Neurophysiology: Spinal Cord (Summer 2024) PDF

Andre Azevedo, DVM, MSc Locum Professor of Veterinary Physiology [email protected]  At the end of the lecture, students should be able to: List the functions of the spinal cord Know the organization of gray and white matter in the spinal cord List and localize th...

Andre Azevedo, DVM, MSc Locum Professor of Veterinary Physiology [email protected]  At the end of the lecture, students should be able to: List the functions of the spinal cord Know the organization of gray and white matter in the spinal cord List and localize the type of fibers located in the dorsal and ventral roots of the spinal cord List and localize the 5 functional regions of the spinal cord  The spinal cord has a variety of functions, including: Receiving and distributing information from the PNS Sensory system Relaying afferent/sensory information to the brain centers Local integration of sensory and motor functions for reflex activity Reflexes Both within a limb and between limbs Relaying efferent/motor information from motor management centers via specific tracts (upper motor neurons - UMN) to connect with lower motor neurons (LMN) Motor system Contain interneurons and complex neural circuits for motor control CENTRAL PATTERN GENERATORS  The spinal cord is protected by the vertebral column 5 anatomical regions based on the vertebral column 5 functional regions based on the innervation of the limbs ANATOMICAL REGIONS NUMBER OF VERTEBRAS, SPINAL CORD SEGMENTS, AND THE RELASHIONSHIP BETWEEN THEM CAUDA EQUINA Tail end of the spinal cord and the adjacent nerve roots (PNS) SACRUM THE DOG’S CERVIVAL SPINAL CORD HAS THE DOG’S SPINAL CORD FINISHES AT THE 7 VERTEBRAS AND 8 CORD SEGMENTS LEVEL OF THE 5th-6th LUMBAR VERTEBRA  In the transverse section the spinal cord is tubular with a small central canal filled with CSF It is divided anatomically into: PERIPHERAL WHITE MATTER CENTRAL GREY MATTER  DORSAL FUNICULUS LATERAL PERIPHERAL WHITE MATTER FUNICULUS axons SENSORY TRACTS MOTOR TRACTS VENTRAL FUNICULUS  CENTRAL GRAY MATTER neuronal cell bodies dorsal ROOT if Ventral ROOT  CENTRAL GRAY MATTER dorsal LMN ventral  The cord grey matter is the integrative area for the cord reflexes Sensory signals enter the cord almost entirely through the sensory roots Dorsal horn After entering the cord, every sensory signal travels to 2 separate destinations 1. One branch terminates in the grey matter and elicits local reflexes 2. Another branch transmits signals to higher levels of the nervous system Higher levels of the cord, brainstem, and or cerebral cortex  The cord grey matter is the integrative area for the cord reflexes  UMN x LMN  Functional regions http://vanat.cvm.umn.edu/neurLab2/pages/SpCdlSectLevels.html  Functional regions based on the innervation of the limbs (intumescences) http://vanat.cvm.umn.edu/neurLab2/pages/SpCdlSectLevels.html  Functional regions based on the innervation of the limbs (intumescences) C1-C5 C6-T2 T3-L3 L4-S3 Cd1-cd5 Veterinary Neuroanatomy: A Clinical Approach, 2012, Saunders/Elsevier. FOREBRAIN CEREBELLUM BRAINSTEM C1-C5 C6-T2 T3-L3 L4-S3 PERIPHERAL VESTIBULAR CAUDA EQUINA SYSTEM DIFFUSE NEUROMUSCULAR