Related Experiment Video

Updated: Aug 18, 2026

Historical View and Physiology Demonstration at the NMJ of the Crayfish Opener Muscle
11:56

Historical View and Physiology Demonstration at the NMJ of the Crayfish Opener Muscle

Published on: November 9, 2009

The presynaptic active zones in three different types of fibres in frog muscle

V Verma

    Proceedings of the Royal Society of London. Series B, Biological Sciences
    |May 22, 1984
    PubMed

    More Related Videos

    Loading a Calcium Dye into Frog Nerve Endings Through the Nerve Stump: Calcium Transient Registration in the Frog Neuromuscular Junction17:05

    Loading a Calcium Dye into Frog Nerve Endings Through the Nerve Stump: Calcium Transient Registration in the Frog Neuromuscular Junction

    Published on: July 8, 2017

    Dissection of Single Skeletal Muscle Fibers for Immunofluorescent and Morphometric Analyses of Whole-Mount Neuromuscular Junctions08:41

    Dissection of Single Skeletal Muscle Fibers for Immunofluorescent and Morphometric Analyses of Whole-Mount Neuromuscular Junctions

    Published on: August 14, 2021

    Related Concept Videos

    Classification of Skeletal Muscle Fibers01:48

    Classification of Skeletal Muscle Fibers

    Skeletal muscles continuously produce ATP to provide the energy that enables muscle contractions. Skeletal muscle fibers can be categorized into three types based on differences in their contraction speed and how they produce ATP, as well as physical differences related to these factors. Most human muscles contain all three muscle fiber types, albeit in varying proportions.
    Slow-Twitch Muscle Fibers
    Slow oxidative, muscle fibers appear red due to large numbers of capillaries and high levels of...
    Neuromuscular Junction And Blockade01:29

    Neuromuscular Junction And Blockade

    The site of chemical communication between a motor neuron and a muscle fiber is called the neuromuscular junction (NMJ). The end of the motor neuron at the NMJ divides into a cluster of synaptic end bulbs. The cytoplasm of these bulbs consists of synaptic vesicles enclosing acetylcholine molecules, the principal neurotransmitter released at the NMJ. The region opposite the synaptic bulb that ends in the muscle fiber is called the motor end plate, which has acetylcholine receptors. Within the...
    The Neuromuscular Junction01:19

    The Neuromuscular Junction

    The nervous system consists of complex motor neuron circuits, including upper motor neurons originating from the cerebral cortex and lower motor neurons starting in the spinal cord, coordinating both voluntary and involuntary movements. Among these, somatic motor neurons activate skeletal muscles and are classified into alpha, beta, and gamma types. Alpha neurons are vital for voluntary movement coordination, while gamma neurons adjust muscle spindle sensitivity, and the function of beta...
    Relaxation of Skeletal Muscles01:29

    Relaxation of Skeletal Muscles

    The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
    When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
    Motor Unit Stimulation01:20

    Motor Unit Stimulation

    When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
    The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
    Types of Skeletal Muscle Fibers01:32

    Types of Skeletal Muscle Fibers

    Skeletal muscles comprise various fibers, each with distinct characteristics and roles in movement and stability. They are mainly categorized into three types — fast-twitch, slow-twitch, and intermediate.
    Fast-twitch fibers
    Fast-twitch fibers, or Type II fibers, are designed for quick, powerful bursts of speed and strength. They reach peak tension within approximately 0.01 seconds following stimulation. Characterized by a large diameter and densely packed myofibrils, these fibers contain...