CSGD Quiz 1 2006

1

Which ONE of the following statements regarding the femoral nerve is CORRECT?


  It carries fibres from the anterior divisions of the ventral rami of L 2, 3, 4.

  In the femoral triangle it lies medial to the femoral vessels.

  It is enclosed by the femoral sheath.

  It gives motor supply to the components of quadriceps femoris.

  The saphenous nerve is a cutaneous branch supplying the lateral aspect of leg and foot.

2

Bev presents with loss of vision in her left eye. On examination, her optic nerve head is noticeably pale and atrophied. This is most likely because of a vascular occlusion. A branch of which ONE of the following blood vessels is implicated in her disease?


  The long posterior ciliary artery.

  The short posterior ciliary artery.

  The central retinal artery.

  The lacrimal artery.

  The anterior ciliary artery.

3

Choose the CORRECT statement:


  The principal function of myelin is to provide structural rigidity.

  Myelination increases conduction velocity.

  Large axons (i.e. those with large diameter) have low conduction velocity.

  Myelination increases electrical leakage from the axon.

  Myelination has no known function.

4

Bill has developed a sudden loss of vision in his right eye. Testing of his pupil responses is as follows:
-Pen torch shone into the right eye - no pupil constriction in right eye or left eye.
-Pen torch shone into the left eye - pupil constriction of left and right pupil.
Which ONE of the following statements is CORRECT?


  The parasympathetic innervation to the right pupil must be absent.

  Sympathetic innervation to the right sphincter pupillae muscle is abnormal.

  There is a defect in the sympathetic chain around the superior cervical ganglion on the right side.

  There is a defect in the brain between the right Edinger-Westphal nucleus and right ciliary ganglion.

  A lesion is present within the right optic nerve.

5

Bev has developed the following symptoms over the last week. When she looks into the mirror she notices that her left side of her face droops. She is also sensitive to noise and has a scratchy feeling in her left eye. Which ONE of the following statements is CORRECT?


  Her symptoms can be explained by a lesion affecting the trigeminal nerve.

  Her symptoms can be explained by a lesion affecting the glossopharyngeal nerve

  Her symptoms can be explained by a lesion affecting the facial nerve.

  Her symptoms can be explained by a lesion affecting the vagus nerve

  Her symptoms can be explained by a lesion affecting the brainstem within the midbrain.

6

The following scenario applies to both Q6 and Q7:

An MRI of a patient shows a tumor, extending from about C6 to C8, restricted to the entire right side of the spinal cord. The patient will exhibit which ONE of the following:


  Loss of pain sensation in the right foot.

  Loss of temperature sensation around the right nipple.

  Loss of position sense in the right index finger.

  Loss of fine touch sensation from the left toes.

  Inability to determine surface texture with the left index finger.

7

The patient will exhibit which ONE of the following:


  Lower motor neuron signs in the right trapezius.

  Upper motor neuron signs in the right trapezius.

  Increased reflexes in the right triceps.

  Decreased reflexes in the right triceps.

  Loss of tone in the left gastrocnemius.

8

Which ONE of the following statements regarding analgesics is CORRECT?


  Tolerance to morphine will reduce the analgesic actions of pethidine.

  Codeine is a cyclooxygenase inhibitor that reduces the synthesis of prostaglandins in the spinal cord.

  Codeine will prevent the analgesic actions of paracetamol.

  Aspirin selectively inhibits cyclooxygenase 2 to cause analgesia.

  Tolerance to the analgesic actions of morphine arises due to enhanced renal excretion.

9

Which ONE of the following statements concerning glia is CORRECT?


  Astrocytes secrete collagen fibres and are involved in the formation of glial scars.

  Autoimmune injury to Schwann cells may result in areas of demyelination in the CNS.

  Microglia belong to the mononuclear phagocyte system and are the resident macrophages of the CNS.

  An astrocytoma is a benign tumour of the CNS derived from astrocytes.

  Oligodendrocyte foot processes surround capillaries in the brain.

10

Which ONE of the following statements about the developing nervous system is CORRECT?


  The process of mitosis during neurogenesis occurs in the marginal zone of the neural tube.

  Axonal guidance involves the coordinated action of short and long range cues which are always attractive (positive).

  Cajal-Retzius cells in the marginal zone of the cerebral cortex secrete a molecule called nerve growth factor which is involved in the formation of the cortical layers.

  The cerebral cortex is formed in an "outside - in" order with layer 2 forming before layer 6.

  During the "critical period" in early postnatal life depriving one eye of form vision results in reduction of the width of the ocular dominance column (in layer 4) associated with that eye.