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Download AP10 Ch7 Nervous Sys-student version-2014
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PowerPoint® Lecture Slides Prepared by Patty Bostwick-Taylor, Florence-Darlington Technical College NEED TO SHORTEN CHAPTER 7 The Nervous System © 2012 Pearson Education, Inc. Functions of the Nervous System •Sensory input = •Why: monitor changes inside & outside body •Changes = stimuli •Integration = •Motor output = •Activates muscles or glands © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 7.1 Organization of the Nervous System Structural Classification •Central nervous system (CNS) = •Function © 2012 Pearson Education, Inc. Structural Classification … • Peripheral nervous system (PNS) = • Spinal nerves: • Cranial nerves: • Functions: © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 7.2 Functional Classification Peripheral N.S. … •Sensory (afferent): •Motor (efferent): •For muscles •For Organs © 2012 Pearson Education, Inc. Nervous Tissue Structure & Function: Nervous Tissue Cells •Neuroglia (glial): Support cells •General functions •Support •Insulate •Protect © 2012 Pearson Education, Inc. Nervous Tissue Structure and Function … Neurons •Function: •Parts– •Cell body & • Processes •Cell body •Nissl bodies = rough endoplasmic reticulum •Nucleus © 2012 Pearson Education, Inc. Mitochondrion Dendrite Cell body Nissl substance Axon hillock Axon Neurofibrils Nucleus Collateral branch One Schwann cell Axon terminal Node of Ranvier Schwann cells, forming the myelin sheath on axon (a) © 2012 Pearson Education, Inc. Figure 7.4a Neuron cell body Dendrite (b) © 2012 Pearson Education, Inc. Figure 7.4b Nervous Tissue: Neurons •Processes = •Dendrites: •# •Axons: •# •Axon Hillock •Axon Terminal • Contain Vessicles w/: • Neurotransmitters © 2012 Pearson Education, Inc. Mitochondrion Dendrite Cell body Nissl substance Axon hillock Axon Neurofibrils Nucleus Collateral branch One Schwann cell Axon terminal Node of Ranvier Schwann cells, forming the myelin sheath on axon (a) © 2012 Pearson Education, Inc. Figure 7.4a Neurons … •Axons … • Synaptic cleft—gap between adjacent neurons • Synapse—junction between nerves © 2012 Pearson Education, Inc. Nervous Tissue: Neurons •Myelin sheath = •Nodes of Ranvier— •CNS and PNS © 2012 Pearson Education, Inc. Schwann cell cytoplasm Axon Schwann cell plasma membrane Schwann cell nucleus (a) (b) Neurilemma Myelin sheath (c) © 2012 Pearson Education, Inc. Figure 7.5 Neurons … Terminology •Location cell bodies & Dendrites: •Gray Matter •Nuclei = •Ganglia = •Location AXONS •White matter = •Tracts = •Nerves = © 2012 Pearson Education, Inc. Neurons … Functional Classification of Neurons •Sensory (afferent) neurons = •Motor (efferent) neurons = © 2012 Pearson Education, Inc. Central process (axon) Cell body Sensory neuron Spinal cord (central nervous system) Ganglion Dendrites Peripheral process (axon) Afferent transmission Interneuron (association neuron) Peripheral nervous system Receptors Efferent transmission Motor neuron To effectors (muscles and glands) © 2012 Pearson Education, Inc. Figure 7.6 © 2012 Pearson Education, Inc. Figure 7.7a © 2012 Pearson Education, Inc. Figure 7.7b © 2012 Pearson Education, Inc. Figure 7.7c © 2012 Pearson Education, Inc. Figure 7.7d © 2012 Pearson Education, Inc. Figure 7.7e Functional Classification of Neurons •Interneurons (association neurons) •Found in neural pathways in the central nervous system •Connect sensory and motor neurons © 2012 Pearson Education, Inc. Central process (axon) Cell body Sensory neuron Spinal cord (central nervous system) Ganglion Dendrites Peripheral process (axon) Afferent transmission Interneuron (association neuron) Peripheral nervous system Receptors Efferent transmission Motor neuron To effectors (muscles and glands) © 2012 Pearson