1. Lecture 10: Chapter 14 The Brain and Cranial Nerves Pages : 451 - 494
Lecturer: Dr. Barjis
Room P313 /P307
Phone: (718)

2. Learning Objectives
Name the major regions of the brain and describe their functions.
Discuss the formation, circulation and functions of the CSF.
List the main components of the medulla oblongata, the pons, the cerebellum, the mesencephalon, the diencephalon, and the limbic system and specify their functions.

3. Learning Objectives
Identify the major anatomical subdivisions of the cerebrum.
Locate the motor, sensory and association areas of the cerebral cortex and discuss their functions.
Describe representative examples of cranial reflexes.

4. An Introduction to the Organization of the Brain
Major regions and landmarks
Six regions in the adult brain
Cerebrum
Diencephalon
Mesencephalon
Pons
Cerebellum
Medulla oblongata
Brain contains extensive areas of neural cortex
Layer of gray matter on the surface of the cerebellum and cerebrum

5. The Adult Brain

6. The Adult Brain

7. The Adult Brain

8. An Introduction to Brain Functions

9. Embryology of the brain
Brain forms from three swellings at the tip of the developing neural tube
Prosencephalon
Forms the telencephalon and eventually the cerebrum and diencephalon
Telecephalon will become cerebrum
Mesencephalon
Mesencephalon will become midbrain
Rhombencephalon
Forms the metencephalon (cerebellum and pons) and myelencephalon (medulla oblongata)

10. Ventricles of the brain
Central passageway of the brain enlarges to form ventricles (cavity)
Contain cerebrospinal fluid (CSF)

11. Ventricles of the Brain
Animation: Brain Dissections (see tutorial)

12. Protection and Support of the Brain
The cranial meninges
Continuous with the three layers of the spinal cord
Folds of dura mater help stabilize the position of the brain
Falx cerebri
Tentorium cerebelli
Falx cerebelli

13. The Relationship among the Brain, Cranium, and Meninges

14. Cerebrospinal fluid (CSF)
CSF cushions delicate neural structures
Supports the brain
Transports nutrients, chemical messengers, and waste products
Pathway of CSF
Produced at the Choroid plexus,
Travels through the lateral and medial apertures to the subarachnoid space,
Diffuses across the arachnoid granulations into the superior sagittal sinus

15. The Circulation of Cerebrospinal Fluid

16. Blood supply to the brain
Blood brain barrier isolates neural tissue from general circulation
Incomplete barrier in areas
Parts of the hypothalamus
Pituitary gland
Pineal gland
Choroid plexus

17. Medulla oblongata Connects the brain with the spinal cord
Contains relay stations and reflex centers
Olivary nuclei – relay impulses from proprioceptor (receptors monitoring joint and muscle position) to cerebellum.
Cardiovascular and respiratory rhythmicity centers
Other nuclei in the medulla control reflexes such as vomiting, coughing, sneezing, blood pressure.
Reticular formation begins in the medulla oblongata and extends into more superior portions of the brainstem

18. The Diencephalon and Brain Stem

19. The Diencephalon and Brain Stem

20. The Medulla Oblongata and Pons

21. The Medulla Oblongata and Pons

22. The pons The pons contains
Sensory and motor nuclei for four cranial nerves
Nuclei that help control respiration
Connects part of the brain with one another:
Nuclei and tracts linking the cerebellum with the brain stem, cerebrum and spinal cord
Connections are provided by bundles of axons (tracts).
Ascending, descending and transverse tracts

23. The Medulla Oblongata and Pons

24. The Medulla Oblongata and Pons

25. The cerebellum Adjusts postural muscles and tunes on-going movements
Cerebellar hemispheres
Anterior and posterior lobes – govern subconscious aspects of skeletal muscle.
Vermis – the central area
Flocculonodular lobe – contributes to equilibrium and balance.
Superior, middle and inferior cerebellar peduncles link cerebellum with brain stem, diencephalon, cerebrum, and spinal cord
Interconnects the two cerebellar hemispheres

26. The Cerebellum

27. The Cerebellum

28. The mesencephalon
The tectum (roof) contains the corpora quadrigemina (four rounded elevations)
Two Superior - they serve as a reflex centers for some visual activities.
Two inferior colliculi – are part of auditory pathway
The mesencephalon contains many nuclei
Red nucleus
Substantia nigra
Cerebral peduncles
RAS (Reticular Activating System) headquarters

29. The Mesencephalon

30. The diencephalon is composed of
Epithalamus
Hypothalamus
Thalamus

31. The thalamus Final relay point for ascending sensory information
Coordinates the activities of the cerebral cortex and basal nuclei

