← Back to Session

Time Completed: 01:04:43

Final Score 49%

89
91

Questions

  • Q1. Correct
  • Q2. X Incorrect
  • Q3. X Incorrect
  • Q4. Correct
  • Q5. Correct
  • Q6. Correct
  • Q7. X Incorrect
  • Q8. Correct
  • Q9. X Incorrect
  • Q10. X Incorrect
  • Q11. X Incorrect
  • Q12. Correct
  • Q13. Correct
  • Q14. X Incorrect
  • Q15. Correct
  • Q16. Correct
  • Q17. Correct
  • Q18. X Incorrect
  • Q19. Correct
  • Q20. Correct
  • Q21. Correct
  • Q22. Correct
  • Q23. Correct
  • Q24. X Incorrect
  • Q25. X Incorrect
  • Q26. X Incorrect
  • Q27. X Incorrect
  • Q28. Correct
  • Q29. X Incorrect
  • Q30. Correct
  • Q31. X Incorrect
  • Q32. X Incorrect
  • Q33. X Incorrect
  • Q34. X Incorrect
  • Q35. X Incorrect
  • Q36. Correct
  • Q37. Correct
  • Q38. X Incorrect
  • Q39. Correct
  • Q40. Correct
  • Q41. Correct
  • Q42. X Incorrect
  • Q43. X Incorrect
  • Q44. Correct
  • Q45. Correct
  • Q46. Correct
  • Q47. Correct
  • Q48. Correct
  • Q49. X Incorrect
  • Q50. Correct
  • Q51. X Incorrect
  • Q52. X Incorrect
  • Q53. X Incorrect
  • Q54. Correct
  • Q55. X Incorrect
  • Q56. Correct
  • Q57. X Incorrect
  • Q58. X Incorrect
  • Q59. Correct
  • Q60. Correct
  • Q61. Correct
  • Q62. Correct
  • Q63. Correct
  • Q64. X Incorrect
  • Q65. Correct
  • Q66. X Incorrect
  • Q67. Correct
  • Q68. X Incorrect
  • Q69. X Incorrect
  • Q70. X Incorrect
  • Q71. X Incorrect
  • Q72. X Incorrect
  • Q73. X Incorrect
  • Q74. X Incorrect
  • Q75. Correct
  • Q76. Correct
  • Q77. X Incorrect
  • Q78. X Incorrect
  • Q79. Correct
  • Q80. Correct
  • Q81. Correct
  • Q82. Correct
  • Q83. Correct
  • Q84. Correct
  • Q85. X Incorrect
  • Q86. X Incorrect
  • Q87. X Incorrect
  • Q88. Correct
  • Q89. X Incorrect
  • Q90. X Incorrect
  • Q91. X Incorrect
  • Q92. Correct
  • Q93. Correct
  • Q94. Correct
  • Q95. Correct
  • Q96. X Incorrect
  • Q97. Correct
  • Q98. Skipped
  • Q99. Correct
  • Q100. X Incorrect
  • Q101. X Incorrect
  • Q102. Correct
  • Q103. X Incorrect
  • Q104. Correct
  • Q105. Correct
  • Q106. X Incorrect
  • Q107. X Incorrect
  • Q108. Correct
  • Q109. Correct
  • Q110. X Incorrect
  • Q111. Correct
  • Q112. X Incorrect
  • Q113. Correct
  • Q114. Correct
  • Q115. Correct
  • Q116. X Incorrect
  • Q117. X Incorrect
  • Q118. X Incorrect
  • Q119. Correct
  • Q120. X Incorrect
  • Q121. Correct
  • Q122. X Incorrect
  • Q123. X Incorrect
  • Q124. X Incorrect
  • Q125. Correct
  • Q126. X Incorrect
  • Q127. X Incorrect
  • Q128. X Incorrect
  • Q129. Correct
  • Q130. X Incorrect
  • Q131. X Incorrect
  • Q132. X Incorrect
  • Q133. X Incorrect
  • Q134. Correct
  • Q135. Correct
  • Q136. X Incorrect
  • Q137. X Incorrect
  • Q138. X Incorrect
  • Q139. Correct
  • Q140. X Incorrect
  • Q141. Correct
  • Q142. X Incorrect
  • Q143. X Incorrect
  • Q144. X Incorrect
  • Q145. Correct
  • Q146. X Incorrect
  • Q147. Correct
  • Q148. X Incorrect
  • Q149. Correct
  • Q150. X Incorrect
  • Q151. Correct
  • Q152. X Incorrect
  • Q153. Correct
  • Q154. X Incorrect
  • Q155. X Incorrect
  • Q156. Correct
  • Q157. Correct
  • Q158. Correct
  • Q159. X Incorrect
  • Q160. Correct
  • Q161. X Incorrect
  • Q162. Correct
  • Q163. Correct
  • Q164. Correct
  • Q165. Correct
  • Q166. X Incorrect
  • Q167. Correct
  • Q168. Correct
  • Q169. X Incorrect
  • Q170. X Incorrect
  • Q171. Correct
  • Q172. X Incorrect
  • Q173. Correct
  • Q174. Correct
  • Q175. X Incorrect
  • Q176. X Incorrect
  • Q177. X Incorrect
  • Q178. Correct
  • Q179. X Incorrect
  • Q180. Correct

