Lab 11: The Spinal Cord and Peripheral Nervous System PDF

Bio 181: Anatomy & Physiology 1 Lab 02BF Dr. Ayanna Alexander-Street: [email protected] Jeremy Howland: [email protected] Lab 11: The Spinal Cord and Peripheral Nervous System Student Learning Outcomes: Describe the structure of a typical spin...

Bio 181: Anatomy & Physiology 1 Lab 02BF Dr. Ayanna Alexander-Street: [email protected] Jeremy Howland: [email protected] Lab 11: The Spinal Cord and Peripheral Nervous System Student Learning Outcomes: Describe the structure of a typical spinal cord. Describe the structure of and information flow through a spinal nerve and how spinal nerves from the spinal nerve plexuses. Identify the spinal nerve plexuses and which major nerves arise from each plexus. Describe the portions of a reflex arc that includes the spinal cord. Identify the cranial nerves, including their name, numeric designation, nervous information type (sensory, motor, or mixed), and function. The Central Nervous System: Brain and Spinal Cord  Figure 15-15 The gross anatomy of the spinal cord. Spinal Cord – continuous with medulla oblongata Not uniform in diameter and length It has two enlarged regions: 1. Cervical enlargement, which gives rise to nerves that supply the upper limb 2. Lumbar enlargement, which gives rise to nerves that innervate the pelvic region and the lower limb  Figure 15-16 The spinal cord in cross-section. The lateral horns, which are present only in the thoracic and lumbar regions of the cord, contain cell bodies of autonomic motor neurons An anterior root and a posterior root fuse to form a spinal nerve. NB: All spinal nerves contain both sensory and motor neurons and are, therefore, classified as mixed nerves.  Spinal Nerves Figure 16-5 The spinal nerves (at right) and nerve plexuses (at left) Spinal nerves are formed from the union of the posterior and anterior roots of the spinal cord Spinal nerves are mixed nerves because the posterior roots contain sensory neurons entering the spinal cord, and the anterior roots contain the myelinated axons of motor (efferent) neurons whose cell bodies are located in the spinal cord.  Spinal Nerves Figure 16-5 The spinal nerves (at right) and nerve plexuses (at left) In the human body, 31 pairs of spinal nerves emerge from the spinal cord  8 pairs of cervical nerves  12 pairs of thoracic nerves,  5 pairs of lumbar nerves,  5 pairs of sacral nerves, and  1 pair of coccygeal nerves. Sketch NB: The name of each spinal nerve is based on its location of origin. Nerve Plexuses Nerve plexuses - interlacing nerve networks, Located lateral to the vertebral column, Formed from the joining of anterior rami from all vertebrae except T2–T12. Four major nerve plexuses 1. The cervical plexus, 2. The brachial plexus, 3. The lumbar plexus, and 4. The sacral plexus  Nerve Plexuses Figure 16-7 The cervical plexus. Four major nerve plexuses  The cervical plexus, The cervical plexus - arises from the anterior rami of C1–C4 and parts of C5, Located deep to the sternocleidomastoid muscle. The major motor branch of this plexus is the phrenic nerve, which arises from C3, C4, and parts of C5. The phrenic nerve supplies sensory and motor nerve fibers to the diaphragm. Other nerves arising from this plexus serve the scalp, neck, shoulders, and chest.  Figure 16-8 The brachial plexus. Figure 16-8 The brachial plexus The large and complicated brachial plexus arises from the ventral rami of C5– C8 and T1. It successively splits into trunks, then into cords, and finally into five major nerves that serve the shoulders and upper limbs.  Nerve Plexuses Figure 16-9 The lumbar plexus. The lumbar plexus  The lumbar plexus - arises from L1–L4,  Serves the lower abdominopelvic region and the anterior thigh.  The largest nerves that arise from the lumbar plexus are the femoral nerve, which innervates the muscles of the anterior thigh, and the obturator nerve which innervates the adductor muscles of the medial thigh.  Additionally, a cutaneous branch of the femoral nerve, the saphenous nerve, innervates the skin of the anteromedial surface of the thigh and leg.  Nerve Plexuses Figure 16-10 The sacral plexus. The sacral plexus  The sacral plexus - arises from L4–S4.  Serves the buttocks and posterior thigh  Gives rise to most of the sensory and motor fibers of the leg and foot.  The largest nerve arising from the sacral plexus—the sciatic nerve -is the largest nerve in the body.  It travels along the posterior thigh and divides in the popliteal region to form the tibial nerve and the common fibular nerve. Reflex Arcs SKETCH Activity 4: Analyzing a Spinal Reflex Patellar Tendon Reflex Watch Pre-Lab Video: Stretch Reflexes: Pg 358 BREAK Cranial Nerves The cranial nerves serve structures of the head and neck only. The 12 pairs of cranial nerves pass through the various foramina of the skull  Cranial Nerves Figure 16-1 The sensory cranial nerves.  Three of the cranial nerves (I, II, and VIII) are classified as sensory nerves  Cranial Nerves Figure 16-2 The motor cranial nerves  Five (III, IV, VI, XI, and XII) as motor nerves (M)  Cranial Nerves Figure 16-4 Two mixed cranial nerves: the glossopharyngeal and vagus nerves (not to scale).  Four (V, VII, IX, and X) as mixed nerves PAL 4.0 Peripheral Nervous System Tab What would happen if cranial nerve is damaged? Announcements Last Quiz (#5) next week (December 2nd) on Chapters 10 and 11. If you bring your completed lab supplemental (December 9th) to the practical, you will receive extra credit.