Ch 13 The Spinal Cord (20 TPS) PDF

13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes PowerPoint® Lecture Presentations prepared by Jason LaPres...

13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes PowerPoint® Lecture Presentations prepared by Jason LaPres Lone Star College—North Harris 1 © 2012 Pearson Education, Inc. An Introduction to the Spinal Cord, Spinal Nerves, and Spinal Reflexes Spinal Reflexes Rapid, automatic nerve responses triggered by specific stimuli Controlled by spinal cord alone, not the brain 2 © 2012 Pearson Education, Inc. Figure 13-1 An Overview of Chapters 13 and 14 CHAPTER 14: The Brain Sensory input Motor output over Reflex Effectors Sensory over cranial nerves cranial nerves centers Muscles receptors in brain CHAPTER 13: The Spinal Cord Glands Sensory input Motor output over Reflex over spinal nerves spinal nerves Sensory centers receptors in spinal cord Adipose tissue 3 © 2012 Pearson Education, Inc. 13-2 Spinal Cord Gross Anatomy of the Spinal Cord About 18 inches (45 cm) long 1/2 inch (14 mm) wide Ends between vertebrae L1 and L2 Bilateral symmetry Grooves divide the spinal cord into left and right Posterior median sulcus – on posterior side Anterior median fissure – deeper groove on anterior side 4 © 2012 Pearson Education, Inc.  13-2 Spinal Cord Enlargements of the Spinal Cord Caused by: Amount of gray matter in segment Involvement with sensory and motor nerves of limbs Cervical enlargement Nerves of shoulders and upper limbs Lumbar enlargement Nerves of pelvis and lower limbs 5 © 2012 Pearson Education, Inc.  13-2 Spinal Cord The Three Meningeal Layers 1. Dura mater Outer layer of spinal cord 2. Arachnoid mater Middle meningeal layer 3. Pia mater Inner meningeal layer 6 © 2012 Pearson Education, Inc.  13-2 Spinal Cord The Dura Mater Tough and fibrous Cranially Fuses with periosteum of occipital bone Is continuous with cranial dura mater Caudally Tapers to dense cord of collagen fibers Joins filum terminale in coccygeal ligament 7 © 2012 Pearson Education, Inc. 13-2 Spinal Cord The Dura Mater The Epidural Space Between spinal dura mater and walls of vertebral canal Contains loose connective and adipose tissue Anesthetic injection site 8 © 2012 Pearson Education, Inc.  13-2 Spinal Cord The Arachnoid Mater Middle meningeal layer Arachnoid membrane Simple squamous epithelia Covers arachnoid mater 9 © 2012 Pearson Education, Inc.  The Interlayer Spaces of Arachnoid Mater Subdural space Between arachnoid mater and dura mater Subarachnoid space Between arachnoid mater and pia mater Contains collagen/elastin fiber network (arachnoid trabeculae) Filled with cerebrospinal fluid (CSF) 10 © 2012 Pearson Education, Inc. The Interlayer Spaces of Arachnoid Mater Cerebrospinal Fluid (CSF) Carries dissolved gases, nutrients, and wastes Lumbar puncture or spinal tap withdraws CSF 11 © 2012 Pearson Education, Inc. 13-2 Spinal Cord The Pia Mater Is the innermost meningeal layer Is a mesh of collagen and elastic fibers Is bound to underlying neural tissue 12 © 2012 Pearson Education, Inc.  Sectional Anatomy of the Spinal Cord White matter Is superficial Contains myelinated and unmyelinated axons Gray matter Surrounds central canal of spinal cord Contains neuron cell bodies, neuroglia, unmyelinated axons Has projections (gray horns) 13 © 2012 Pearson Education, Inc.  Organization of Gray Matter The gray horns Posterior gray horns contain somatic and visceral sensory nuclei Anterior gray horns contain somatic motor nuclei Lateral gray horns are in thoracic and lumbar segments; contain visceral motor nuclei Gray commissures Axons that cross from one side of cord to the other before reaching gray matter 14 © 2012 Pearson Education, Inc. 13-3 Gray Matter and White Matter Organization of Gray Matter The cell bodies of neurons form functional groups called nuclei Sensory nuclei Dorsal (posterior) Connect to peripheral receptors Motor nuclei Ventral (anterior) Connect to peripheral effectors 15 © 2012 Pearson Education, Inc.  Organization of White Matter Posterior white columns between posterior gray horns and posterior median sulcus Anterior white columns lie between anterior gray horns and anterior median fissure Anterior white commissure where axons cross the spinal cord Lateral white columns located on each side of spinal cord 16 © 2012 Pearson Education, Inc.  13-4 Spinal Nerves and Plexuses Peripheral Neuropathy Regional loss of sensory or motor function Due to trauma or compression 17 © 2012 Pearson Education, Inc. Paraplegia VS Quadriplegia 18 © 2012 Pearson Education, Inc. 13-5 Neuronal Pools Neuronal Pools Functional groups of interconnected neurons (interneurons) Each with limited input sources and output destinations May stimulate or depress parts of brain or spinal cord 19 © 2012 Pearson Education, Inc. Five Patterns of Neural Circuits in Neuronal Pools 20 © 2012 Pearson Education, Inc. Think Pair Share Pair up with the person sitting next to you and answer the following question. Be prepared to present your answer to the class. Draw a cross section of the spinal cord including the Meningeal Layers and label it. Be prepared to come to the board and draw it. © 2012 Pearson Education, Inc.