Question

While fumigating his house for insects, Phil became very nauseous. His vision went blurry as his pupils constricted and he began to have severe muscle spasms throughout his body. He also developed a runny nose and he began to salivate heavily. At the emergency room Phil was given injections of Atropine and Valium.

1. What molecule is cholinesterase inhibiting?
2. What is ACh and where is it found? What is its function at the neuromuscular junction?
3. What is AChE and where is it found? What is its function?
4. What are the steps of excitation?
5. In the contraction cycle, what are the roles of the following components:
   1. calcium
   2. myosin
   3. actin
   4. troponin
   5. tropomyosin
   6. ATP
6. What are the steps of the contraction cycle?
7. What are the steps of relaxation?

Answer 1

Cholinesterase inhibitors are molecules which binds to enzyme acetylcholinesterase and prevents acetylcholinesterase to break down acetylcholine into choline and acetate due to this the levels of acetylcholine increases at the synaptic cleft.

ACh is acetylcholine which is a neurotransmitter. It is found in vesicles present at the terminal end of axon and is released in synaptic cleft from the vesicles when action potential arrives at axon terminal.

At neuromuscular junction, acetylcholine transfers nerve impulses from neurons to the muscles which causes muscles to contract.

AChE is acetylcholinesterase enzyme and it is found at the neuromuscular junction in the synaptic cleft between neurons and muscles.

Function of AChE is to break down acetylcholine into choline and acetate and it terminates the transmission of nerve impulse at synapse.