1. The Central Nervous System

2. Components: Brain and spinal cord Bone: skull/vertebral column
Membranes and fluid

3. Meninges: membranes that surround the CNS
Three Layers:
Dura Mater: outer layer next to bone and continues in vertebral column
Arachnoid mater: middle layer; covers brain/spinal cord
3. Pia mater: inner layer that covers nervous tissue. FX: nourishmenst of nerve

4. Meningitis: inflammation of meninges that is caused by bacteria/virus
Mainly infects children
May cause:
Loss of vision/hearing
Paralysis
Mental Retardation

5. Cerebral Spinal Fluid (CSF): clear, watery substance that brings nutrients and protection to neurons
Fills the subarachnoid space
500 ml secreted daily/absorbed by blood
Absorbs forces which may damage brain

6. Spinal Cord: 31 segments (vertebrae)
Each segment has a pair of spinal nerves
Branch out into body (PNS)
Central canal filled with CSF

7. White vs. Gray Matter
White Matter: neuron tissue with myelinated axons Gray Matter: neuron tissue with unmyelinated axons

8. Spinal Cord Functions Conduct nerve impulse along nerve tracts
Two Nerve Tracts:
Ascending: sensory to brain
Descending: motor impulse to organ/gland
2. Center for spinal reflexes

9. Reflexes: quick, involuntary, predictable reactions
- does not involve the brain
Reflex arc: sensory neuron  interneuron  motor neuron
Ex. Knee-jerk reaction, pain reaction

10. The Brain Primary Functions: Interprets sensory information
Issues motor commands to skeletal muscles
Carries higher mental functions (memory/reasoning)
Coordinates muscle movements
Centers/pathways for regulatory visceral activities

11. Brain Organization:
Cerebrum (frontal, parietal, temporal, occipital lobes)
Cerebellum
Brain Stem – connect brain to spinal stem
Diencephalon
Midbrain
Pons
Medulla oblongata

12. Cerebrum: Largest part of the brain Divided into two primary lobes:
-right and left cerebral hemispheres
Corpus Callosum: nerve fibers for connections and communications between hemispheres

13. Cerebrum Surface Features: Sulcus: shallow grooves
Fissure: deep grooves
Gyrus: elevated ridges

14. Cerebral Cortex: outside of the cerebrum
Gray matter, 2-5mm, white matter beneath
FX:
Motor areas (voluntary):
Sensory areas (interpretation)
Association areas (conscious behavior)

15. 1. Primary Motor Areas: in the frontal lobe
Located in the Post-central and Pre-central gyrus
Brocc’s: controls muscle action of mouth, tongue, larynx
Pgs:

16. 2. Association Areas: higher info processes
- Control memory, reasoning, verbalizing, judgment, emotion, concentration, planning, problem solving

17. Cerebral Lobes and Their FX:
Sensory Function
Motor Function
Assoc. Function
Voluntary muscle
Frontal:
Concentration, planning, judgment, problem solving
Parietal:
Temp., touch, pressure, pain
Understand speech; words to express thought
Temporal:
hearing
Remembering visuals; music
Combining visual images
Occipital:
vision

18. Basal Ganglia Serve as a relay station for motor impulses
Coordinates motor activities
Passes impulses from brain stem to spinal cord
Secretes dopamine
- Gray matter deep in cerebrum

19. Ventricles (409)
Interconnecting cavities deep in cerebral hemispheres and brain stem
Continuous with central canal of spinal cord
Filled with CSF
Creates bouancy for the brain

20. Brain Stem: Region of brain that connects the cerebrum to spinal cord
Four Parts:
Pons
Diencephalon
Mid brain
Medulla oblongata

21. Diencephalon: 3 parts
Thalamus – relay station for incoming sensory inputs
Hypothalamus – maintains homeostasis
Limbic System: produces emotions and modifies behavior; fear, anger, pleasure, sorrow

22. Pons: “bridge” Regulates breathing rhythm
Relays impulses from cerebrum to spinal cord
3 cranial nerves from pons

23. Medulla Oblongata FX: Control hear rate
Vasometer center (dilates/constricts blood vessels)
Regulates breathing with pons

24. Reticular Formation:
FX: consciousness by interconnecting several portions of the brain

25. Sleep: suspension of voluntary body functions and consciousness (partial)
Two Types: determined by electro encephalogram (EEG)

26. 1. Non Rapid Eye Movement (NREM)
Waves are slower; longer wavelength
4 stages (I – IV)
“light” sleep to “deep” sleep

27. 2. Rapid Eye Movement (REM)
“Paradoxical Sleep”
Most important type of sleep
Allows the portions of the brain to rest
Higher oxygen consumption in brain than when awake
Dreaming occurs
Increased body temp., heart rate, respiratory and blood pressure
Muscle inhibition
90 minutes after sleep begins

28. Sleep Importance: 1/3 of our lives is spent asleep
Lack of REM leads to depression and other disorders
Brain works through days events/emotions
Dream: “frustrated desires and attempts to fulfill one’s wishes” – Freud
Alcohol suppresses REM
Sleep requirements change as we age (16 hrs to 7 hrs as adults)
Adults are light sleepers
Daily mediation/prayer increases REM

29. The Peripheral Nervous System
Two Branches
Somatic NS (voluntary nerves)
Autonomic NS (involuntary )
Two Nerve Types
Cranial Nerves (brain)
Spinal Nerves (spinal cord)

30. Cranial Nerves:
12 pairs
All originate from brain stem (except 1st pair)
Designated by number and function (p. 469)

31. 1. Olfactory Nerve (smell)

32. 2. Optic Nerve (sight)

33. 3. Oculomotor Nerve (eye muscle)

34. 4. Trochlear Nerve (eye muscle)

35. 5. Trigeminal Nerve (mouth)

36. 6. Abducens Nerve (eye muscle)

37. 7. Facial Nerve (facial muscle) – 5 branches (pg 471)

38. 8. Vestibulocochlear Nerve (auditory)

39. 9. Glossopharangeal Nerve (tongue/pharynx)

40. 10. Vagus Nerve (neck and chest)

41. 11. Accessory Nerve (soft palate, pharynx)

42. 12. Hypoglossal Nerve (tongue, speaking, chewing/swallowing)

43. Spinal Nerves: - 31 pairs from spinal cord
Each contains 1000s of nerve fibers
Named after the vertebral column

44. Spinal Nerves
C: 8
T: 12
L: 5
S: 5
Co: 1
Total: 31

45. -Very short Nerves
- Divided into dorsal root, ventral root, dorsal ramus, and ventral ramus

46. Cauda Equina: “horse tail”
- the end of the spinal cord
Between L1 and L2
Many nerve roots and rootlets

47. Dermatomes
- Area of skin that has sensory nerve fibers from a particular nerve