After visiting a country picnic, where Jack had eaten a slice of watermelon from
ID: 3514471 • Letter: A
Question
After visiting a country picnic, where Jack had eaten a slice of watermelon from a local producer, he ell and was taken to the local clinic. According to the clinical signs, of which there were many, he was diagnosed with organophosphate poisoning. It turns out that the watermelon had been sprayed with an insecticide containing the chemical organophosphate a) Using a labelled diagram, outline the sequence of events that occurs at the neuromuscular junction after an action potential is propagated to the axon terminal of a neuron. Use Acetylcholine as the example and include a description of each step up to neurotransmitter binding Provide a general description of each of the mechanisms for neurotransmitter removal after it is used Specifically, how is Acetylcholine removed? Explain what organophosphates are and how they interfere with neurotransmission (3 marks) b) (1.5 marks) (0.5 mark) (1 mark) (2 marks) c) d) Name at least two of the clinical signs manifested by organophosphate poisoning in the autonomic nervous system. Include the receptor type for full marks.Explanation / Answer
Answer A. Organophosphorus poisoning occurs due to excess of acetylcholine at the neuromuscular junction due to blockage of acetylcholinsterase enzyme. Acetylcholinsterase metabolises the acetylcholine. Due to blockage of this enzyme, acetylcholine is accumulated at neuromuscular junction. This causes overstimulation of nicotinic receptor. After the action potential is transmitted to axon terminal, neurotransmitter acetylcholine is released from nerve ending. Acetylcholine then binds to nicotinic receptor present over organs. Acetylcholinsterase enzymes is present in neuromuscular junction to metabolises excess acetylcholine.
Answer B. Acetylcholine is removed from neuromuscular junction by metabolism by acetylcholinsterase,active reuptake by nerve ending of presynaptic neuron,diffusion into surrounding tissues.
Answer C. Organophosphate are the phosphoric acid compounds having ester bond in them. They acts by blocking the acetylcholinsterase enzyme. These are also called as nerve agents. They are present in insecticides and pesticides which are sprayed over fruits and vegetables in order to prevent them from pests and insects.
Answer D. Symptoms of organophosphorus poisoning increased salivation, constricted pupils, diarrhoea vomiting, muscle weakness sweating. All these signs and symptoms are due to overstimulation of nicotinic and muscarinic receptor in autonomic nervous system. Anxiety and headache is due to nicotinic receptor overstimulation and diarrhoea, vomiting is due to muscarinic receptor overstimulation.