1. HUMAN ANATOMY Chapter 15 Chapter 15 Lecture The Nervous System:
Fifth Edition
Chapter 15
The Nervous System:
The Brain and Cranial Nerves
Frederic Martini Michael Timmons
Robert Tallitsch
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings

2. Introduction • The brain is far more complex than the spinal cord.
• The brain contains roughly 20 billion neurons.
- Excitatory and inhibitory interactions among the extensively interconnected neuronal pools ensure that the response can vary to meet changing circumstances.

3. Embryology of the Brain
Table Development of the Human Brain

4. Fig
15.1

5. Fig
15.11
White matter Grey matter

6. Ventricles
Fig
4 fluid filled cavities in the brain Lined by ependymal cells
15.2
Contain cerebrospinal fluid

7. Protection and support of the brain
• Bones of the skull
• cranial meninges
• cerebrospinal fluid
• blood-brain barrier

8. Cranial Meninges • Protective layers of the brain & spinal cord
- Provide physical stability and shock absorption
• Outermost
- Dura mater-Tough fibrous layer
• Middle
- Arachnoid
• Innermost
- Pia mater

9. The Cranial Meninges
Figure 15.4a Superior Cut away

10. The Cranial Meninges
Figure 15.3c Midsagittal View

11. • Deep to arachnoid is subarachnoid space
- Network of collagen and elastin fibers (arachnoid trabeculae)
- Contains CSF

12. The Cranial Meninges
Figure 15.4b,c Coronal Section

13. Cerebral Spinal Fluid • Cushions the CNS
• Supports the brain-the brains is floating in the CSF
• Transport nutrient/wastes etc.

14. Choroid plexus • Produces CSF 500 ml/day
• Composed of ependymal cells and
capillaries (CSF is very different from plasma)
• Found in each ventricle
• Floor of lateral ventricles (2)
• Roof of 3rd ventricle
• Roof of 4th ventricle

15. Fig
15.5

16. CSF circulation
Blood supply to the brain is from the internal carotid and vertebral arteries

17. Blood brain barrier • Maintained by astrocytes • Not found in:
- the hypothalamus
- Pineal gland
- Roof of 3rd & 4th ventricles

18. The Cerebrum
Figure 15.8a,b The Cerebral Hemispheres, Superior and Anterior Views

19. The Cerebrum
Figure 15.8c Posterior View
Figure 15.9a Lateral View

20. Functions of the Cerebrum
Table The Cerebral Cortex

21. Motor and Sensory Areas of the Cerebral Cortex
Figure 15.9b Functional Areas of the Cortex

22. Central White Matter of the Brain
Figure 15.10a Lateral View
Figure 15.10b Anterior View

23. Basal Nuclei
Figure 15.11b,c Coronal View

24. The Limbic System
Figure 15.12a Lateral View
Figure 15.12b Close up

25. Sectional View Inside the Brain: The Diencephalon
Figure 15.13a Midsagittal View

26. Sectional View Inside the Brain: The Diencephalon
Figure 15.13b Coronal Section

27. The Diencephalon: Thalamus
Table The Thalamus

29. The Mesencephalon Figure 15.16a Lateral View
Figure 15.16c Posterior View

30. Copora
quadrigemina
Aqueduct of midbrain
Fig or
15.15
Cerebral
peduncles Cerebral aqueduct

31. The Pons
Figure The Pons

32. The Cerebellum
Figure 15.19a Posterior, Superior Surface

33. The Cerebellum
Figure 15.19b Sagittal Section of Cerebellum

34. Fig
15.13

35. The Cranial Nerves • Cranial nerves are components of the
peripheral nervous system that connect to the brain rather than to the spinal cord.
- There are twelve pairs of cranial nerves.
- Cranial nerves are numbered using Roman numerals.
• Each cranial nerve attaches to the brain near the associated sensory or motor nuclei.

36. 1-12 Old
12 pairs of Cranial
nerves
Owls
Fig On
15.21
Tree
Tops Are
Forever
Viewing Green Valleys
And 12
Hills 11

37. The Olfactory Nerve (N I)
• Primary function:
- Special sensory (smell)
• Origin:
- Receptors of olfactory epithelium
Figure The Olfactory Nerve

38. The Olfactory Nerve (N I)
• Passes through:
- Cribriform plate of ethmoid
• Destination:
- Olfactory bulbs
Figure The Olfactory Nerve

39. The Optic Nerve (N II) • Primary function: • Origin: • Passes through:
- Special sensory (vision)
• Origin:
- Retina of eye
• Passes through:
- Optic canal of sphenoid
• Destination:
- Diencephalon by way of the optic chiasm

40. The Optic Nerve (N II)
Figure The Optic Nerve

41. The Oculomotor Nerve (N III)
• Primary function:
- Motor, eye movements
• Origin:
- Mesencephalon
• Passes through:
- Superior orbital fissure of sphenoid

42. The Oculomotor Nerve (N III)
• Destination:
- Somatic motor:
• Superior, inferior, and medial rectus muscles; the inferior oblique muscle; the levator palpebrae superioris muscle
- Visceral motor:
• Intrinsic eye muscles