Education, Inc. Figure 7.6 Structural Classification of Neurons •Multipolar neurons—many extensions from the cell body •All motor and interneurons © 2012 Pearson Education, Inc. Cell body Axon Dendrites (a) Multipolar neuron © 2012 Pearson Education, Inc. Figure 7.8a Structural Classification of Neurons •Bipolar neurons—one axon and one dendrite •nose and eye © 2012 Pearson Education, Inc. Cell body Dendrite Axon (b) Bipolar neuron © 2012 Pearson Education, Inc. Figure 7.8b Structural Classification of Neurons •Unipolar neurons—have a short single process leaving the cell body •Sensory neurons found in PNS ganglia © 2012 Pearson Education, Inc. Dendrites Cell body Short single process Axon Peripheral process Central process (c) Unipolar neuron © 2012 Pearson Education, Inc. Figure 7.8c PHYSIOLOGY: Nerve Impulses Functional Properties of Neurons •Irritability •Ability to respond to stimuli •Conductivity •Ability to transmit an impulse © 2012 Pearson Education, Inc. Nerve Impulses • Action Potential = Nerve Impulse • The WAVE: movement of arms = ion movement • Stimulus • Ions move a short distance across the plasma membrane • Successive regions of the membrane have ion movement– from point of stimulus to axon terminal © 2012 Pearson Education, Inc. Nerve Impulses = Action Potential •Resting neuron •The plasma membrane charge is polarized •Fewer positive ions are inside the cell than outside the cell • Inside is negative relative to outside and outside is positive + POSITIVE CHARGE __ + __ NEGATIVE CHARGE © 2012 Pearson Education, Inc. + __ Nerve Impulses … • Ion distribution differs inside vs. outside • Inside: more K • Outside: more Na • Cell Membrane impermeable to ions when neuron is at rest + Na+ _ Na+ K+ K+ © 2012 Pearson Education, Inc. K+ Na+ Na+ Na+ K+ K+ Na+ K+ K+ Na+ Nerve Impulses … STIMULUS _ Na+ + Na+ K+ K+ Na+ Na+ Na+ Na+ K+ K+ K+ (1) Stimulus (2) Depolarization = Sodium moves inside neuron The membrane is now permeable to sodium as sodium channels open Sodium (Na+) flows inside the membrane © 2012 Pearson Education, Inc. Nerve Impulses … (3) Repolarization •Potassium ions leave neuron which repolarizes the membrane •Repolarization involves restoring the inside of the membrane to a negative charge and the outer surface to a positive charge + © 2012 Pearson Education, Inc. K+ Na+ Na+ Na+ Na+ Na+ _ Na+ K+ K+ K+ K+ K+ Nerve Impulses … (4) Successive regions of the membrane have ion movement– from point of stimulus to axon terminal K+ K+ Na+ Na+ Na+ Na+ Na+ Na+ K+ K+ K+ K+ © 2012 Pearson Education, Inc. Nerve Impulses … (5) Redistribution of ions Initial ionic conditions are restored using the sodium-potassium pump. Three sodium ions are ejected while two potassium ions are returned Na+ K+ Na+ Na+ Na+ Na+ K+ Na+ K+ K+ K+ K+ © 2012 Pearson Education, Inc. Na+ K+ Na+ Na+ Na+ Na+ K+ Na+ K+ K+ K+ K+ Na+ Na+ K+ Na+ Na+ Na+ Na+ K+ K+ Na+ K+ K+ K+ K+ Na+ Na+ Na+ K+ Na+ Na+Na+ K+ K+ K+ Na+ K+ K+ K+ Na+ Na+ Na+ Na+ K+ Na+ Na+ K+ K+ K+ K+ Na+ K+ K+ © 2012 Pearson Education, Inc. Figure 11.12 Propagation of an action potential (AP). © 2012 Pearson Education, Inc. Nerve Impulses •Impulses travel faster when fibers have a myelin sheath © 2012 Pearson Education, Inc. Transmission of a Signal at Synapses •When action potential reaches the axon terminal, calcium channels open • Calcium diffuses in Axon terminal Ca+ Ca+ Dendrite © 2012 Pearson Education, Inc. Action potential arrives. Ca+ Ca+ Transmission of a Signal at Synapses … (1) Calcium causes vesicles to move to axonal membrane Axon terminal Vesicles 1 Ca+ Dendrite © 2012 Pearson Education, Inc. Ca+ Ca+ Ca+ Figure 7.10, step 1 2 Vesicle fuses with plasma membrane. Ca+ Synaptic cleft Axon terminal of Ca+ Ca+ Neurotransmitter molecules Dendrite © 2012 Pearson Education, Inc. Figure 7.10, step 2 2 Vesicle Transmitting neuron fuses with