What causes cross bridge detachment?
(d) A new molecule of ATP attaches to the myosin head, causing the cross-bridge to detach.
What is a critical event that occurs at the neuromuscular junction?
Which of the following statements describes a critical event that occurs at the neuromuscular junction? Acetylcholine is released by axon terminals of the motor neuron. Action potentials travel the length of the axons of motor neurons to the axon terminals.
What causes calcium to be released from the sarcoplasmic reticulum?
When the muscle is stimulated, calcium ions are released from its store inside the sarcoplasmic reticulum, into the sarcoplasm (muscle ). Stimulation of the muscle fibre, causes a wave of depolarisation to pass down the t-tubule, and the SR to release calcium ions into the sarcoplasm.
Which of the following occurs to skeletal muscle as a result of acetylcholine released at the neuromuscular junction?
At the neuromuscular junction, the nerve fiber is able to transmit a signal to the muscle fiber by releasing ACh (and other substances), causing muscle contraction.
What happens when actin and myosin interact?
The actin–myosin interaction produces two types of movements: force generation between actin filaments leading to contractions, such as in muscle contraction, cell motility, and cytokinesis; and transport of subcellular organelles and macromolecular complexes by myosin motors along actin filaments.
What are the three components of a neuromuscular junction?
Physiological Anatomy of Neuromuscular Junction For convenience and understanding, the structure of NMJ can be divided into three main parts: a presynaptic part (nerve terminal), the postsynaptic part (motor endplate), and an area between the nerve terminal and motor endplate (synaptic cleft).
What are the steps of neuromuscular transmission?
Neuromuscular transmission is dependent on a coordinated mechanism involving (1) synthesis, storage, and release of acetylcholine from the presynaptic motor nerve endings at the neuromuscular junction; (2) binding of acetylcholine to nicotinic receptors on the postsynaptic region of the muscle membrane, with consequent …
What neurotransmitter is released at the neuromuscular junction?
Acetylcholine (ACh) is the principal neurotransmitter at the vertebrate neuromuscular junction (NMJ), however since the discovery that motoneurons and presynaptic terminals of rodent endplates from the hindlimb muscles extensor digitorum longus (EDL) and soleus are positive for glutamate labelling [1,2], it has been …
What causes the Powerstroke?
The power stroke occurs when ATP is hydrolyzed to ADP and phosphate. The power stroke occurs when ADP and phosphate dissociate from the myosin head. The power stroke occurs when ADP and phosphate dissociate from the actin active site.
What does acetylcholine do at the neuromuscular junction?
In the somatic nervous system, acetylcholine is used at the neuromuscular junctions, triggering the firing of motor neurons and affecting voluntary movements.
What prevents acetylcholine from accumulating in the neuromuscular junction?
Botulinum toxin prevents ACh from being released into the synaptic cleft.
What triggers the interaction between myosin and actin in muscle?
When calcium ions are added, they combine with troponin, inhibition is released, actin and myosin interact, and ATP is broken down. In smooth muscles, Ca2+ activates an enzyme (kinase) that catalyzes the transfer of phosphate from ATP to myosin, and the phosphorylated form is then activated by actin.