Cerebrum i

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Cerebrum i

  1. 1. CEREBRUM BY PROF. DR. ANSARI (FOR BDS SEMESTER-II STUDENTS ONLY) 1/7/2014 1
  2. 2. CEREBRUM • Is the largest portion of the human brain. • It consists of two cerebral hemispheres, which develop from the embryonic forebrain. • These hemispheres have an outer convoluted layer of gray matter – the cerebral cortex – and an inner layer of white matter. • The two halves are linked by the corpus callosum. • Each hemisphere of the cerebrum is subdivided into four lobes visible from the outside. They are the frontal, parietal, occipital, and temporal lobes. The cerebrum is the integrating center for memory, learning, emotions, and other highly complex 1/7/2014 functions of the central nervous system. 2
  3. 3. 1/7/2014 3
  4. 4. Lobes of the cerebrum 1/7/2014 4
  5. 5. Insula • It is the slow growing and hidden part of cerebrum, submerged by frontal lobe, parietal, & temporal lobes. • The middle cerebral artery emerges out from the lateral sulcus and distributes to the superolateral surface of hemisphere. • The circular sulcus is seen in the insula. 1/7/2014 5
  6. 6. The insula 1/7/2014 6
  7. 7. The surface of cerebral hemisphere • Shows various sulci and gyri, a modification of surface of brain to accommodate large amount of brain tissue within a limited space. • There are three surfaces of cerebral hemispheres. • Superolateral surface, inferior surface and medial surface. 1/7/2014 7
  8. 8. Superolateral surface • The following important gyri and sulci are seen :• Central sulcus, precentral gyrus, post central gyrus. • Frontal lobe has superior frontal gyrus, middle frontal gyrus and inferior frontal gyrus. • The inferior frontal gyrus has cortical centre for speech, Broca’s area. • The lateral sulcus separates the temporal lobe from frontal. 1/7/2014 8
  9. 9. 1/7/2014 9
  10. 10. The temporal lobe • Has three gyri, superior, middle and inferior temporal gyri. • By the help of 2 sulci, superior and inferior temporal sulci, there are three temporal gyri. • The superior temporal gyrus is having the site for hearing, Heschel’s gyrus. 1/7/2014 10
  11. 11. 1/7/2014 11
  12. 12. 1/7/2014 12
  13. 13. The precentral gyrus and post central gyrus 1/7/2014 13
  14. 14. The dominant hemisphere • The left side of the brain controls movement of the right side of the body, and the right side of the brain controls movement of the left half of the body. • For most of us, the left side of the brain is the side necessary for speech. The dominant hemisphere. 1/7/2014 14
  15. 15. 1/7/2014 15
  16. 16. The parietal lobe • It has intraparietal sulcus that divides the parietal lobe into superior parietal lobule and inferior parietal lobule. • Involved in perception of stimuli related to touch, pressure, temperature, and pain. • This region of the brain helps people understand what they see and feel. • It also controls how they understand and process information about the environment around them, such as distance and position of objects. 1/7/2014 16
  17. 17. 1/7/2014 17
  18. 18. Each lobe is associated with:• Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving • Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli • Occipital Lobe- associated with visual processing • Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech 1/7/2014 18
  19. 19. Frontal lobe • You are who you are because of this lobe. • This area determines personality and emotions. • It's also involved in controlling judgment, impulses, sexual behavior, language and movement. 1/7/2014 19
  20. 20. Prefrontal lobotomy • Prefrontal lobotomy was performed to control the aggressive/violent behavior /undesirable behavior of prison inmates/mental asylum patients. • The original lobotomy operation is now rarely performed, if ever, although many countries still accept psychosurgery as a form of radical control of violent behavior (Japan, Australia, Sweden and India are among them). 1/7/2014 20
  21. 21. The visual center is located in occipital lobe • This area determines if you understand what you're looking at. • Damage to the occipital lobe could cause hallucinations, make objects appear larger or smaller then they are or make the colors look abnormal. 1/7/2014 21
  22. 22. The temporal lobe • This region controls your hearing and the ability to recognize words. • It can also affect memory. • Damage to the left side of this lobe can cause problems remembering what people said. • Damage to the right side might stop you from recalling music or pictures. 1/7/2014 22
  23. 23. The medial surface 1/7/2014 23
  24. 24. MEDIAL SURFACE OF CEREBRUM 1/7/2014 24
  25. 25. 1/7/2014 The inferior surface 25
  26. 26. Inferior surface of cerebral hemisphere • It has a large tentorial surface and an orbital surface. • The orbital sulcus is an “H” shaped sulcus, dividing the orbital gyri into, medial orbital gyrus, lateral orbital gyrus, anterior and posterior orbital gyrus. • There is an olfactory sulcus lodging the olfactory tract, medial to it is gyrus rectus. 1/7/2014 26
  27. 27. THE INFERIOR SURFACE 1/7/2014 27
  28. 28. Inferior surface 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Frontal pole Temporal pole Olfactory tract & sulcus Orbital gyri Gyrus rectus Inferior temporal sulcus Inferior temporal gyrus Occipitotemporal sulcus Fusiform gyrus Collateral sulcus Lingual gyrus Uncus Calcarine sulcus 1/7/2014 28
  29. 29. Cranial nerves attachments 1/7/2014 29
  30. 30. Structures in the inter-peduncular fossa 1/7/2014 30
  31. 31. Uncus 1. 2. 3. 4. 5. 6. 7. 8. 9. 1/7/2014 Optic nerve Optic chiasma Optic tract Tuber cinereum Mamillary bodies Anterior perforated substance Olfactory trigone Pons Uncus 31
  32. 32. Uncinate fits are preceded by hallucination of disagreeable odors 1/7/2014 32
  33. 33. Applied anatomy of uncus • In situations of tumor, hemorrhage, or edema, increased volume of the temporal lobe can push the uncus against the brainstem and its corresponding cranial nerves. • If the uncus becomes herniated the structure lying just medial to it, cranial nerve III, can become compressed. • This causes problems associated with a non-functional or problematic CNIII - pupil on ipsilateral side fails to constrict to light, etc. • Brainstem damage is typically ipsilateral to the herniation 1/7/2014 33
  34. 34. References • Clinically Oriented Anatomy- Keith Moore – pages 512-519 4th Edition • http://en.wikipedia.org/wiki/Cerebrum • http://webspace.ship.edu/cgboer/genpsycere brum.html • http://serendip.brynmawr.edu/bb/kinser/Stru cture1.html 1/7/2014 34
  35. 35. Sample mcqs • What is the general term given to a tract connecting the two cerebral hemispheres? • A) Commisure • B) Funiculi • C) Column • D) Peduncle • E. Projection fibers 1/7/2014 • Which ventricle is located centrally within the brain, superior to the hypothalamus ? • A. Second • B) Third • C) Fourth • D) Fifth • E) Lateral 35
  36. 36. Sample MCQS Which of the following would be expected following damage to the cortex that lies just in front of the central sulcus? A. Intense hyper sexuality B. Visual hallucinations C. Inability to discriminate tones as low intensities D. Difficulty in reading and writing E. Difficulty in controlling muscles of the body 1/7/2014 Damage to visual association cortex would be expected to produce:A. Problem in recognizing an object by sight B. Difficulty in playing a tune on a piano C. Difficulty in naming an object a person can touch (but not see) D. Problems in naming a song the person knew before sustaining the brain damage E. An inability to recognize a familiar odour 36

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