Saturday, 11 June 2011

Nervous and sensory systems

First listen to the presentation: Nervous and sensory systems

1. Protective layers of the brain
What is the collective name for the protective layers of the brain? What are they each called?
Answer: The Meninges; pia mater; arachnoid mater; dura mater.

2. Fluid in the brain
What fluid is found in brain and spinal column? Where is this found in the brain? State two functions of this fluid.
Answer: Cerebrospinal fluid (CSF); located in the ventricles; protection and chemical stability.

3. The neurone
Name the main features of the neurone.
Answer: cell body; axon; dendrites; axon terminals (could include myelin sheath).

4. The action potential
Explain what happens in an action potential.
Answer: sodium ions flood into the nerve cell; the membrane potential is reversed (becomes positive); the action potential is transmitted along the cell (saltatory conduction); the sodium ions are pumped out and the resting potential is restored.

5. The synapse
What happens at a synapse?
Answer: nerve impulse arrives at pre-synapse; chemical (acetly choline) released into synaptic space; action potential triggered post-synapse; chemical is broken down and reabsorbed .

6. Saltatory conduction
Explain saltatory conduction.
Answer: tales place in myelinated nerves; faster than in unmyelinated nerves; depends on Nodes of Ranvier; action potential 'jumps' from node to node (ie Nodes of Ranvier).

7. Regions of the brain
Name the eight regions of the brain (half mark each).
Answer: frontal; motor cortex; sensory cortex; parietal lobe; temporal lobe; occipital lobe; cerebellum; brain stem.

8. Cranial nerves
What do cranial nerves mainly do?
Answer: eye movement; swallowing; smell; hearing.

9. Divisions of the nervous system
Name the two divisions of the peripheral nervous system and the sub-divisions of the division concerned with involuntary actions.
Answer: somatosensory and autonomic; and the autonomic is divided into the sympathetic and the parasympathetic systems.

10. Special senses
In addition to sight what are the other special senses?
Answer: hearing; touch; taste and smell.

11. The eye
What four structures of the eye does light have to travel through to reach the optic nerve?
Answer: cornea; aqueous humour; lens; vitreous humour.

12.The ear
What are the three bones of the inner ear and what are they called, collectively?
Answer: maleus; incus and stapes; ossicles.

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