Spinal Cord

1. Spinal Cord Chapter 7: Nervous System

2. Spinal Cord • Approximately 17 inches long, pathway for both afferent and efferent impulses. • About the size of a thumb in width • Very well protected by the vertebrae and CSF.

3. Spinal Cord • Humans have 31 pairs of spinal nerves that arise from the spine and exit from the vertebral column to serve the adjoining body • Caudaequina- terminal end of the spinal nerves that travel through the vertebral canal • Means Horse’s tail

4. Vertebral divisions 7 cervical vertebrae Atlas-C1-supports the skull Axis-C2-allows for rotation 12 thoracic vertebrae 5 lumbar vertebrae

5. Gray Matter in the Spinal Cord • In the spinal cord, the posterior projections (dorsal horns) contain association neurons. • Help interpret/translate sensory information • The anterior projections (ventral horns) are made up of gray matter that are part of the somatic nervous system. • These horns fuse together to form the spinal nerves.

6. White Matter • Composed of fiber tracts, traveling to the higher cognition centers, and some traveling from the brain to the spinal cord. • Some even communicate messages from one side of the spinal cord to the other. • Divided into three sections • Posterior, lateral and anterior columns. • Each column contains a number of fiber tracts. • Posterior column-sensory information to the brain. • Lateral/anterior column- ascending and descending motor tracts (cause muscle action)

7. What is a nerve? • Bundle of neurons, found outside of the CNS. • Each nerve is comprised of neuron fibers or processes wrapped in connective tissue. • Endoneurium-protective tissue sheath around a nerve. • Perineurium-combine multiple nerves into a fascicle, or fiber bundle. • Epineurium-a collection of fascicles, bound together by a fibrous sheath to form a cordlike nerve.

8. Cranial Nerves • 12 pairs of cranial nerves • Serve mainly the head and neck • Vagus nerve only one that serves the thoracic and abdominal cavities • Made up of mostly mixed nerves

9. Cranial Nerves Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal

10. Cranial Nerves • Olfactory- Sense of smell-Pt is asked to identify an aroma • Optic- vision-Pt’s vision is tested, eye chart • Oculomotor-vision-PEARL, follow finger • Trochlear-vision-mobility of eye, in conjunction with III

11. Cranial Nerves • Trigeminal- facial sensations of pain, touch and temperature, also involved in jaw movement • Abducens- lateral movement of the eye. Tested with III as well. • Facial- Facial expression and salivary glands. • Vestibulocochlear-hearing and balance. Sounds close to ear. Rombergs test.

12. Cranial Nerves • Glossopharyngeal- ability to swallow • Vagus- tested along with IX, open mouth wide • Accessory- head rotation, resisted shoulder shrug • Hypoglossal- stick out tongue, say “aahh”

13. Autonomic Nervous System Chapter 7.2

14. ANS • Motor subdivision of the PNS • Controls automatic body activities • Regulate cardiac muscle, smooth muscle (inner lining of organs) • Want to maintain homeostasis and a functional environment • +/- Blood Pressure, heart rate, sweat glands, etc.

15. Sympathetic division • Fight or flight • Under extreme conditions the body will increase heart rate, blood pressure and blood glucose levels to assist in a higher level of functioning • Not just under extreme conditions, but when your body is under physical stress, i.e. post-surgically

16. Parasympathetic division • Rest and digest • Most active when the body is at rest • Promoting normal digestion, bowel function and conserving of body energy.

17. Nervous System Development • Formed during the first month of embryonic development • Any infection/disruption can lead to serious complications. • Maternal measles-MMR- can lead to deafness • Smoking- lack of oxygen to the neurons can lead to serious brain damage of the child • Alcohol- can lead to FAS, causes developmental and emotional problems later on in child’s life.