nerve impulses AO4

Question 1

how is a nerve impulse transmitted across the synapse?

Answer 1

• action potential arrives
• calcium channels open, calcium ions enter
• vesicles diffuse to the pre-synaptic membrane
• the neurotransmitters are released into the synaptic cleft
• acetylecholine (neurotransmitters) bind to the receptors
• sodium channels open, sodium ions enter and diffuse
• depolarisation of post-synaptic neuron
• enzymes are released, break down the neurotransmitters sending them back
• new action potential is sent
• cycle starts again

Question 2

name the different types of neurotransmitters and what a lack of them can cause.

Answer 2

• acetylecholine -Alzheimer
• dopamine - Parkinson’s
• serotonin - Depression

Question 3

Symptoms of Alzheimer’s

Answer 3

early signs:
- forget about recent conversations or events
- misplace items
- forget the names of places and objects
Middle signs:
- obsessive, repetitive or impulsive behavior
- delusions (believing things that are untrue) or feeling paranoid and suspicious about carers or family members
- problems with speech or language
- disturbed sleep
Final stage:
- difficulty eating and swallowing (dysphagia)
- difficulty changing position or moving around without assistance
- weight loss – sometimes severe

Question 4

Symptoms of Parkinson’s

Answer 4

• tremor
• slow movement
• balance problems
• nerve pain

Question 5

Symptom’s of Depression

Answer 5

psychological:
- low self-esteem 
- feel helpless/hopeless 
- feeling sad and irritable all the time
Physical:
- lack of energy
- change in appetite 
- change in menstrual cycle 
- disturbed sleep

Question 6

how do drugs help treat diseases such as Parkinson’s, Alzheimer’s and Depression to reduce symtoms?

Answer 6

For Alzheimer’s- stops acetylechloine from breaking the neurotransmitter down, acetylecholine builds up in synapse.