neuronal communication

Question 1

explain how the lack of mitochondrial cristae limits ATP production in neurones and suggest how this may impair memory function in the Alzheimers patients.

Answer 1

• no oxidative phosphorylation
• less ATP produced
• not enough ATP for the sodium and potassium pumps
• cant generate and action potential
• affects the memory

Question 2

describe and explain 2 features which affect the speed of conductance of nerve impulse along the motor neuron

Answer 2

• myelination - insulated axon = faster transmission
• thick axon - large surface area for division = faster impulse
• temperature - colder temp = ions have less kinetic energy - decreases the speed of conductance

Question 3

describe how cholinergic synaptic transmission works

Answer 3

• action potential arrives and the pre-synaptic membrane
• calcium ion channels open and ca2+ diffuse in
• cause the vesicles containing Ach to fuse and released by exocytosis
• released into the synaptic cleft
• binds to receptor on sodium ion channels on post-synaptic membrane
• receptors open and sodium ions diffuse in causing depolarisation
• Ach is broken down and recycled by acetylcholinerase

Question 4

give 2 similarities between a cholinergic synapse and neuromuscular junction

Answer 4

• both use Ach as a neurotransmitters
• both can be excitatory
• cholinergic = between 2 neurones , neuromuscular = between a neurone and muscle
• cholinergic can involve sensory/motor/relay neurons whereas neuromuscular junctions use motor neurons only