plasma 3 Neurotransmembrane. mitter is Ca+ released into synaptic cleft. Synaptic cleft Neurotransmitter molecules Dendrite Receiving neuron © 2012 Pearson Education, Inc. Figure 7.10, step 3 Transmission of a Signal at Synapses (3) Neurotransmitters diffuse across to dendrite of receiving cell Axon Terminal Dendrite © 2012 Pearson Education, Inc. 2 Vesicle fuses with plasma membrane. AXON TERMINAL Ca+ 4 3 NeurotransNeurotransmitter binds mitter is to Receptor released into synaptic cleft. . Synaptic cleft Receptors Dendrite © 2012 Pearson Education, Inc. Figure 7.10, step 4 (4) Receptors: a) are proteins that bond with Neurotransmitter © 2012 Pearson Education, Inc. Transmission of a Signal at Synapses (5) If enough neurotransmitter is released, the 2nd neuron will send its own Action potential Neurotransmitter Ion Receptor © 2012 Pearson Education, Inc. 5 Ion channel opens. 6 Receptor channel closes. Ion (7) Neurotransmitter is broken down and released. © 2012 Pearson Education, Inc. Figure 7.10, step 6 The Reflex Arc– Simplest Function •Five elements: •Sensory receptor: •Sensory neuron: •Integration center (CNS)--interneuron: •Motor neuron: •Effector organ: © 2012 Pearson Education, Inc. CNS Functioning– Simplest •Somatic reflexes •Reflexes that stimulate the ____________ •Examples: •Autonomic reflexes •Regulate the activity of ___________ •Examples: © 2012 Pearson Education, Inc. Three-Neuron Reflex Arc •Three-neuron reflex arcs •Have all 5 elements •Example: Flexor (withdrawal) reflex 2 1 Stimulus 3 4 5 © 2012 Pearson Education, Inc. STIMULUS Receptor Sensory Neuron Integration Center-- CNS Motor Neuron Effector 1 Sensory receptor 2 Sensory (afferent) neuron 3 Interneuron 4 Motor (efferent) neuron 5 Effector organ © 2012 Pearson Education, Inc. Figure 7.11c 1 Sensory (stretch) receptor 2 Sensory (afferent) neuron 3 4 Motor (efferent) neuron 5 Effector organ © 2012 Pearson Education, Inc. Figure 7.11b, step 5 Central Nervous System (CNS) Parietal lobe Brain Left cerebral hemisphere Frontal lobe Occipital lobe Temporal lobe Cephalad Caudal (b) © 2012 Pearson Education, Inc. Brain stem Cerebellum Figure 7.13b Central Nervous System (CNS) Brain Regions •**Cerebrum •Thalamus, •**Hypothalamus •**Brain stem •**Cerebellum © 2012 Pearson Education, Inc. Cerebrum • Cerebral Hemispheres • Cerebral Cortex • Primary somatic sensory area • Primary motor area Primary motor area © 2012 Pearson Education, Inc. Primary somatic sensory area •Anterior Association Area •Posterior Association Area •Broca’s area •Speech Area Anterior association area • Working memory and judgment • Problem solving • Language comprehension Broca’s area (motor speech) (c) © 2012 Pearson Education, Inc. Speech/language (outlined by dashes) Posterior association area Primary motor area Premotor area Anterior association area • Working memory and judgment • Problem solving • Language comprehension Broca’s area (motor speech) Olfactory area Central sulcus Primary somatic sensory area Gustatory area (taste) Speech/language (outlined by dashes) Posterior association area Visual area Auditory area (c) © 2012 Pearson Education, Inc. Figure 7.13c Cerebrum … •Corpus Callosum Superior corpus callosum Basal nuclei Pons Medulla oblongata © 2012 Pearson Education, Inc. Longitudinal fissure Lateral ventricle Basal nuclei (basal ganglia) Superior Association fibers Commissural fibers (corpus callosum) Corona radiata Fornix Thalamus Internal capsule Third ventricle Pons Projection fibers Medulla oblongata © 2012 Pearson Education, Inc. Figure 7.15 •Thalamus •Hypothalamus Thalamus & Hypothalamus (b) Adult brain © 2012 Pearson Education, Inc. Brain Stem •Pons •Medulla oblongata © 2012 Pearson Education, Inc. Cerebellum © 2012 Pearson Education, Inc. Items Associated with the Brain •Cerebrospinal Fluid •Meninges •Dura Mater •Arachnoid Mater & Subarachnoid Space •Pia Mater Skin of scalp Periosteum Bone of skull Superior sagittal sinus Subdural space Subarachnoid space (a) © 2012 Pearson Education, Inc. Periosteal Meningeal Dura mater Arachnoid mater Pia mater Arachnoid villus Blood vessel Falx cerebri (in longitudinal fissure only) Occipital lobe Tentorium cerebelli Cerebellum Arachnoid mater over medulla oblongata (b) © 2012 Pearson Education, Inc. Skull Scalp Superior sagittal sinus Dura mater Transverse sinus Temporal bone Figure 7.17b •Ventricles •Blood-brain barrier Lateral ventricle Anterior horn Septum pellucidum Inferior horn Lateral aperture Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Central canal © 2012 Pearson Education, Inc. Lateral ventricle Anterior horn Posterior horn Interventricular foramen Third ventricle Inferior horn Cerebral aqueduct Median aperture Fourth ventricle Lateral aperture Central canal (b) Left lateral view © 2012 Pearson Education, Inc. Figure 7.18b CSF Circulation 4 Superior sagittal sinus Arachnoid villus Subarachnoid space Arachnoid mater Meningeal dura mater Periosteal dura mater Right lateral ventricle (deep to cut) Choroid plexus Corpus callosum 1 Interventricular foramen Third ventricle 3 Cerebral aqueduct Lateral aperture Fourth ventricle Median aperture Central canal of spinal cord (c) CSF circulation Choroid plexus of fourth ventricle 2 1 CSF is produced by the choroid plexus of each ventricle. 2 CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures. Some CSF flows through the central canal of the spinal cord. 3 CSF flows through the subarachnoid space. 4 CSF is absorbed into the dural venous sinuses via the arachnoid villi. © 2012 Pearson Education, Inc. Figure 7.18c Central Nervous System … Spinal Cord •from foramen magnum to 2nd lumbar vertebra • then as a collection of spinal nerves © 2012 Pearson Education, Inc. • Functions: • Relays information between ____ & _____. • Sensory • Motor • Spinal Reflexes © 2012 Pearson Education, Inc. Spinal Cord Anatomy •Meninges © 2012 Pearson Education, Inc. Dorsal root ganglion White matter Central canal Dorsal (posterior) horn of gray matter Lateral horn of gray matter Spinal nerve Dorsal root of spinal nerve Ventral root of spinal nerve Ventral (anterior) horn of gray matter Pia mater Arachnoid mater Dura mater © 2012 Pearson Education, Inc. Figure 7.21 Peripheral Nervous System (PNS) •PNS = Nerves and ganglia •connective tissue © 2012 Pearson Education, Inc. Axon Myelin sheath Endoneurium Perineurium Epineurium Fascicle Blood vessels © 2012 Pearson Education, Inc. Figure 7.23 PNS: Classification of Nerves •Mixed nerves = •Sensory (afferent) nerves = •Motor (efferent) nerves = © 2012 Pearson Education, Inc. PNS: Cranial Nerves •Twelve pairs of nerves •Most are mixed •three are sensory only © 2012 Pearson Education, Inc. Figure 13.6a Location and function of cranial nerves. Filaments of olfactory nerve (I) Frontal lobe Olfactory bulb Olfactory tract Optic nerve (II) Optic chiasma Temporal lobe Optic tract Oculomotor nerve (III) Trochlear nerve (IV) Infundibulum Trigeminal nerve (V) Abducens nerve (VI) Cerebellum Medulla oblongata © 2012 Pearson Education, Inc. Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII) III Oculomotor IV Trochlear VI Abducens I Olfactory II Optic V Trigeminal V Trigeminal VII Facial Vestibular branch Cochlear branch VIII Vestibulocochlear X Vagus IX Glossopharyngeal XII Hypoglossal © 2012 Pearson Education, Inc. XI Accessory Figure 7.24 PNS: Cranial Nerves •I Olfactory nerve—sensory for smell •II Optic nerve—sensory for vision I II © 2012 Pearson Education, Inc. PNS: Cranial Nerves •V Trigeminal nerve—sensory for the face; motor fibers to chewing muscles X Vagus nerves—sensory and motor fibers for pharynx, larynx, and viscera V X © 2012 Pearson Education, Inc. 31 Paired Spinal Nerves Cervical