FLIPPED LECTURE PREVIEW OF OVERVIEW OF NERVOUS SYSTEM 2: GUIDE TO PROSECTIONS OF BACK AND

IDENTIFY - ALL LABELED STRUCTURES - PARTICULARLY - Dorsal and Ventral Rootlets; Dorsal and Ventral roots - Dorsal root ganglia - - ; Denticulate ; - Conus medullaris and Cauda Equina - Abnormal spinal curvature - Scoliosis

CLINICAL APPLICATIONS (SAMPLING , EPIDURAL ANESTHESIA) IN LECTURE SPINAL NERVE: DORSAL ROOT GANGLIA

Grey matter - White matter DORSAL Cell bodies, - axons; form DORSAL ROOT SENSORY ROOTLETS dendrites, etc. tracts, columns GANGLION - (AFFERENT) LOCATION OF CELL ONLY DORSAL BODIES OF ROOT SENSORY NEURONS DORSAL ROOT GANGLION

VENTRAL VENTRAL ROOT - MOTOR VENTRAL ROOT - (EFFERENT) ROOTLETS MOTOR SPINAL (EFFERENT) SPINAL NERVE - NERVE - SENSORY SENSORY AND AND MOTOR MOTOR

- Dorsal Roots; contain sensory (afferent) axons ; Ventral Roots; contain motor (efferent) axons - Dorsal and Ventral roots unite to form a Spinal Nerve; contains sensory and motor axons - Sensory cell bodies located in Dorsal Root Ganglia CLINICALLY TEST NERVOUS SYSTEM FUNCTION BY REFLEXES = STEREOTYPED MOTOR RESPONSES TO SPECIFIC SENSORY STIMULI

SENSORY CELL BODIES IN DORSAL ROOT GANGLIA

SENSORY AFFERENT - RECEPTORS IN SENSORY MUSCLE IN (MUSCLE DORSAL SPINDLES) ROOT EFFERENT - MOTOR IN VENTRAL ROOT SENSORY RECEPTORS IN SKIN OF FOOT

STRETCH (DEEP TENDON) REFLEX – FLEXOR REFLEX – STIMULUS - Stretch muscle (tendon tap) STIMULUS - Stepping on nail causes pain MOTOR RESPONSE - Muscle contracts MOTOR RESPONSE - Lift leg PROSECTION 43: DORSAL AND VENTRAL ROOTS, DORSAL ROOT GANGLIA

- Cell bodies of all sensory neurons projecting to spinal cord are located in Dorsal Root Ganglia - CONNECTIVE TISSUE MEMBRANES SURROUND AND PROTECT SPINAL CORD IN VERTEBRAL CANAL

SPINAL CORD PIA MATER

DURA MATER ARACHNOID

DURA MATER - tough outer layer, looks white on prosections

? ARACHNOID - inside Dura, hard to see on prosections Which way is PIA MATER - the nose delicate layer, closely pointing? adherent to spinal cord

What is this indentation? What is this swelling? MENINGES - connective tissue layers surround and protect spinal cord

DURA SPINAL CORD MATER

EPIDURAL SPACE - separates DURA from PIA inner side MATER of Vertebral DURA MATER Canal

ARACHNOID DENTICULATE LIGAMENTS - extensions of Pia mater from surface of spinal cord to inner side of Dura - stabilize spinal cord; use as surgical landmarks

DENTICULATE LIGAMENTS - EXTENSIONS OF PIA MATER DENTICULATE LIGAMENTS - EXTENSIONS OF PIA MATER

PIA MATER

LOCATION OF SPINAL CORD IN VERTEBRAL CANAL Spinal cord does not extend whole length of vertebral canal. Conus medullaris - is inferior (caudal) end of spinal cord

Conus medullaris - Inferior end of Spinal Cord

L1 VERTEBRA - Vertebrae lengthen as Cauda a child grow to an adult. Equina - - Spinal cord does not roots of show equivalent Lumbar, Sacral increase in length Spinal Spinal Nerves cord ends Adult - Conus medullaris is at level L1 here Newborn - Conus medullaris is level L3 FILUM TERMINALE - extension of Pia Mater that attaches inferiorly at Co1 (First Coccygeal Vertebra), anchors spinal cord

PROSECTION 44 ABNORMAL SPINAL CURVATURES

KYPHOSIS SCOLIOSIS LORDOSIS

- exaggerated CONCAVE ANTERIORLY - abnormal LATERAL - exaggerated CONCAVE (often in Thorax) CURVATURE POSTERIORLY - associate with OSTEOPOROSIS - can be due to presence - normal in PREGNANCY - note: KYPHOSIS IN THORAX CAN of HEMIVERTEBRA - can cause back pain in PRODUCED COMPENSATORY LORDOSIS (half of vertebra not OBESE PATIENTS IN NECK develop)