32. The Thalamus

33. The hypothalamus
Controls somatic motor activities at the subconscious level
Controls autonomic function
Coordinates activities of the endocrine and nervous systems
Secretes hormones
Produces emotions and behavioral drives
Coordinates voluntary and autonomic functions
Regulates body temperature
Coordinates circadian cycles of activity

34. The Hypothalamus in Sagittal Section

35. The Hypothalamus in Sagittal Section

36. The limbic system or motivational system includes
Amygdaloid body
Cingulated gyrus
Parahippocampal gyrus
Hippocampus
Fornix
Functions of the limbic system:
emotions and behavioral drives
linking conscious intellectual functions of cortex with unconscious and autonomic functions
Facilitate memory storage and retrival

37. The Limbic System

38. The Brain in Section

39. The Brain in Section

40. The cerebral The cerebral cortex
Surface contains gyri and sulci or fissures
Longitudinal fissure separates two cerebral hemispheres
Central sulcus separates frontal and parietal lobes
Temporal and occipital lobes also bounded by sulci

41. White matter of the cerebrum
Contains association fibers
Commissural fibers
Projection fibers

42. The White Matter of the Cerebrum

43. The basal nuclei Caudate nucleus Globus pallidus Putamen
Control muscle tone and coordinate learned movement patterns

44. Motor and sensory areas of the cortex
Primary motor cortex of the precentral gyrus directs voluntary movements
Primary sensory cortex of the postcentral gyrus receives somatic sensory information
Touch
Pressure
Pain
Taste
Temperature

45. The Cerebral Hemispheres
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46. Association areas
Control our ability to understand sensory information and coordinate a response
Somatic sensory association area
Visual association area
Somatic motor association area

47. general interpretive and speech areas
General interpretive area
Receives information from all sensory areas
Present only in left hemisphere
Speech center
Regulates patterns of breathing and vocalization

48. cortex functions and hemispheric differences
Prefrontal cortex
Coordinates information from secondary and special association areas
Performs abstract intellectual functions
Hemispheric differences
Left hemisphere typically contains general interpretive and speech centers and is responsible for language based skills
Right hemisphere is typically responsible for spatial relationships and analyses

49. Hemispheric Lateralization
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50. Electroencephalogram (EEG)
Measures brain activity
Alpha waves = healthy resting adult
Beta waves = concentrating adult
Theta waves = normal children
Delta waves = normal during sleep

51. Brain Waves
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52. Focus: Cranial Nerves 12 pairs of cranial nerves
Each attaches to the ventrolateral surface of the brainstem near the associated sensory or motor nuclei

53. Origins of the Cranial Nerves
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54. Origins of the Cranial Nerves
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55. Origins of the Cranial Nerves
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56. Olfactory nerves (I)
Carry sensory information responsible for the sense of smell
Synapse within the olfactory bulb

57. The Olfactory Nerve
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58. cranial nerves II, III, IV
Optic nerves (II)
Carry visual information from special sensory receptors in the eyes
Occulomotor nerves (III)
Primary source of innervation for 4 of the extraocular muscles
Trochlear nerves (IV)
Innervate the superior oblique muscles

59. Cranial Nerves Controlling the Extra-ocular Muscles
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60. cranial nerves V, VI, VII Trigeminal nerves (V)
Missed nerves with ophthalmic, maxillary and mandibular branches
Abducens nerve (VI)
Innervates the lateral rectus muscles
Facial nerves (VII)
Mixed nerves that control muscles of the face and scalp
Provide pressure sensations over the face
Receive taste information from the tongue

61. The Trigeminal Nerve
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62. The Facial Nerve
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63. cranial nerves VIII, IX Vestibulocochlear nerves (VIII)
Vestibular branch monitors balance, position and movement
Cochlear branch monitors hearing
Glossopharyngeal nerves (IX)
Mixed nerves that innervate the tongue and pharynx
Control the action of swallowing

64. cranial nerves X Vagus nerves (X) Mixed nerves
Vital to the autonomic control of visceral function

65. The Vestibulocochlear Nerve
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66. The Glossopharyngeal Nerve
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67. The Vagus Nerve
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68. cranial nerves XI, XII Accessory nerves (XI) Internal branches
Innervate voluntary swallowing muscles of the soft palate and pharynx
External branches
Control muscles associates with the pectoral girdle
Hypoglossal nerves (XII)
Provide voluntary motor control over tongue movement

69. The Accessory and Hypoglossal Nerve
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70. Cranial reflexes
Involve sensory and motor fibers of cranial nerves

71. You should now be familiar with:
The major regions of the brain and their functions.
The formation, circulation and functions of the CSF.
The main components of the medulla oblongata, the pons, the cerebellum, the mesencephalon, the diencephalon, and the limbic system and their functions.
The major anatomical subdivisions of the cerebrum.
The motor, sensory and association areas of the cerebral cortex.
Representative examples of cranial reflexes.