Preview

Physiolab 9.0 Exercise 2

Good Essays
Open Document
Open Document
2165 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Physiolab 9.0 Exercise 2
NAME Rachel Brockhuis
LAB TIME/DATE _______________________
Exercise 2
Skeletal Muscle Physiology

The Muscle Twitch and the Latent Period
1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period. Motor unit- single α-motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type
Skeletal muscle fiber- long and narrow cells that often span the entire length of a muscle
Skeletal muscle twitch- an activation of a muscle by firing a motor neuron
Electrical stimulus- the application of an electric current by means of a prosthesis to stimulate and restore partial function to a muscle disabled by neurologic lesions
Latent period-a seemingly inactive period, as that between exposure to an infection and subsequent illness, or that between the instant of stimulation and the beginning of response.
2. What is the role of acetylcholine in a skeletal muscle contraction? Acetylcholine is the chemical signal the nerve sends to the muscle to cause contraction

3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. 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.

4. Describe the three phases of a skeletal muscle twitch.
Latent Phase: During this phase there is no muscle contraction. This phase is the period of time prior to muscle contractions. The latent phase, chemical changes in the cells occur in preparation for muscle contractions.
Contraction Phase: Is the period in which the muscle tension is at it's highest. This is the time where the greatest amount of muscle force is generated. It begins at the end of the latent

You May Also Find These Documents Helpful

  • Better Essays

    It is known that the two pathways, EMC and PMC result in smooth muscle contraction; however, the source of calcium required for contraction is unknown for each pathway. Therefore, this study aimed to investigate whether the use of calcium in EMC and PMC relies on external or…

    • 1666 Words
    • 6 Pages
    Better Essays
  • Satisfactory Essays

    Exercise 2 Physioex

    • 683 Words
    • 3 Pages

    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
  • Satisfactory Essays

    Phys Ex

    • 330 Words
    • 2 Pages

    1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period.…

    • 330 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. During a single twitch of a skeletal muscle You correctly answered: b. maximal force is never achieved. 2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle contraction than a stand-alone twitch. This phenomenon is known as You correctly answered: c. wave summation. 3. Wave summation is achieved by You correctly answered: a. increasing the stimulus frequency (the rate of stimulus delivery to the muscle). 4. Wave summation increases the force produced in the muscle. Another way to increase the force produced by a muscle is to You correctly answered: d. increase the number of activated motor units.…

    • 1052 Words
    • 5 Pages
    Good Essays
  • Good Essays

    Skeletal Muscle Lab

    • 1182 Words
    • 5 Pages

    The Latent Period of time that elapses between the generation of an action potential in a muscle cell and the start of muscle contraction. The length of the latent period was 2.78msec. When we increased the stimulus voltage from 3v to 9v and then to 10v, the latent period remained the same at 2.78msec. Thus, the latent period does not change with different stimulus.…

    • 1182 Words
    • 5 Pages
    Good Essays
  • Powerful Essays

    For a skeletal muscle fiber to contract, a stimulus must be applied to it. The stimulus is delivered by a nerve cell, or neuron. A neuron has a threadlike process called and axon that my run 91 cm or more to a muscle. A bundle of such fibers from man different neurons composes a nerve. A neuron that stimulates muscle tissue is called a motor neuron.…

    • 2235 Words
    • 9 Pages
    Powerful Essays
  • Good Essays

    Skeletal Muscle

    • 602 Words
    • 3 Pages

    Animals have three types of muscles; skeletal, smooth, and cardiac. This lab however is only concerned with skeletal muscle. A special characteristic of skeletal muscle is their ability to contract or shorten via thin (actin) and thick (myosin) filaments (Flanagan,2017). This gives a striated appearance which is a key distinguishing characteristic between other types of muscle (Flanagan,2017). Skeletal muscle is also multinucleated. Skeletal muscle needs plentiful amounts of energy to be able to contract, thus having multiple nucleus in each muscle fiber allows for more mitochondria, where the cell gets its power, which increases the amount of useable energy (Flanagan,2017).…

    • 602 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Muscles Lab Report

    • 1104 Words
    • 5 Pages

    The skeletal muscles are made up of bundles of muscle fibres (which are also known as myofibrils, as can be seen below). Each of the muscle fibres contain many sarcomeres, which is the most basic form of striated muscle tissue- they consist of two long proteins which slide against each other in order to make the muscles move. These two proteins are known as actin and myosin.…

    • 1104 Words
    • 5 Pages
    Good Essays
  • Good Essays

    This explanation of muscle contraction is so important to understanding rigor mortis because it is exactly that. “Rigor mortis is one of the recognizable signs of death that is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff and difficult to move or manipulate”…

    • 525 Words
    • 3 Pages
    Good Essays
  • Good Essays

    2. Match the key terms to the muscles and movements described below. Key: a. prime mover (agonist) 1. 2.…

    • 1678 Words
    • 7 Pages
    Good Essays
  • Satisfactory Essays

    During muscle contraction, groups of muscle fibres trigger a nerve to change the tension in the muscle. The first step in muscle contraction is the brain sending a message to the central nervous system, which in turn sends it to the peripheral nervous system then to the neuromuscular junction. The neurotransmitter, ACh is released into a space between the neuron and the muscle membrane. The action potential is generated altering the sarcolemma. This causes a change in the muscle membrane. As calcium ions are released during the resting phase, the binding sites of the tropomyosin located on the thin actin filaments are covered with troponins. ATP surrounds the thick myosin filament. When contraction happens, calcium ions bind to the troponin,…

    • 227 Words
    • 1 Page
    Satisfactory Essays
  • Good Essays

    Muscle Fiber contractions for our purposes begins with the arrival of action potential (action potential- is an electrical current) at the end of the axon terminal (axon terminal- the swollen distal end of the motor neuron axon). When the action potential reaches the axon terminal the action potential causes the voltage- gated calcium ion channels to open allowing calcium to flow in from extracellular fluid. The presence of calcium in the axon terminal causes synaptic vesicles (synaptic vesicles- small membranous sacs that contain the neurotransmitter acetylcholine also known as ACH) to fuse with the axon terminals axonal membrane. Once fused with the axonal membrane the synaptic vesicles release acetylcholine into the synaptic cleft (synaptic…

    • 282 Words
    • 2 Pages
    Good Essays
  • Powerful Essays

    Mrs Peterkin

    • 3159 Words
    • 13 Pages

    Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period ____…

    • 3159 Words
    • 13 Pages
    Powerful Essays
  • Good Essays

    Muscle Physiology

    • 685 Words
    • 3 Pages

    Muscle Contraction - the shortening of the muscle as a result of tension generated by muscle fibers; -Regulated by the production of calcium ions, stimulated via thermal, chemical, mechanical, and electrical stimuli…

    • 685 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period.…

    • 1359 Words
    • 6 Pages
    Good Essays