1. What is the Brain?
Billions of nerve cells

2. What is the Brain?
Thousands of connections where one neuron may interact (communicate) with other neurons.
As many as 10,000 connections
40+ neurochemicals ( neurotransmitters)

3. Overarching Principles of Brain function
Hierarchically organized
Redundant control
Inhibition
Automaticity
Conscious vs Unconscious processes

4. NUTS AND BOLTS to get started

5. Planes of orientation

6. Confusing terms (Particularly where the CNS makes its’ 90 degree bend)
Anterior-Posterior/Rostral-Caudal
Dorsal-ventral/ Superior-inferior

7. Dorsal fins

11. The basic unit of the nervous system

12. Myelin gives a whitish appearance because its adipose content
Shwann cells myelinate the PNS

13. Oligodendrocytes myelinate the CNS

14. White matter and gray matter reflect organization

15. Staining for myelin in the brain coronal section

16. Myelin Staining in the Spinal cord
Dorsal
Horizontal plane
ventral

17. Organizational schemes always have shortcomings: The PNS can not be truly separated from the CNS

18. To consider the PNS we first must consider the spinal cord The vertebral column

21. Each vertebra houses a spinal cord segment
Midsaggital view

22. Each segment is similar: Central gray and surrounding white matter

25. Central gray: Dorsal = sensory Ventral = motor

26. Each segment gives rise to nerve pairs: i.e. The PNS

27. 31 peripheral nerve pairs

28. Each nerve pair contains thousands of incoming and outgoing axons

30. The PNS:All neural tissue outside of the cranium and vertebral column ( with one exception)

31. Major divisions of the PNS

33. motor output to skeletal muscles

34. And somatosensory input

36. The somatic division of the PNS gives rise to segmental organiztion: Dermatomes and myotomes

38. The autonomic division

39. The other subdivision of the PNS-the ANS

40. The sympathetic chain

41. Sympathetic activation may be magnified by adrenal gland

42. Some functional differences between the somatic branch and the ANS

43. THE CNS

44. Exception- The cranial nerves