Anatomy

Central Nervous System

Question 176 of 180

The substantia nigra is located in which of the following regions of the brain:

Answer:

The midbrain contains the substantia nigra, the largest nucleus of the midbrain; degeneration of this extrapyramidal motor nucleus results in Parkinson's disease.

The brainstem comprises the midbrain, the pons and the medulla. It extends from the tentorial aperture to the level of C1. The medulla passes out of the cranial cavity via the foramen magnum and becomes the spinal cord as C1 roots emerge. The cells of the brainstem are predominantly clumped into nuclei.

By OpenStax [CC BY 4.0 , via Wikimedia Commons

Brainstem. (Image by OpenStax [CC BY 4.0 , via Wikimedia Commons)

Midbrain

The midbrain lies predominantly within the posterior cranial fossa. The aperture in the tentorium cerebelli lies on its dorsal surface.

The midbrain receives its blood supply from the posterior cerebral and superior cerebellar arteries (ex-basilar).

Dopaminergic cells sit within the midbrain within the substantia nigra; loss of dopaminergic neurons is the basis of Parkinson’s disease.

Pons

The pons receives its blood supply from pontine branches of the basilar artery. The pons houses nuclei of the trigeminal nerve, the abducens nerve, the facial nerve and the vestibulocochlear nerve. This knowledge allows prediction of the clinical effects of a pontine haemorrhage:

  • Abducens nucleus (lateral rectus paralysis)
  • Vestibular nuclei (nystagmus, nausea, vomiting, vertigo)
  • Cochlear nuclei (central nerve deafness)
  • Trigeminal nuclei (paralysis of muscles of mastication, jaw deviation, loss of facial sensation)
  • Facial nucleus (facial nerve paralysis and loss of taste sensation from anterior tongue)

Brainstem Nuclei. (Image by Henry Vandyke Carter [Public domain], via Wikimedia Commons)

Medulla

The medulla oblongata is the upward continuation of the spinal cord. It receives its blood supply from the posterior inferior cerebellar arteries and branches of the vertebral and basilar arteries.

