Preview

activity 2

Satisfactory Essays
Open Document
Open Document
1695 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
activity 2
Name: Cassidy Lessig
Activity 1 The Muscle Twitch and the Latent Period
1. 1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period 2. What .is the role of acetylcholine in a skeletal muscle contraction?
Skeletal muscle fiber-Skeletal muscle fibers are the individual cells that are bound together in fascicles. Many fascicles are bound together to make a muscle

Motor unit-A motor unit consists of a motor neuron and all of the muscle fibers in innervates.

Skeletal muscle twitch-A skeletal muscle twitch is a mechanical response to a single action potential.

Electrical stimulus- used to mimic the contractions of skeletal muscles
Latent period-Latent period is the period of time between the generation of an action potential in a muscle cell and the start of muscle contraction.

The role of acetylcholine in a skeletal muscle contraction is to bind specific receptors on the sarcolemma to open sodium channels so calcium ions can be released into the sarcoplasm
2. Describe .the process of excitation-contraction coupling in skeletal muscle fibers
The process of excitation-contraction coupling in skeletal muscle fibers is that the end plate potential triggers a series of events that results in the contraction of a muscle cell. End plate potential is caused by the events that occur at the neuromuscular junction.
3. Describe the three phases of a skeletal muscle twitch. The first phase is the latent period- this is the period of time that elapses between the generations of an action potential in a muscle cell. The second phase is the contraction phase- in this phase, the muscle fibers shorten. The third phase is the relaxation phase- in this phase, the muscle is going back to its original stae of relaxation and it will once again lengthen.
4. Does the duration of the latent period change with different stimulus voltages? How well did the results compare with your prediction?
With different

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Review Chapter 10-12

    • 373 Words
    • 2 Pages

    The unit of muscle structure that is composed of bundles of myofibrils, enclosed within a sarcolemma, and surrounded by a connective tissue covering called endomysium is a…

    • 373 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    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
  • Satisfactory Essays

    Nt1310 Unit 3 Lab Report

    • 405 Words
    • 2 Pages

    The threshold for the second action potential increased as the interval between the stimuli decreased as predicted.…

    • 405 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    6. a) latent phase, ~3 msec, the interval from stimulus application until the muscle begins…

    • 589 Words
    • 3 Pages
    Good Essays
  • Better Essays

    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
  • Good Essays

    Latent Period: The beginning stage of muscle contractions. This stage produces no muscle force, but prepares the cells for oncoming contractions by releasing chemicals to the cells.…

    • 2408 Words
    • 10 Pages
    Good Essays
  • Good Essays

    Human skeletal muscle consists of hundreds of individual cylindrically shaped cells (called fibers or myofibers) bound together by connective tissue. In the body, these muscles are stimulated to contract by somatic motor nerves that carry signals in the form of nerve impulses from the brain or spinal cord…

    • 1538 Words
    • 7 Pages
    Good Essays
  • Satisfactory Essays

    1. Name each phase of a typical muscle twitch, and, on the following line, describe what is happening in each phase.…

    • 377 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Fart

    • 1711 Words
    • 7 Pages

    A shock is sent to thru the muscle, leading into the contraction of the of the muscle…

    • 1711 Words
    • 7 Pages
    Good Essays
  • Good Essays

    Muscle!

    • 609 Words
    • 3 Pages

    5. What do acetylcholine and cholinesterase do? Ach initiates an electrical impulse in the sarcolemma and cholinesterase degrades Ach after it diffuse away from its receptor on the motor end plate…

    • 609 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    Mrs Peterkin

    • 3159 Words
    • 13 Pages

    Describe .the process of excitation-contraction coupling in skeletal muscle fibers.The motor unit meets at the neuromusclular junction, where the axon terminal of a neuron and muscle fiber’s plasma membrane meet, also called the motor…

    • 3159 Words
    • 13 Pages
    Powerful Essays
  • Good Essays

    There are three phases for muscle cell contraction: initiation of action potential in the sarcolemma, excitation-contraction coupling, and contraction, sliding of the myofilaments. ATP and calcium ions are two essential elements for muscle contraction. When ATP attaches to the myosin head, it gets hydrolyzed to ADP and Pi. Calcium ions bind to the troponin molecules and help expose the binding sites of actin filaments to allow for the attachment of the myosin heads. After the sliding of the myofilaments occurs, a new ATP is required to unbind the cross bridge between the actin and myosin filaments.…

    • 458 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle…

    • 782 Words
    • 4 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Sliding Filament Theory

    • 549 Words
    • 3 Pages

    Now to go more in depth. Muscle contractions start when a nerve impulse is initiated. Motor neurons which doesn't make contact with the muscle but leaves a gap In between called a synaptic cleft. When stimulus reaches the synaptic cleft, a chemical is released. This is called a neurotransmitter,the neurotransmitter used in muscle contractions called, acetylcholine ( Ach). The Ach diffuses across the synaptic cleft and makes contact with the sarcolemma (muscle cell membrane).…

    • 549 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Muscles in the Human Body

    • 879 Words
    • 4 Pages

    Skeletal muscle tissue is made up of smaller fibers called myofibrils. These myofibrils are composed of even smaller protein filaments. These filaments can be either thick or thin. The thick filaments are made of the protein myosin, and the thin filaments are made of the protein actin. The arrangement of the myosin and actin gives skeletal muscle its striated (or striped) appearance.…

    • 879 Words
    • 4 Pages
    Good Essays