nerves Thoracic nerves Lumbar nerves Sacral nerves C1 2 3 4 5 6 7 8 T1 2 3 4 5 6 7 8 9 10 11 Ventral rami form cervical plexus (C1 – C5) Ventral rami form brachial plexus (C5 – C8; T1) No plexus formed (intercostal nerves) (T1 – T12) 12 L1 2 3 4 Ventral rami form lumbar plexus (L1 – L4) 5 (a) © 2012 Pearson Education, Inc. S1 2 3 4 Ventral rami form sacral plexus (L4 – L5; S1 – S4) Superior gluteal Sciatic Nerve Phrenic Nerve Inferior gluteal Pudendal Sciatic Posterior femoral cutaneous Common fibular Tibial Sural (cut) Deep fibular Superficial fibular Plantar branches © 2012 Pearson Education, Inc. Figure 13.12c The sacral plexus. Gluteus maximus Piriformis Inferior gluteal nerve Common fibular nerve Tibial nerve Pudendal nerve Posterior femoral cutaneous nerve Sciatic nerve Cadaver photo © 2012 Pearson Education, Inc. Peripheral NS … PNS: Autonomic Nervous System • Motor subdivision of the PNS • Involuntary •Two subdivisions © 2012 Pearson Education, Inc. PNS: Autonomic Functioning … •Sympathetic—STRESS “fight or flight” •Exercise, excitement, emergency, embarrassment •unusual stimulus •Increases: • • • • • © 2012 Pearson Education, Inc. Sympathetic … •Decreases activities of unnecessary organ systems during stress • • © 2012 Pearson Education, Inc. Parasympathetic Sympathetic Eye Eye Brain stem Salivary glands Heart Skin Cranial nerves Sympathetic ganglia Salivary glands Cervical Lungs Lungs T1 Heart Stomach Thoracic Stomach Pancreas Pancreas L1 Liver and gallbladder Lumbar Pelvic splanchnic nerves © 2012 Pearson Education, Inc. Adrenal gland Bladder Bladder Genitals Liver and gallbladder Genitals Sacral nerves (S2 – S4) Figure 7.28 PNS: Autonomic Functioning • Parasympathetic—PEACE “housekeeping” •necessary body functions •Increases activities of: • • • Decreases activities of Stress Organ Systems © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 7.2 •END OF PPT © 2012 Pearson Education, Inc. PHYSIOLOGY: Reflexes The Reflex Arc •The simplest type of processing •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 © 2012 Pearson Education, Inc. Stimulus at distal end of neuron Spinal cord (in cross section) Skin 2 Sensory neuron 1 Receptor 4 Motor neuron 5 Effector 3 Integration center Interneuron (a) Five basic elements of reflex arc © 2012 Pearson Education, Inc. Figure 7.11a Withdrawal Reflexes 1 Sensory receptor © 2012 Pearson Education, Inc. Figure 7.11c, step 1 1 Sensory receptor © 2012 Pearson Education, Inc. 2 Sensory (afferent) neuron Figure 7.11c, step 2 1 Sensory receptor 2 Sensory (afferent) neuron 3 Interneuron © 2012 Pearson Education, Inc. Figure 7.11c, step 3 1 Sensory receptor 2 Sensory (afferent) neuron 3 Interneuron 4 Motor (efferent) neuron © 2012 Pearson Education, Inc. Figure 7.11c, step 4 1 Sensory receptor 2 Sensory (afferent) neuron 3 Interneuron 4 Motor (efferent) neuron 5 Effector organ © 2012 Pearson Education, Inc. Figure 7.11c, step 5 [Na+] + –[K ] – + + © 2012 Pearson Education, Inc. 1 Resting membrane is polarized. In the resting state, the external face of the membrane is slightly positive; its internal face is slightly negative. The chief extracellular ion is sodium (Na+), whereas the chief intracellular ion is potassium (K+). The membrane is relatively impermeable to both ions. Figure 7.9, step 1 Na+ + + – – + © 2012 Pearson Education, Inc. 2 Stimulus initiates local depolarization. A stimulus changes the permeability of a local "patch" of the membrane, and sodium ions diffuse rapidly into the cell. This changes the polarity of the membrane (the inside becomes more positive; the outside becomes more negative) at that site. Figure 7.9, step 2 Na+ + + – – + © 2012 Pearson Education, Inc. 3 Depolarization and generation of an action potential. If the stimulus is strong enough, depolarization causes membrane polarity to be completely reversed