Formatio Reticularis of the Medulla Oblongata: 1. Anterior median fissure. 2. Fourth ventricle. 3. Formatio reticularis, with 3’, its internal part (reticularis alba), and 3’’, its external part (reticularis grisea). 4. Raphé. 5. Pyramid. 6. Lemniscus. 7. Inferior olivary nucleus with the two accessory olivary nuclei. 8. Hypoglossal nerve, with 8’, its nucleus of origin. 9. Vagus nerve, with 9’, its nucleus of termination. 10. Lateral dorsal acoustic nucleus. 11. Nucleus ambiguus (nucleus of origin of motor fibers of glossopharyngeal, vagus, and cerebral portion of spinal accessory). 12. Gracile nucleus. 13. Cuneate nucleus. 14. Head of posterior column, with 14’, the lower sensory root of trigeminal nerve. 15. Fasciculus solitarius. 16. Anterior external arcuate fibers, with 16’, the nucleus arcuatus. 17. Nucleus lateralis 18. Nucleus of fasciculus teres. 19. Ligula.

Lateral medullary syndrome results from occlusion of the intracranial portion of the vertebral artery (most commonly) or of the posterior inferior cerebellar artery (PICA). The resultant structures affected are the:

  • Vestibular nuclei (nystagmus, nausea, vomiting, vertigo)
  • Inferior cerebellar peduncle (cerebellar signs)
  • Nucleus ambiguus of glossopharyngeal and vagus nerve (ipsilateral laryngeal, pharyngeal and palatal paralysis with dysarthria, dysphagia, dysphonia)
  • Spinothalamic tracts (contralateral loss of pain and temperature from trunk and limbs)
  • Spinal trigeminal nucleus and tract (ipsilateral loss of pain and temperature from face)
  • Descending sympathetic tract (ipsilateral Horner's syndrome)

Medial medullary syndrome results from occlusion of small perforating branches from the vertebral or proximal basilar artery such as the anterior spinal artery. The resultant structures affected are the:

  • Corticospinal tract (contralateral hemiparesis of trunk and extremities)
  • Medial lemniscus (contralateral loss of proprioception, two-point discrimination and vibration of trunk and limbs)
  • Hypoglossal nerve roots (ipsilateral flaccid paralysis of tongue)

Report A Problem

Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.

Loading Form...

Close
  • Biochemistry
  • Blood Gases
  • Haematology
Biochemistry Normal Value
Sodium 135 – 145 mmol/l
Potassium 3.0 – 4.5 mmol/l
Urea 2.5 – 7.5 mmol/l
Glucose 3.5 – 5.0 mmol/l
Creatinine 35 – 135 μmol/l
Alanine Aminotransferase (ALT) 5 – 35 U/l
Gamma-glutamyl Transferase (GGT) < 65 U/l
Alkaline Phosphatase (ALP) 30 – 135 U/l
Aspartate Aminotransferase (AST) < 40 U/l
Total Protein 60 – 80 g/l
Albumin 35 – 50 g/l
Globulin 2.4 – 3.5 g/dl
Amylase < 70 U/l
Total Bilirubin 3 – 17 μmol/l
Calcium 2.1 – 2.5 mmol/l
Chloride 95 – 105 mmol/l
Phosphate 0.8 – 1.4 mmol/l
Haematology Normal Value
Haemoglobin 11.5 – 16.6 g/dl
White Blood Cells 4.0 – 11.0 x 109/l
Platelets 150 – 450 x 109/l
MCV 80 – 96 fl
MCHC 32 – 36 g/dl
Neutrophils 2.0 – 7.5 x 109/l
Lymphocytes 1.5 – 4.0 x 109/l
Monocytes 0.3 – 1.0 x 109/l
Eosinophils 0.1 – 0.5 x 109/l
Basophils < 0.2 x 109/l
Reticulocytes < 2%
Haematocrit 0.35 – 0.49
Red Cell Distribution Width 11 – 15%
Blood Gases Normal Value
pH 7.35 – 7.45
pO2 11 – 14 kPa
pCO2 4.5 – 6.0 kPa
Base Excess -2 – +2 mmol/l
Bicarbonate 24 – 30 mmol/l
Lactate < 2 mmol/l

Join our Newsletter

Stay updated with free revision resources and exclusive discounts

©2017 - 2024 MRCEM Success