Neuronal Transmission and Muscle Contraction Using complete sentences, explain t
ID: 220216 • Letter: N
Question
Neuronal Transmission and Muscle ContractionUsing complete sentences, explain the process of neuronal transmission causing muscles to contract. Be complete, concise, and clear in your answer. Your response should be one to two paragraphs (typed or neatly written). Within your discussion, be sure to use the following terms: neuron, action potential, neurotransmitter, acethycholine, neuromuscular junction, muscle cell/fiber, electrical impulse, sarcoplasmic reticulum, calcium ions, actin and myosin filaments, and sliding filament model
Explanation / Answer
When hypothalamus senses the condition motor neuron transfer impulses to muscle. If sufficient amount of neurotransmitter 'acetylcholine' is released from synaptic cleft or neuromuscular junction and binds to the receptor of muscle cell, ligand gated Na+ ion channel of muscle fiber opens up which leads to opening of voltage gated Na+ ion channel. Extracellular sodium ions come inside the cytoplasm of muscle cell and action potential arises. This also triggers the release of stored calcium ion in the sarcoplasmic reticulum and the calcium ion diffuse in muscle fibre because plasma membrane of muscle cell enters within the cytoplasm of sarcoplasmic reticulum in form of t tubules. Muscle contraction is done by actin and myosine but muscle cant contract because myosine head binding region is covered by troponine and tropomyosine. Troponine has three subunits: t subunit binds with tropomyosine, I binds with intermediate subunit ans c subunit binds with calcium. When calcium is released it binds with the tnC which allows the troponine to remove and tropomyosine is pushed towards f actin side. In normal condition ADP is bound with myosine but when myosine head binds with actin, ADP is released and myosine takes a power stroke. Due to this length of light band and heavy band decreases and muscle contract. This is known as sliding filament theory.