LAB 9: CRANIAL & SPINAL NERVES AND REFLEX PHYSIOLOGY Exercises 18, 19, 21 and 22Teacher Course Evaluations • TCEs will be available ONLINE from April 21st and will CLOSE on May 7th • If 80% of the lab sections complete these surveys, there will be a “free” question on the practical – essentially automatic 2 pts. • Reminders will be on D2L as wellAgenda • Pre-Labs • Quiz • Exercise 21 • Cranial Nerves • Exercise 18 • Spinal Nerves • Exercise 19 • Somatic Reflexes • Exercise 22 • Autonomic ReflexesFew things to clear upEXERCISE 21: CRANIAL NERVESBefore we start.. • Remember that NERVES are part of the PNS while TRACTS are part of the CNS • Nerve – bundle of axons in PNS • Tract – bundle of axons in CNS • CNs therefore can be sensory, motor or both (afferent, efferent or both) • Cranial Nerves are numbered with roman numerals I to XII• Action: Smell • Function: Sensory Olfactory (I)Optic (II) • Action: Vision • Function: SensoryOculomotor (III) • Action: Movement of eyelid and eyeball, accommodation of lens, and pupillary constriction • Function: MotorTrochlear (IV) • Action: Movement of eyeball • Function: MotorTrigeminal (V) • Action: Cutaneous sensations from opthalmic, maxillary, and mandibular areas; chewing • Function: BothAbducens (VI) • Action: Movement of eyeball • Function: MotorFacial (VII) • Action: Taste, facial expression, tear secretion, and salivation • Function: BothVestibulocochlear (VIII) • Action: Equilibrium and hearing • Function: SensoryGlossopharyngeal (IX) • Action: Taste, swallowing, speech, saliva secretion • Function: BothVagus (X) • Action: Taste and somatic sensation from pharynx and epiglottis; swallowing, coughing, and voice production; smooth muscle contraction of GI tract; slow heart rate; secretion by digestive glands • Function: BothAccessory (XI) • Action: • Cranial portion: Swallowing • Spinal portion: Movement of head and shoulders • Function: MotorHypoglossal (XII) • Action: Speech and swallowing • Function: MotorMnemonics for Cranial Nerves • Mnemonic for Order of Cranial Nerves (I-XII) • “On Old Olympus Towering Top, A Friendly Viking Grew Vines And Hops • Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, (Spinal) Accessory, Hypoglossal • Mnemonic for Function of Cranial Nerves • Some Say Marry Money, But My Brother Say Big Brains Matter Most • S=Sensory M=Motor B=BothInformation to Skip… • Skip Table 21.1 on pg. 322 (foramen) • Skip Activity 2 and Table 21.3 on pg. 326 • Skip the “distribution” column of Table 21.2 (you need to know the rest)Activity Time – Sheep Brains and Models • Specimen – pg. 312-314. Review • Need to identify: CN I, II, and V on the sheep brain • Must be able to identify ALL CNs on the models and their functionsEXERCISE 18: SPINAL NERVESIntroduction • Send information between the PNS and CNS • Peripheral sensory receptors to the spinal cord • From the spinal cord to various effectors • 31 pairs of spinal nerves • Emerge bilaterally from spinal cord • Help to mediate spinal reflexes as well (more on this later)Connective Tissue Coverings of Spinal Nerves • Epineurium • Surrounds whole nerve • Perineurium • Surrounds each fascicle • Endoneurium • Covers myelinated and unmyelinated axonsSpinal Nerve Divisions and Spinal Plexus • Divisions • 8 Cervical • 12 Thoracic • 5 Lumbar • 5 Sacral • 1 Coccygeal • Plexus (braided network of spinal nerves) • Cervical • Brachial • Lumbar • Sacral Cervical plexus Brachial plexus Lumbar plexus Sacral plexus Cervical nerves Thoracic nerves Lumbar nerves Sacral nerves Coccygeal nervesPosterior view of entire spinal cord and portions of spinal nerves!CERVICAL PLEXUS (C1–C5):!Lesser occipital nerve!Great auricular!Ansa cervicalis!Transverse cervical nerve!Supraclavicular nerve!Phrenic nerve!BRACHIAL PLEXUS (C5–T1):!Musculocutaneous nerve!Axillary nerve!Median nerve!Radial nerve!Ulnar nerve!Intercostal (thoracic) nerves!Subcostal nerve (intercostal nerve 12)!LUMBAR PLEXUS (L1–L4):!Iliohypogastric nerve!Ilioinguinal nerve!Genitofemoral nerve!Lateral femoral cutaneous nerve!Femoral nerve!Obturator nerve!SACRAL PLEXUS (L4–S4):!Superior gluteal nerve!Inferior gluteal nerve!Sciatic nerve:!Common fibular nerve!Tibial nerve!CERVICAL NERVES (8 pairs)!THORACIC NERVES (12 pairs)!LUMBAR NERVES (5 pairs)!SACRAL NERVES (5 pairs)!COCCYGEAL NERVES (1 pair)!C1!C2!C3!C4!C5!C6!C7!C8!T1!T2!T3!T4!T5!T6!T7!T8!T9!T10!T11!T12!L1!L2!L3!L4!L5!S1!S2!S3!S4!S5!Cervical Plexus • A plexus of the first 4 spinal nerves • C1-C4 • Nerves exit lateral to transverse processes • Form anastomoses • Nerves are deep to the SCM muscleCervical Plexus • Paired nerve: Phrenic • Receives info from respiratory centers in medulla and pons • Innervates diaphragmBrachial Plexus • Plexus of the lower 4 cervical spinal nerves and the first thoracic spinal nerve • C4 – T1 • Innervates the upper limb • Muscular and cutaneous innervation • Exception of trapezius (XI)Brachial PlexusBrachial Plexus • Axillary • Deltoid and teres minor muscles • Musculocutaneous • Anterior muscles of arm • Ulnar • Flexor carpi ulnaris, flexor degitorum profundus, most hand muscles • Median • Muscles of anterior forearm (except muscles supplied by ulnar nerve), some hand muscles • Radial • Muscles of posterior arm and forearmLumbar Plexus • This plexus is located in the lumbar region • L1-L4 • Also some contribution from subcostal nerve (T12) • Helps to innervate area of the pelvis and thigh • Both cutaneous and muscular • Nerves exit to the lower limb under inguinal ligament or through obturator foramenLumbar Plexus • Femoral • Iliacus, quadriceps femoris, sartorius, pectineus • Obturator • Adductor longus, brevis and part of magnus, gracilisSacral Plexus • Originates in the lower lumbar spine and terminates at the coccyx • L5-S4 • Some contribution from L4 • Branches innervate