1. THE NERVOUS SYSTEM
JOSE S. SANTIAGO M.D.

2. Nervous System CNS (central nervous system) Peripheral nervous system
Spinal cord
Brain
Peripheral nervous system
Sensory neurons
Motor neurons

3. Functions of the Nervous System
Sensory input – gathering information
To monitor changes occurring inside and outside the body
Changes = stimuli
Integration
To process and interpret sensory input and decide if action is needed

4. Functions of the Nervous System
Motor output
A response to integrated stimuli
The response activates muscles or glands

5. Nerve Cells
Neurons
Cell body
Axon
Some have myelin sheath
Dendrites

6. Neuron Anatomy
Cell body
Nucleus
Large nucleolus
Figure 7.4a

7. Neuron Anatomy Extensions outside the cell body
Dendrites – conduct impulses toward the cell body
Axons – conduct impulses away from the cell body
Figure 7.4a

8. Nerve Cells Neuroglia Do not carry electrical impulses
Protect the neurons by phagocytosis
Provide nutrients

9. Synapses Synapse Electrical impulse transmission
Gap between neuron and a muscle or between two neurons

10. Synapses Neurotransmitters of the peripheral nervous system
Released from sac at end of neuron
Acetylcholine and Norepinephrine

11. The Brain Part of the CNS Cerebrum
Hemispheres divided by longitudinal fissure
Corpus callosum connect the hemispheres
Cerebral cortex

12. The Brain Cerebrum Gyri (convolutions) Lobes Sulci and fissures
Frontal, parietal, temporal, and occipital

13. Cerebral Hemispheres (Cerebrum)
The surface is made of ridges (gyri) and grooves (sulci)
Figure 7.13a

14. Brain

15. Brain
Thalamus
Hypothalamus

16. Brain
Brain stem
Midbrain
Pons
Medulla oblongata
Cerebellum

17. The Spinal Cord Part of the CNS
Starts at the medulla oblongata and ends at the conus medullaris (level of body of L1 vertebra)

18. The Spinal Cord 31 pairs of nerves 8 cervical 12 thoracic 5 lumbar
5 sacral
1 coccygeal

19. Spinal Cord Meninges - protective membranes
Dura mater-tough, protective connective tissue; tightly bound to the skull; encases the cerebral veins

20. Spinal Cord Arachnoid mater- web-like strands of connective tissue
Pia mater- thin permeable membrane

21. Spinal Cord Subdural space
Subarachnoid space- contains CSF and arteries
Cerebrospinal fluid- secreted by the choroid plexus
Blood-brain barrier

22. Spinal Cord
Blood-brain barrier- protection for the brain against undesirable blood substances

23. Peripheral Nervous System
Cranial nerves
12 pairs
Emerge bilaterally from base of the skull
Spinal nerves
31 pairs
Emerge bilaterally from the spinal cord

24. Spinal Nerves
There is a pair of spinal nerves at the level of each vertebrae for a total of 31 pairs
Spinal nerves are formed by the combination of the ventral and dorsal roots of the spinal cord
Spinal nerves are named for the region from which they arise

25. Additional Word Parts – Roots
Myelin/o myelin sheath

26. Roots
Cerebell/o cerebellum

27. Roots
Cerebr/o brain

28. Roots
Cortic/o cortex; outer covering

29. Roots
Dur/o dura mater

30. Prefixes
Pachy- thick
Pachymeninx- dura mater

31. Roots
Encephal/o -brain
Encephalitis-inflammation of the brain

32. Roots Magnet/o-magnet
Magnetic Resonance Imaging (MRI)-produces picture of brain using magnetic waves

33. Roots
Hydr/o water
Hydrocephalus-accumulation of fluid in the brain

34. Roots Ventricul/o- ventricles
Ventricles-hollow cavities inside the brain

35. Roots Vertricul/o- ventricles
Ventriculostomy-new opening in the ventricles; for treating hydrocephalus

36. Suffixes -oma -tumor Hematoma-accumulation of blood in a space
Epidural hematoma-blood in the epidural space

37. Suffixes -oma -tumor Hematoma-accumulation of blood in a space
Subdural hematoma-blood in the subdural space

38. Types of Brain Hematoma

39. THANK YOU!