and an action potential is initiated. Figure 7.9, step 3 – + + – © 2012 Pearson Education, Inc. 4 Propagation of the action potential. Depolarization of the first membrane patch causes permeability changes in the adjacent membrane, and the events described in step 2 are repeated. Thus, the action potential propagates rapidly along the entire length of the membrane. Figure 7.9, step 4 + K+ + – + – © 2012 Pearson Education, Inc. 5 Repolarization. Potassium ions diffuse out of the cell as the membrane permeability changes again, restoring the negative charge on the inside of the membrane and the positive charge on the outside surface. Repolarization occurs in the same direction as depolarization. Figure 7.9, step 5 Na+ Na+ Na+ Diffusion K+ Diffusion Cell exterior Cell interior © 2012 Pearson Education, Inc. Na+ Na+ – K+ pump K+ K+ K+ Plasma membrane 6 Initial ionic conditions restored. The ionic conditions of the resting state are restored later by the activity of the sodium-potassium pump. Three sodium ions are ejected for every two potassium ions carried back into the cell. K+ Figure 7.9, step 6 PHYSIOLOGY: Reflexes The Reflex Arc •The simplest type of processing •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 © 2012 Pearson Education, Inc. • Brain Regions • Cerebrum, Cerebral hemispheres, Cerebral Cortex, • Parietal lobe, Primary Somatic Sensory Area, • Occipital lobe, • Temporal Lobe, • Frontal Lobe, • Special Regions: Primary Somatic Sensory Area, Primary Motor area, Corticospinal Tract, Brocas’s area, Anterior Association Area, Posterior Association Area, Speech Area • Corpus Callosum • Basal Nuclei (Basal Ganglia) • • Diencephalon • Thalamus • Hypothalamus, Limbic System, Pituitary Gland • • Brain Stem • Midbrain • Pons • Medulla Oblongata • Reticular Activating System © 2012 Pearson Education, Inc. • Cerebellum • • Items Associated with the Brain • Meninges • Dura Mater • Arachnoid Mater, Subarachnoid Space • Pia Mater • Cerebrospinal Fluid • Ventricles • Blood-Brain Barrier • • Brain Dysfunctions • Hydrocephalus • Concussion • Contusion • Cerebral Edema • Cerebrovascular Accidents • Transient Ischemic Attack • Alzheimer’s Disease © 2012 Pearson Education, Inc. Precentral gyrus Central sulcus Postcentral gyrus Parietal lobe Frontal lobe Parieto-occipital sulcus (deep) Lateral sulcus Occipital lobe Temporal lobe Cerebellum Pons Medulla oblongata Cerebral cortex (gray matter) Gyrus Spinal cord Sulcus Fissure (a deep sulcus) (a) © 2012 Pearson Education, Inc. Cerebral white matter Figure 7.13a Cerebrum Thalamus + Hypothalamus Cerebellum Brain stem (b) Adult brain © 2012 Pearson Education, Inc. Figure 7.12b Cerebral hemisphere Corpus callosum Choroid plexus of third ventricle Occipital lobe of cerebral hemisphere Thalamus (encloses third ventricle) Pineal gland (part of epithalamus) Corpora quadrigemina Midbrain Cerebral aqueduct Third ventricle Anterior commissure Hypothalamus Optic chiasma Pituitary gland Mammillary body Pons Medulla oblongata Spinal cord Cerebral peduncle of midbrain Fourth ventricle Choroid plexus Cerebellum (a) © 2012 Pearson Education, Inc. Figure 7.16a Occipital lobe Tentorium cerebelli Cerebellum Arachnoid mater over medulla oblongata (b) © 2012 Pearson Education, Inc. Skull Scalp Superior sagittal sinus Dura mater Transverse sinus Temporal bone Figure 7.17b PNS: Differences Between Somatic and Autonomic Nervous Systems Somatic Nervous System Autonomic Nervous System Nerves One-neuron; it originates in the CNS and axons extend to the skeletal muscles served Two-neuron system consisting of preganglionic and postganglionic neurons Effector organ Skeletal muscle Smooth muscle, cardiac muscle, glands Subdivisions None Sympathetic and parasympathetic Neurotransmitter Acetylcholine Acetylcholine, epinephrine, norepinephrine © 2012 Pearson Education, Inc.