43. The Oculomotor Nerve (N III)
Figure The Oculomotor Nerve

44. The Trochlear Nerve (N IV)
• Primary function:
- Motor, eye movements
• Origin:
- Mesencephalon
• Passes through:
- Superior orbital fissure of sphenoid
• Destination:
- Superior oblique muscle

45. The Trochlear Nerve (N IV)
Figure The Trochlear Nerve

46. The Trigeminal Nerve (N V)
• Primary function:
- Mixed (sensory and motor)
- Ophthalmic and maxillary branches sensory
- Mandibular branch mixed

47. The Trigeminal Nerve (N V)
• Origin:
- Ophthalmic branch (sensory):
• Orbital structures, nasal cavity, skin of forehead, superior eyelid, eyebrow, and part of the nose
- Maxillary branch (sensory):
• Inferior eyelid, upper lip, gums, and teeth; cheek; nose, palate, and part of the pharynx
- Mandibular branch (mixed):
• Sensory from lower gums, teeth, and lips; palate and tongue (part); motor from motor nuclei of pons

48. The Trigeminal Nerve (N V)
• Passes through:
- Ophthalmic branch through superior orbital fissure
- Maxillary branch through foramen rotundum
- Mandibular branch through foramen ovale
• Destination:
- Ophthalmic, maxillary, and mandibular branches to sensory nuclei in the pons
- Mandibular branch also innervates muscles of mastication

49. The Trigeminal Nerve (N V)
Figure The Trigeminal Nerve

50. The Abducens Nerve (N VI)
• Primary function:
- Motor, eye movements
• Origin:
- Pons
• Passes through:
- Superior orbital fissure of sphenoid
• Destination:
- Lateral rectus muscle

51. The Abducens Nerve (N VI)
Figure The Abducens Nerve

52. The Facial Nerve (N VII)
• Primary function:
- Mixed (sensory and motor)
• Origin:
- Sensory from taste receptors on anterior two- thirds of tongue
- Motor from motor nuclei of pons
• Passes through:
- Internal acoustic meatus of temporal bone, along facial canal to reach stylomastoid foramen

53. The Facial Nerve (N VII)
• Destination:
- Sensory to sensory nuclei of pons
- Somatic motor: muscles of facial expression
- Visceral motor: lacrimal (tear) gland and nasal mucous glands via pterygopalatine ganglion; submandibular and sublingual salivary glands via submandibular ganglion

54. The Facial Nerve (N VII)
Figure The Facial Nerve

55. The Vestibulocochlear Nerve (N VIII)
• Primary function:
- Special sensory:
• Balance and equilibrium (vestibular branch) and hearing (cochlear branch)
• Origin:
- Receptors of the inner ear (vestibule and cochlea)
• Passes through:
- Internal acoustic meatus of the temporal bone

56. The Vestibulocochlear Nerve (N VIII)
• Destination:
- Vestibular and cochlear nuclei of pons and medulla oblongata

57. The Vestibulocochlear Nerve (N VIII)
Figure The Vestibulocochlear Nerve

58. The Glossopharyngeal Nerve (N IX)
• Primary function:
- Mixed (sensory and motor)
• Origin:
- Sensory from posterior one-third of the
tongue, part of the pharynx and palate, the carotid arteries of the neck
- Motor from motor nuclei of medulla oblongata
• Passes through:
- Jugular foramen between occipital and temporal bones

59. The Glossopharyngeal Nerve (N IX)
• Destination:
- Sensory fibers to sensory nuclei of medulla oblongata
- Somatic motor:
• Pharyngeal muscles involved in swallowing
- Visceral motor:
• Parotid salivary gland, after synapsing in the otic ganglion

60. The Glossopharyngeal Nerve (N IX)
Figure The Glossopharyngeal Nerve

61. The Vagus Nerve (N X) • Primary function: • Origin:
- Mixed (sensory and motor)
• Origin:
- Visceral sensory from pharynx (part), auricle, external acoustic meatus, diaphragm, and visceral organs in thoracic and
abdominopelvic cavities
- Visceral motor from motor nuclei in the medulla oblongata

62. The Vagus Nerve (N X) • Passes through: • Destination:
- Jugular foramen between occipital and temporal bones
• Destination:
- Sensory fibers to sensory nuclei and
autonomic centers of medulla oblongata
- Somatic motor to muscles of the palate and pharynx
- Visceral motor to respiratory, cardiovascular, and digestive organs in the thoracic and abdominal cavities

63. The Vagus Nerve (N X)
Figure The Vagus Nerve

64. The Accessory Nerve (N XI)
• Primary function:
- Motor
• Origin:
- Motor nuclei of spinal cord and medulla oblongata
• Passes through:
- Jugular foramen between occipital and temporal bones

65. The Accessory Nerve (N XI)
• Destination:
- Internal branch innervates voluntary muscles of palate, pharynx, and larynx
- External branch controls sternocleidomastoid and trapezius muscles

66. The Accessory Nerve (N XI)
Figure The Accessory Nerve

67. The Hypoglossal Nerve (N XII)
• Primary function:
- Motor, tongue movements
• Origin:
- Motor nuclei of the medulla oblongata
• Passes through:
- Hypoglossal canal of occipital bone
• Destination:
- Muscles of the tongue

68. The Hypoglossal Nerve (N XII)
Figure The Hypoglossal Nerve