1. Nervous System

2. Some Interesting Facts 85 billion (85,000,000,000) neurons in the human brain. 3,000 years one cell/second 1 neuron cell body = 10 microns wide 85,000,000,000 neurons = 850 km If you use a basketball (diameter = ~24 cm) as the cell body, then your axon would have to be 240,000 cm (2.4 kilometers) in length!

3. ► A baby's brain is a mystery. ► The mystery begins in the womb -- only four weeks into gestation the first brain cells, the neurons, are already forming at an astonishing rate: 250,000 every minute. ► Billions of neurons will form links with billions of other neurons and eventually there will be trillions and trillions of connections between cells. ► Every cell is precisely in its place, every link between neurons carefully organized. Nothing is random, nothing by chance.

4. CNS Development

5. Functions of the Nervous System 1. Sensory input  changes = stimuli 2. Integration  processing 3. Motor output  response to stimuli (The response activates muscles or glands)

6. Neuron Slide 7.10  Extensions outside the cell body  Dendrites – toward the cell body  Axons – away from the cell body Figure 7.4a

7. Neurons

8. Figure 12.2b Glial Cells

10. Anatomy of the Nervous System Slide 7.2  Central nervous system (CNS)  Brain  Spinal cord  Peripheral nervous system (PNS)  Nerve outside the brain and spinal cord

12. Central nervous system (CNS) – Brain – Spinal cord CNS is protected by Bone Meninges CSF

13. Bone

14. Meninges

15. CSF

16. Spinal cord

18. CSF ? LP?

22. Structure of spinal cord Roots dorsal, ventral Horns anterior, posterior, lateral Columns anterior, posterior, lateral

23. Dorsal Ventral White Matter Gray Matter Central Canal Spinal Cord

24. Gray Matter Dorsal Lateral Ventral Horns

25. v v

26. Root dorsal, ventral Nerve Ramus/Brunch anterior, posterior

27. Dorsal Ventral White Matter Spinal Cord Spinal Cord White Matter

28. Ascending (Sensory) Figure 16.1 touch & conscious proprioception pain & temperature unconscious proprioception

29. Descending (motor) Muscle movement Muscle balance

30. Brain