Structure of the mammalian nervous systemEdexcel A-Level Biology B: Subtopic test

1. 1
   A neurologist is teaching trainee nurses about the regions of the brain, using a patient who suffered brain damage in a road accident. The patient can still speak, and can decide to move his arm, but he staggers when walking and cannot touch his nose smoothly with a finger.

   (a)

   Which region of the brain is most likely to have been damaged?

   [1 mark]

   • AMedulla oblongata
   • BCerebellum
   • CHypothalamus
   • DCerebrum

   (b)

   Which region of the brain initiates voluntary movement?

   [1 mark]

   • AHypothalamus
   • BMedulla oblongata
   • CCerebrum
   • DCerebellum

   (c)

   Explain why severe damage to the medulla oblongata would be life-threatening.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A student examines a transverse section through a mammalian spinal cord. A central H-shaped region of tissue contains many neurone cell bodies. It is surrounded by an outer region of paler tissue made of myelinated axons running up and down the cord. A narrow fluid-filled canal runs through the centre. Nerves join the cord at two roots, and the root nearer the back has a swelling (a ganglion) on it.

   (a)

   What is the outer paler region of the section?

   [1 mark]

   • AGrey matter containing cell bodies
   • BGrey matter containing myelinated axons
   • CWhite matter containing many cell bodies
   • DWhite matter containing myelinated axons

   (b)

   The swelling (ganglion) on the root nearer the back contains the cell bodies of which neurones?

   [1 mark]

   • ASensory neurones
   • BMotor neurones
   • CRelay neurones
   • DSympathetic motor neurones

   (c)

   Compare the roles of the dorsal root and the ventral root of a spinal nerve.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A man runs a marathon on a hot day. His heart rate rises from 70 to 160 beats per minute during the race, and his core body temperature rises from 37.0 °C to 38.5 °C. He sweats heavily and loses a large volume of water.

   (a)

   Explain how the hypothalamus helps the runner during the race.

   [3 marks]

   (b)

   Calculate the percentage increase in heart rate during the race. Explain how the autonomic nervous system brings about this increase.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A patient arrives at an emergency department after a fall from a ladder. Examination shows that he has lost both sensation and voluntary movement in his legs, but his breathing, heart rate and digestion are normal. A scan shows damage to the spinal cord in the lower back and no damage to the brain.

   (a)

   Describe the structure of the spinal cord and explain why this patient has lost both sensation and voluntary movement in his legs.

   [6 marks]

   (b)

   Explain why his breathing, heart rate and digestion were unaffected while his leg movement was lost, by comparing the voluntary and autonomic divisions of the peripheral nervous system. Include why the autonomic system has two divisions.

   [6 marks]

   Total for question 4: 12 marks

End of questions