XAM 4 BSC 2085 - FSU YUNG SU, BSCL2085 EXAM 2 YUNG SU FSU, BSC 2085 EXAM #2 YUNG SU FSU TEST BANK ALL EXAMS

Spinal Reflexes are controlled by: Spinal cord alone, not the brain Spinal Reflexes rapid, automatic nerve responses triggered by specific stimuli can involve a single spinal segment or multiple segments 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 Bilateral Symmetry of Spinal Cord: - Gray matter surrounded by white matter - Grooves divide the spinal cord into left and right: posterior median sulcus and anterior median fissue Enlargements of the Spinal Cord are Caused by: - Amount of gray matter in segment (more gray matter since more cells in these areas for limbs) - Involvement with sensory and motor nerves of limbs Posterior Median Sulcus on posterior side of spinal cord Anterior Median Fissue deeper groove on anterior side of spinal cord Cervical enlargement - around the level of C6 - Nerves of shoulders and upper limbs Lumbar enlargement - around the level of T11 - Nerves of pelvis and lower limbs The distal end of the Spinal Cord: Conus medullaris Filum Terminale Cauda Equina Conus medullaris Thin, conical spinal cord below lumbar enlargement Filum terminale Thin thread of fibrous tissue at end of conus medullaris Attaches to coccygeal ligament Cauda Equina Nerve roots (ventral and dorsal) extending below conus medullaris and into sacrum There are 31 Spinal Cord Segments that... Based on vertebrae where spinal nerves originate Positions of spinal segment and vertebrae change with age (as vertebral column grows, dorsal and ventral roots elongate): Cervical nerves and other nerves Cervical Nerves: Named for inferior vertebra (nerve exists under the vertebra it is named after) Except for cervical nerve 8 (since cervical vertebra 8 does not exist!) All other nerves named for superior vertebra Roots (two branches of spinal nerves) Ventral root & Dorsal Root Ventral Root Contains axons of motor neurons (somatic and visceral effectors) Dorsal root Contains axons of sensory neurons (somatic and visceral) Dorsal root ganglia Contain cell bodies of sensory neurons Note: the cell bodies of the motor neurons that extend axons through the ventral root are located... in the gray matter of the spinal cord The Spinal Nerve: - each side of spine: dorsal and ventral roots join to form a spinal nerve - Mixed Nerves: carry both afferent (sensory) and efferent (motor) fibers The Spinal Meninges: - Specialized membranes isolate spinal cord from surroundings - Continuous with cranial meninges - Functions of the spinal meninges include: Protecting spinal cord,& Carrying blood supply (in epidural & subarachnoid space) Meningitis - Viral or bacterial infection of meninges - Spinal meningitis or cerebral meningitis can disrupt CSF flow, damage or kill neurons and neuroglia - Later stages of meningitis affects entire meningeal system The three Meningeal Layers: 1. Dura mater 2. Arachnoid mater 3. Pia mater Dua mater outer layer of spinal cord Arachnoid mater middle meningeal layer Pia mater inner meningeal layer 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 film terminals in coccygeal ligament The Epidural space Between spinal dura mater and walls of vertebral canal Contains loose connective and adipose tissue Adipose tissue acts as protective padding Anesthetic injection site: Epidural block - temporary sensory loss and possibly some motor paralysis (mostly just sensory loss though). Used at inferior lumbar/sacral region for pain control during childbirth Only affects spinal nerves in immediate area The Arachnoid Mater: Middle meningeal layer Arachnoid membrane: Simple squamous epithelia, Covers outer surface of arachnoid mater The Interlayer Spaces of Arachnoid Mater: Subdural space, Subarachnoid space, Cerebrospinal Fluid (CSF) Subdural space Between arachnoid mater and dura mater Subarachnoid space Between arachnoid mater and pia mater Contains collagen/elastin fiber network (arachnoid trabeculae) - extends to filum terminale Filled with cerebrospinal fluid (CSF) Dorsal and ventral roots of cauda equina located in subarachnoid spa