BIO10004 Week 5.2 CNS PDF

Spinal cord and brain Dr Greg Davis Martini Chapter 13, 14 Copyright notice  Learning objectives and reading At the end of this lecture you should be able to: 1. Discuss the structure and functions of the spinal cord and describe the three meningeal lay...

Spinal cord and brain Dr Greg Davis Martini Chapter 13, 14 Copyright notice  Learning objectives and reading At the end of this lecture you should be able to: 1. Discuss the structure and functions of the spinal cord and describe the three meningeal layers that surround the central nervous system. 2. Explain and be able to identify the structures of the spinal cord and the role of white and grey matter in relaying motor and sensory information. 3. Describe the distribution of spinal nerves and main nerve plexuses based on their spinal segments and relate their distribution to the general regions of the body that they innervate. 4. Describe the events involved in a reflex arc. 5. Name the four regions of the brain and brainstem and be able to identify the locations and functions of each. 6. Identify the components and functions of the cerebellar structures. 7. Identify the major anatomical subdivisions and functions of the cerebrum, including cortices, main gyri and sulci, and sensory areas of the cortex. Reading guide (textbook): Sections: 13-2, 13-3, 13-6, 13-8; 14-1, 14-2 (p. 515-517), 14-6, 14-9 Figures: 13-2, 13-3, 13-5, 13-7 to 13-9, 13-14, 13-17; 14-1 to14-3, 14-5, 14-9, 14-13, 14-16, 14-18 Questions: 13: 2, 4, 6, 12 (20, 21); 14: 1, 2, 3, 5, 6, 10, 11, (18, 23) CNS layout  The spinal cord Approximately 45 cm long Divided into sections (link vertebrae) – Cervical, thoracic, lumbar and sacral Contains grey and white matter Surrounded by three layers (meninges) – Dura, arachnoid and pia (mater) Spinal cord Spinal cord  Internal organisation Grey (or gray) matter – Neural tissue, neurons, cell bodies – Posterior (dorsal) horn – sensory neurons – Anterior (ventral) horn – motor neurons – Lateral horn – visceral neurons White matter – Neuroglia, myelin sheath encasing axons – Formed into columns moving up or down cord Spinal cord organisation Nerve Plexuses Dermatomes Regions innervated by neurons exiting at the spinal level Some slight differences between motor and sensory function Overlap between adjacent segments  Interaction Sensory information comes in via posterior Motor information goes out via anterior Potential to interact at the level of the spinal cord Reflexes occur here Reflex arc  The brain Most concentrated section of the CNS Contains 4 separate regions – Cerebrum (including cortex) – Cerebellum (motor function) – Diencephalon (sensory processing) – Brainstem (reflex centres) Brain Cerebral areas, sulci and gyri Cerebral areas Cerebellum  Meninges Like the CNS Three layers cover the brain – Dura mater (hard mother) – Arachnoid mater (spider mother) – Pia mater (tender mother) Layers  Summary CNS organization Spinal cord Segment and internal organization – Grey matter, white matter Reflexes Brain – Cerebrum – Cerebellum – Diencephalon – Brainstem Meninges