Sarcolema receptors
Acetylcholine is the primary chemical transmitter released at the neuromuscular junction. It binds to acetylcholine receptors on the muscle cell membrane, leading to muscle contraction.
acetylcholine as far as i know is a neurotransmitter that ativates the mscle cells.
Organopesticides will increase the severity of muscle contraction beyond normal conditions. Acetylcholine esterase inhibition will allow a more than normal amount of acetylcholine to bind to receptors.
When acetylcholine does not bind to muscle cells, it prevents the activation of nicotinic acetylcholine receptors at the neuromuscular junction. This failure to activate the receptors inhibits the influx of sodium ions, which is necessary for generating an action potential in the muscle fiber. Consequently, muscle contraction cannot occur, leading to muscle weakness or paralysis. This can happen in various conditions, such as myasthenia gravis or in the presence of certain toxins.
It blocks the nicotinic cholinergic receptors on the muscle that normally bind the acetylcholine released by the motor neuron.
It attaches to its receptor, and binds. Causes another action potential, (calcium released) and it goes to the T-tubule of the Sarcoplasmic reticulum, and attaches to troponin, which moves the tropomyosin, so the myosin and actin and attach, and cause a muscle contraction.
Calcium ions need to bind to the protein troponin in order to initiate muscle contraction.
Acetylcholine is released at the neuromuscular junction and binds to a nicotinic receptor, causing an action potential to fire down the T tubules. The voltage change from this is sensed by the Sarcoplasmic Reticulum which then releases Ca2+ ions into the cytosol. The Ca2+ ions bind to troponin which moves tropomyosin from the active sites of the actin filament. Once the active sites are revealed, myosin quickly forms a cross bridge and begins contraction.
The presence of an enzyme called acetylcholinesterasethat degrades acetylcholine is what prevents an accumulation of the neurotransmitter and sustained muscle contraction. Acetylcholinesterase is an enzyme that can be found within the neuromuscular junction. Thus, when a nerve impulse causes the release of acetylcholine at the neuromuscular junction, there is a critical time in which the neurotransmitter can bind to receptors on the muscle before it is degraded.
The triad in muscle contraction consists of a T-tubule and two terminal cisternae of the sarcoplasmic reticulum. It plays a critical role in muscle excitation-contraction coupling by allowing the action potential to be rapidly transmitted deep into the muscle fiber and triggering the release of calcium ions from the sarcoplasmic reticulum, which are essential for muscle contraction.
synaptic cleft, where neurotransmitters are released by the synaptic terminal and bind to receptors on the muscle fiber to trigger a muscle contraction.
Muscle contraction results