Term
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Definition
| A pathological process that damages a nerve resulting in signs and symptoms. |
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Term
| What is a demyelinating neuropathy? |
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Definition
| A pathological state causing damage to Schwann cells or the myelin sheath. |
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Term
| How would a peripheral neuropathy typically present? |
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Definition
| Tingling or numbness of the digits, weakness of the limbs, hyporeflexia or areflexia, fatigue, and abnormal sensations. |
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Term
| Name one example of an acute demyelinating neuropathy and one example of a chronic demyelinating neuropathy. |
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Definition
Acute: Guillian Barre Syndrome.
Chronic: Chronic inflammatory demyelinating polyneuropathy (CIDP). |
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Term
| How does Guillian Barre typically first present? |
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Definition
| Sock and glove neuropathy |
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Term
| Which minor infection is a common precursor of Guillian Barre? |
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Definition
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Term
| How would you diagnose Guillian Barre? |
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Definition
| Nerve conduction studies, lumbar puncture and electromyography. |
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Term
| What is axonal degeneration? |
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Definition
| The destruction/death of an entire axon, if the cell body is destroyed the axon cannot be regenerated. An axon in the central nervous system cannot undergo regeneration where as an axon in the peripheral nervous system with an intact cell body can. |
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Term
| What is Walleriian Degeneration? |
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Definition
| The degeneration of nerve fibres distal to axon separation from the cell body. |
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Term
| Name 3 symptoms of axonal degeneration |
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Definition
| Tingling, burning, weakness, numbness, or as a loss of motor function |
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Term
| What may cause axonal degeneration? |
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Definition
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Term
| Name 3 causes of axonal degeneration |
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Definition
| Diabetes, alcoholism, genetic conditions e.g Charcot-Marie-Tooth or leprosy. |
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Term
| What is Charcot-Marie-Tooth? |
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Definition
| A genetic disorder with underlying gene mutations which encode proteins in different locations (myelin, Schwann cells and axons) with different functions but share the common final pathway of axonal degeneration. |
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Term
| What is a mononeuropathy? |
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Definition
| Nerve damage involving a single nerve branch by a local cause eg. trauma or compression (carpal tunnel). |
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Term
| Whats is Mononeuropathy Multiplex? |
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Definition
| Nerve damage involving at least one or more nerve trunks, usually assymetric eg. diabetes, leprosy, vasculitis. |
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Term
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Definition
| Nerve damage involving multiple nerve trunks, symmetrical and usually begins distally eg. guillian barre sock and glove. |
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Term
| Name the motor signs of nerve dysfunction |
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Definition
| Weakness, wasting, fasiculations and areflexia. |
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Term
| Name the sensory signs of nerve dysfunction |
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Definition
| Numbness, burning, ataxia, allodynia, reduced proprioception and areflexia. |
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Term
| What type of nerve damage would a compression injury cause? |
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Definition
| Mainly demyelination but may cause distal axonal degeneration. |
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Term
| Name a common example of a nerve compression condition |
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Definition
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Term
| How would you treat guillian barre? |
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Definition
| IV Ig (slows advance and shortens duration) and plasma exchange (removes pathogenic antibodies). Patients may also require ventilation. |
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Term
| At rest, the neuronal cell is polarised, what is the potential difference in voltage? |
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Definition
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Term
| How is the electrical gradient maintained? |
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Definition
| Active transport of K+/Na+ requiring ATP |
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Term
| What are ligand gated channels? |
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Definition
| Channels allowing the movement of Ions in response to the binding of a ligand. |
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Term
| What are voltage gated channels? |
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Definition
| Channels alloing the movement of Ions in response to a change in membrane potential, normally non specific Ion movement. |
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Term
| In an action potential what happens in the initiation phase? |
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Definition
| Na+ Ligand Gated Channels open after binding of excitatory neurotransmitter, Na+ floods in. |
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Term
| In an action potential what happens in the rising phase? |
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Definition
| Threshold reached (~65mv) due to ligand mediated Na+ influence, Na+ voltage Gated channels open – Na+ floods in.. |
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Term
| In an action potential what happens in the falling phase? |
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Definition
| K+ Voltage Gated Channels Open initiated by reaching threshold with a delay, K+ floods out, begins to restore resting potential |
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Term
| Describe three steps of synaptic transmission. |
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Definition
1.Pre synaptic Ca2+ Voltage Gated Channels Open and Ca2+ floods in.
2.Ca2+ triggers vesicles to release neurotransmitters by binding to presynaptic membrane.
3.Neurotransmitter binds with post-synaptic Na+ ligand gated channels. Na+ floods in to post synaptic membrane and threshold potential is reached. |
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Term
| Name 3 excitatory neurotransmitters and their function |
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Definition
Noadrenaline- sympathetic system and recycled back into presynaptic membrane.
Adrenaline- acts as a noradrenaline agonsit.
Acetylcholine- post ganglionic parasympathetic system and motor end plate, broken down in cleft by cholinesterase. |
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Term
| How do inhibitory neurotransmitters work? |
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Definition
| Hyperpolarisation of the post synaptic neurone. |
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Term
| Name an anesthetic which works by blocking sodium channels. |
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Definition
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Term
| Name an anti-colvusant using sodium channels |
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Definition
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