to brain surface by astrocytes Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Figure 14–3a The Relationship among the Brain, Cranium, and Meninges. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Figure 14–3b The Relationship among the Brain, Cranium, and Meninges. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Cerebrospinal Fluid (CSF) Surrounds all exposed surfaces of CNS Interchanges with interstitial fluid of brain Functions of CSF Cushions delicate neural structures Supports brain Transports nutrients, chemical messengers, and waste products Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Cerebrospinal Fluid (CSF) CSF circulates From choroid plexus Through ventricles To central canal of spinal cord Into subarachnoid space around the brain, spinal cord, and cauda equina Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Figure 14–4 The Formation and Circulation of Cerebrospinal Fluid. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Figure 14–4a The Formation and Circulation of Cerebrospinal Fluid. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Figure 14–4b The Formation and Circulation of Cerebrospinal Fluid. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Blood–Brain Barrier Isolates CNS neural tissue from general circulation Formed by network of tight junctions Between endothelial cells of CNS capillaries Lipid-soluble compounds (O2, CO2), steroids, and prostaglandins diffuse into interstitial fluid of brain and spinal cord Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Blood–CSF Barrier Formed by special ependymal cells Surround capillaries of choroid plexus Limits movement of compounds transferred Allows chemical composition of blood and CSF to differ Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Four Breaks in the BBB Portions of hypothalamus Secrete hypothalamic hormones Posterior lobe of pituitary gland Secretes hormones ADH and oxytocin Pineal glands Pineal secretions Choroid plexus Where special ependymal cells maintain blood–CSF barrier Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Brain Protection and Support Meninges stabilize brain in cranial cavity Cerebrospinal fluid protects against sudden movement CSF provides nutrients and removes wastes Blood–brain barrier and blood–CSF barrier Selectively isolate brain from chemicals in blood that might disrupt neural function Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5a The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5b The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5c The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–6a The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–6b The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons The Pons Links cerebellum with mesencephalon, diencephalon, cerebrum, and spinal cord Sensory and motor nuclei of cranial nerves V, VI, VII, VIII Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6a The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6b The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6c The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Figure 14–7a The Cerebellum. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Figure 14–7b The Cerebellum. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Structures of the Mesencephalon Cerebral peduncles Tectum Two pairs of sensory nuclei (corpora quadrigemina): superior colliculus (visual) inferior colliculus (auditory) Cerebral peduncles Contain: descending fibers to cerebellum motor command fibers Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Figure 14–8a The Mesencephalon. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Figure 14–8b The Mesencephalon. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Thalamus, epithalamus, and hypothalamus The pineal gland Found in posterior epithalamus Secretes hormone melatonin Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon The Thalamus The third ventricle Separates left thalamus and right thalamus Interthalamic adhesion (or intermediate mass): projection of gray matter extends into ventricle from each side Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–9 The Thalamus. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–9a The Thalamus. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–9b The Thalamus. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon [INSERT Table. 14.5] Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–10a The Hypothalamus in Sagittal Section. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–10b The Hypothalamus in Sagittal Section. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum The Cerebrum Is the largest part of the brain Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Gray matter White matter In cerebral cortex and basal nuclei White matter Deep to basal cortex Around basal nuclei Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Structures of the Cerebrum Gyri Longitudinal fissure Increase surface area (number of cortical neurons) Longitudinal fissure Separates cerebral hemispheres Lobes Divisions of hemispheres Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Structures of the Cerebrum Central sulcus divides Anterior frontal lobe from posterior parietal lobe Lateral sulcus divides Frontal lobe from temporal lobe Parieto-occipital sulcus divides Parietal lobe from occipital lobe Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12a The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12b The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12c The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings