Preview

What Is Neuromuscular Junction?

Satisfactory Essays
Open Document
Open Document
170 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
What Is Neuromuscular Junction?
Neuromuscular junction is the site the motor neuron and muscle fiber meet. Nerve impulse gets to the axon terminal of the motor neuron and release acetylcholine. Acetylcholine diffuses across the synaptic cleft and binds to the receptors in the motor end plate and starts a muscle action potential. Acetylcholinesterase in the synaptic cleft destroys ach so another muscle action potential does not arise unless more ach is released from motor neuron. Muscle action potential travelling along transverse tubule opens, calcium release channels in the sarcoplasmic reticulum membrane, which allows calcium ions to overflow into sarcoplasm. Calcium binds to troponin on the thin filament (actin), exposing the binding sites for myosin. Reduction power strokes
Continue Reading
View Writing Issues

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Case Study Muscular Junction
    • 504 Words
    • 3 Pages

    Case Study Muscular Junction

    The Neuromuscular junction uses synapses to connect the muscular system with the muscular system. A nerve impulse is sent from the brain down to the motor neuron by way of the axon. Acetylcholine is released after the vesicles break open. Sodium channels are opened from Acetylcholine that bonds to the Acetylcholine receptors. Depolarization happens when Acetylcholine causes an area of the muscle fiber to become a little more positive when it leaves the nerve and docks on receptors in the muscle membrane. Large amounts of Na+ ions enter the muscle fiber because channels open after depolarization, and an action potential then spreads throughout the muscle fiber. The thick and thin filaments of the muscle fiber can then contract…

    • 504 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Better Essays

    Pig Trachealis Smooth Muscle Pharmomechanical coupling uses Internal Calcium stores whilst Electromechanical coupling uses Extracellular Calcium
    • 1666 Words
    • 6 Pages

    Pig Trachealis Smooth Muscle Pharmomechanical coupling uses Internal Calcium stores whilst Electromechanical coupling uses Extracellular Calcium

    Smooth muscle contraction occurs when calcium is present in the smooth muscle cell and binds onto calmodulin to activate myosin light chain kinase (Wilson et al., 2002). Phosphorylation of myosin light chains result in myosin ATPase activity thus cross-bridge cycling occurs causing the muscle to contract (Horowitz et al., 1996). There are two known models of excitation and contraction in smooth muscle, electromechanical coupling (EMC) and pharmomechanical coupling (PMC) (Droogmans et al., 1997). EMC involves a change in membrane potential as a result of nerve stimulation (Sanders, 2008). Depolarisation causes voltage gated calcium channels to open and contraction occurs. High potassium (K+) concentration causes potassium leak channels to shut down thus no positive charge leaves the cell and the membrane becomes depolarised (Morgan et al., 1981). It is possible to determine if a tissue uses EMC, by depolarising the tissue and seeing if it contracts. Depolarisation of smooth muscle cells through the EMC can be achieved when a K+-depolarisation solution is used as a stimulus, causing calcium release and contraction. On the other hand, PMC does not require a change in membrane potential (Edman, 1962). Rather, drugs mediate smooth muscle contraction, for example acetylcholine (Ach) that bind onto receptors and cause the calcium into the smooth muscle cell causing it to contract (Devine et al., 1972, Sanders, 2008).…

    • 1666 Words
    • 6 Pages
    Better Essays
    Read More
  • Good Essays

    1. a Patient Is Admitted for Electroconvulsive Treatment (Ect). the Physician Orders the Neuromuscular Blocking Agent Metocurine Iodide (Metubine) to Reduce Trauma by Relaxing Skeletal Muscles. Explain the Process of
    • 538 Words
    • 2 Pages

    1. a Patient Is Admitted for Electroconvulsive Treatment (Ect). the Physician Orders the Neuromuscular Blocking Agent Metocurine Iodide (Metubine) to Reduce Trauma by Relaxing Skeletal Muscles. Explain the Process of

    To create a muscle contraction your brain sends a message (nerve impulse) to your muscles via axon extensions. The end of this axon forms a union with a single muscle fiber; this union is called the neuromuscular junction. The axon terminal and the muscle fiber don’t actually touch at this junction; they are attached by a space called the synaptic cleft. (Marieb and Hoehn, 2007) Inside the axons terminal there are small sacs containing the neurotransmitter ACh. When the message reaches the end of the axon it opens Calcium channels and Calcium moves into the extracellular space. Once the Calcium is in this space it causes the ACh filled sacs to fuse with the axons membrane and ACh is released into the synaptic cleft. (Marieb and Hoehn, 2007) This ACh drifts across the cleft and into ACh receptors in the sarcolemma of the muscle fiber. After the sarcolemma receives the ACh, ion channels in the ACh receptors are opened and Sodium and Potassium both pass through them. Sodium then triggers action potential that travels across the sarcolemma and into the T Tubules. Once the AP is in the T tubules it is sensed by receptors and causes the sarcoplasmic reticulum to release Calcium into the muscle fibers cytosol. (Marieb and Hoehn, 2007) This Calcium attaches to the Troponin complex located on the thin filament. When the Calcium attaches it changes the shape of the Troponin complex and the Tropomyosin proteins can no longer block the actin…

    • 538 Words
    • 2 Pages
    Good Essays
    Read More
  • Powerful Essays

    101L Bautista Final Exam Review
    • 2639 Words
    • 14 Pages

    101L Bautista Final Exam Review

    channels to open and allow an action potential to occur in the muscle which is known as an…

    • 2639 Words
    • 14 Pages
    Powerful Essays
    Read More
  • Good Essays

    Muscle Metabolism
    • 464 Words
    • 2 Pages

    Muscle Metabolism

    _disconnecting the myosin head from the binding site on actin at the conclusion of a power stroke_________________…

    • 464 Words
    • 2 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    atp worksheet
    • 347 Words
    • 2 Pages

    atp worksheet

    2.Disconnecting the myosin head from the binding site on actin at the conclusion of a power stroke.…

    • 347 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Good Essays

    Physiolab 9.0 Exercise 2
    • 2165 Words
    • 9 Pages

    Physiolab 9.0 Exercise 2

    ACH is released at the end-plate potential. ACH diffuses into the sarcolemma, attaches to the receptors in the motor end plate and causes a change in the ions permeability that creates graded depolarization of the end-plate potential. Basically, it attaches to the receptors in the motor-end plate and creates the beginning process of triggering muscle contractions.…

    • 2165 Words
    • 9 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Homework 3
    • 830 Words
    • 4 Pages

    Homework 3

    Molecule x blocked the ion channel receptor site so acetylcholine could not attach therefor not allowing the muscle to ultimately contract.…

    • 830 Words
    • 4 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Exercise 2 Activity 1
    • 925 Words
    • 4 Pages

    Exercise 2 Activity 1

    Exercise 2: Skeletal Muscle Physiology: Activity 1: The Muscle Twitch and the Latent Period Lab Report Pre-lab Quiz Results You scored 20% by answering 1 out of 5 questions correctly. 1. Skeletal muscles are connected to bones by Your answer : c. ligaments. Correct answer: b. tendons. 2. Skeletal muscles are composed of hundreds to thousands of individual cells called Your answer : b. myofibrils. Correct answer: c. fibers. 3. The term motor unit refers to Your answer : b. all of the activated muscle fibers within one skeletal muscle. Correct answer: c. one motor neuron and all of the skeletal muscle fibers it innervates. 4. The motor neuron and muscle fiber intersect at what is called You correctly answered: d. the neuromuscular junction. 5. A twitch is Your answer : c. multiple contractile responses to a series of action potentials. Correct answer: a. one contractile response to a single action potential.…

    • 925 Words
    • 4 Pages
    Powerful Essays
    Read More
  • Satisfactory Essays

    Study Guides
    • 557 Words
    • 3 Pages

    Study Guides

    -Understand the neuromuscular junction and the components of the neuromuscular junction (synaptic knob, motor end plate, synaptic cleft)…

    • 557 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Exercise 2 Physioex
    • 683 Words
    • 3 Pages

    Exercise 2 Physioex

    Exercise 2: Skeletal Muscle Physiology: Activity 1: The Muscle Twitch and the Latent Period Lab Report Pre-lab Quiz Results You scored 20% by answering 1 out of 5 questions correctly. 1. Skeletal muscles are connected to bones by Your answer : c. ligaments. Correct answer: b. tendons. 2. Skeletal muscles are composed of hundreds to thousands of individual cells called Your answer : b. myofibrils. Correct answer: c. fibers. 3. The term motor unit refers to Your answer : a. all of the motor neurons that innervate one skeletal muscle. Correct answer: c. one motor neuron and all of the skeletal muscle fibers it innervates. 4. The motor neuron and muscle fiber intersect at what is called Your answer : b. the inhibitory synapse. Correct answer: d. the neuromuscular junction. 5. A twitch is You correctly answered: a. one contractile response to a single action potential.…

    • 683 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Patterns in Ancient History
    • 660 Words
    • 3 Pages

    Patterns in Ancient History

    1. Beginning with an impulse from a motor neuron at the neuromuscular junction, describe the normal sequence of events which lead to muscle…

    • 660 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Good Essays

    Exocytosis and the Neuromuscular Junction
    • 472 Words
    • 2 Pages

    Exocytosis and the Neuromuscular Junction

    Exocytosis is the process in which secretory vesicles are exported out of the cell membrane. These vesicles contain proteins which are then transported to parts outside the cell (Wilfred D. Stein, 2012). Neurotransmitters are released during this process into the synaptic cleft. These transmitters attract other transmitters to muscle membrane infoldings, which are called junction folds (Etherington & Hong, 2011). They diffuse across the break between the nerve and muscle to activate contraction. The progression in which signals are sent from motor neurons to skeletal muscle fibres to warrant movement of muscles is called neuromuscular junction (Etherington & Hong, 2011). Motor neurons, Schwann cells, muscle fibres and kranocytes are all the different cell types that make up the neuromuscular junction. Motor neurons send out axons to skeletal muscles where an action potential is passed along the axons. The axons form a synaptic knob where they send activation signals to muscle fibres (Etherington & Hong, 2011). Muscles are made up of hundreds of muscle fibres that all contract simultaneously when an action potential signal is transmitted by a motor neuron (Etherington & Hong, 2011). Schwann cells and kranocytes cover the nerve terminal. Schwann cells are a form of glial cells and Kranocytes are a cell that synthesizes the extracellular matrix and collagen (Etherington & Hong, 2011).…

    • 472 Words
    • 2 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Phys Ex
    • 330 Words
    • 2 Pages

    Phys Ex

    Ach is released at the neuromuscular jxn, Ach attaches to the receptors on the postsynaptic membrane, which opens the…

    • 330 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Vision and Hearing
    • 1077 Words
    • 5 Pages

    Vision and Hearing

    When a weight is placed on a muscle , the muscle lengthen and the muscle spindles are stretched. The stretching causes of the spindle causes depolarization of the 1a axons endings, this is caused by mechanosensitve ion channels. The 1a axons enter the enter the spinal cord through the dorsal root, from here they branch repeatedly and then form synapsese on both…

    • 1077 Words
    • 5 Pages
    Powerful Essays
    Read More