1. The Brain and Cranial Nerves Chapter 9c

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

3. 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.

4. Human Anatomy, 3rd edition Prentice Hall, © 2001 Human Development - Embryology –First two weeks - neural tube forms –4 th week - anterior end of the neural tube forms the forebrain midbrain hindbrain

5. Human Anatomy, 3rd edition Prentice Hall, © 2001 Embryology – 4 Weeks

6. Human Anatomy, 3rd edition Prentice Hall, © 2001 Embryology – 5 Weeks

7. Human Anatomy, 3rd edition Prentice Hall, © 2001 Embryology – 11 Weeks

8. Human Anatomy, 3rd edition Prentice Hall, © 2001 A Child’s Brain

9. Human Anatomy, 3rd edition Prentice Hall, © 2001 Adult Brain –Forebrain Cerebrum Thalamus & hypothalamus –Midbrain –Hindbrain Cerebellum & pons Medulla oblongata

10. Human Anatomy, 3rd edition Prentice Hall, © 2001 Protections and Coverings –Cranial bones –Cranial meninges Dura mater Arachnoid Pia mater

11. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Ventricles of the Brain –Hollow areas within the brain Connect to spinal canal and space around the brain

12. Human Anatomy, 3rd edition Prentice Hall, © 2001 Ventricles of the Brain

13. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cerebrospinal Fluid –Composition Clear, colorless, watery Contains proteins, glucose, urea, salts Contains white blood cells –Functions “Floats” the brain Medium of transport –Formed by specialized cells along edges of ventricles

14. Human Anatomy, 3rd edition Prentice Hall, © 2001 Circulation of Cerebrospinal Fluid –Cerebrospinal fluid circulates around the brain, down through the ventricles, and into the spinal cord.

15. Human Anatomy, 3rd edition Prentice Hall, © 2001 Problems Associated with CSF –Hydrocephalus –Meningitis –Headaches

16. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hydrocephalus

17. Human Anatomy, 3rd edition Prentice Hall, © 2001 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

18. Human Anatomy, 3rd edition Prentice Hall, © 2001 The Parts of the Brain Forebrain Cerebrum, Hypothalamus, Thalamus

19. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cerebrum – Gray & White Matter –Outer layer Cerebral cortex –Gray matter –Inner portion White matter Cerebral nuclei –Masses of gray matter

20. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cerebral Cortex –Gyri are separated by grooves (sulci) Fissures – deeper grooves –Divided into cerebral hemispheres

21. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cerebral Cortex –Divided into lobes –Well mapped Decision-making, planning, personality Primary motor cortex Primary sensory cortex

22. Human Anatomy, 3rd edition Prentice Hall, © 2001 Homunculus Primary Motor CortexPrimary Sensory Cortex

23. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cerebral Nuclei –Collections of cell bodies (gray matter) –Mostly control the movement of skeletal muscles

24. Human Anatomy, 3rd edition Prentice Hall, © 2001 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

25. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hypothalamus –Location – under thalamus –Structure Clusters of nerve cell bodies –Autonomic centers Infundibulum

26. 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

27. Human Anatomy, 3rd edition Prentice Hall, © 2001 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

28. Human Anatomy, 3rd edition Prentice Hall, © 2001 Epithalamus –Location Above thalamus –Contains the pineal body Secretes melatonin

29. Human Anatomy, 3rd edition Prentice Hall, © 2001 Midbrain

30. Human Anatomy, 3rd edition Prentice Hall, © 2001 Midbrain –Relay station –Tracts of motor and sensory neurons –Contains nuclei Substantia nigra secretes dopamine –Modifies muscle tone & motor activity –Parkinson’s disease

31. Human Anatomy, 3rd edition Prentice Hall, © 2001 Hindbrain Cerebellum, Pons, & Medulla Oblongata

32. Human Anatomy, 3rd edition Prentice Hall, © 2001 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

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

34. Human Anatomy, 3rd edition Prentice Hall, © 2001 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)

35. Human Anatomy, 3rd edition Prentice Hall, © 2001 Medulla Oblongata –Continuation of spinal cord –Functions Maintains wakefulness and alertness Contains reflex centers –Cardiac center, vasomotor center, respiratory rythmicity center –Other nonvital centers

36. Human Anatomy, 3rd edition Prentice Hall, © 2001 Cranial Nerves

37. Human Anatomy, 3rd edition Prentice Hall, © 2001 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