1. The Brain and Cranial Nerves

2. The Brain –Introduction –Development of brain  Embryology –Anatomy of brain  Parts and functions

3. The Brain

4. Introduction to the Brain –Weighs about 3 lbs. in adults –Structures  Divided into 3 general areas –Functions  Controls the bare necessities of life  Location for primal drives and emotions  Intellectual thought, imagination, perception, interpretation, etc.

5. Human Development –First two weeks – neural tube forms –4 th week - anterior end of the neural tube forms the  forebrain  midbrain  hindbrain

6. Embryology – 3-4 Weeks

7. Embryology – 4 Weeks

8. Embryology – 5 Weeks

9. Embryology – 11 Weeks

10. A Child’s Brain

11. Adult Brain –Forebrain  Cerebrum  Thalamus & hypothalamus –Midbrain –Hindbrain  Cerebellum & pons  Medulla oblongata

12. Adult Brain

13. Protections and Coverings –Cranial bones – strong support –Cranial meninges – shock absorbers  Dura mater  Arachnoid  Pia mater

14. The Cranial Meninges

15. The Ventricles of the Brain –Hollow areas within the brain  Connect to spinal canal and space around the brain –Cerebrospinal fluid circulates around the brain, down through the ventricles, and into the spinal cord.

16. Ventricles of the Brain

18. Cerebrospinal Fluid –Composition  Clear, colorless, watery  Contains proteins, glucose, urea, salts  Contains white blood cells –Functions  “Floats” the brain  Medium of transport

19. Circulation of Cerebrospinal Fluid

20. Problems Associated with CSF –Hydrocephalus –Meningitis –Headaches

21. Hydrocephalus

22. Blood-Brain Barrier –A function of glial cells  Secrete chemicals that maintain the BBB  Absorb materials from blood  Extract materials from brain –Cells of capillaries form tight junctions –Differential rates of passage of certain materials

23. Blood-Brain Barrier

24. The Parts of the Brain Forebrain Cerebrum, Hypothalamus, Thalamus

25. Cerebrum – Gray & White Matter –Outer layer – cerebral cortex  Gray matter –Inner portion  White matter  Masses of gray matter – cerebral nuclei

26. Cerebrum – Gray & White Matter

27. Cerebral Cortex –Gyri are separated by grooves (sulci)  Fissures – deeper grooves –Divided into cerebral hemispheres

28. Gyri & Sulci

29. Cerebral Cortex –Divided into lobes –Well mapped  Decision-making, planning, personality  Primary motor cortex  Primary sensory cortex

30. Cerebral Lobes

31. Homunculus Primary Motor CortexPrimary Sensory Cortex

32. Cerebral Nuclei –Collections of cell bodies (gray matter) –Mostly control the movement of skeletal muscles

33. Cerebral Nuclei

34. Limbic System –Functional unit (not anatomical) –Emotional part of the brain  Feelings of fear, loss, love, rage, etc. –Includes parts of several anatomical structures  Cerebrum  Hypothalamus  Thalamus

35. Limbic System

36. Hypothalamus –Initiates primal drives  Hunger, thirst, sex, rage, etc.  Controls autonomic nervous system –“fight or flight” sympathetic response. –Controls pituitary gland (“master gland” of endocrine system)  Infundibulum (“funnel”) funnels secretions to the pituitary gland

37. Hypothalamus –Location – under thalamus –Structure  Clusters of nerve cell bodies –Autonomic centers  Infundibulum

38. Hypothalamus

39. Thalamus –Functions as a relay station between the body and the cerebral cortex  Inform us of our emotional state  Relay information concerned with motor requirements & actions  Integrate visual and auditory reflexes

40. The Thalamus

41. Thalamus

42. Epithalamus –Location  Above thalamus –Contains the pineal body  Secretes melatonin

43. Midbrain

44. Midbrain –Relay station –Tracts of motor and sensory neurons –Contains nuclei  Substantia nigra secretes dopamine –Modifies muscle tone & motor activity –Parkinson’s disease

45. Midbrain

46. Hindbrain Cerebellum, Pons, & Medulla Oblongata

47. Cerebellum –2 nd largest structure of the brain –Divided into 2 lateral hemispheres –Cortex – gyri & sulci  Gray matter –Interior  White matter –Cerebellar nuclei – deep within white matter  Gray matter

48. Cerebellum –Functions – controls subconscious movements in skeletal muscle  Coordination  Posture  Balance

49. Cerebellum, Pons, Medulla Oblongata

50. Pons –Pons = “bridge”  Connects the spinal cord with the brain and parts of the brain with each other  Consists mostly of white fibers –Functions  Controls respiration rate (with medulla)

51. Medulla Oblongata –Continuation of spinal cord –Functions  Maintains wakefulness and alertness  Contains reflex centers –Cardiac center, vasomotor center, respiratory rythmicity center –Other nonvital centers

52. Medulla Oblongata

53. Cranial Nerves

54. Introduction to Cranial Nerves –12 pairs –Leave the skull through foramina –Types  Mixed  Sensory  Motor –Part of the somatic nervous system –Innervate organs in head, neck and upper thorax

55. The Cranial Nerves