Biology

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33 Questions - Developed by: V - Developed on: - 126 taken

  • 1
    - An individual action potential of the muscle cell evokes short lasting contraction – “single muscle twitch“
     True
     False
  • 2
    - A temporal summation of the muscle contraction always results in its isotonic contraction
     True
     False
  • 3
    - A recruitment of additional motor units results in a strengthening of muscle contraction
     True
     False
  • 4
    - A lower frequency of the skeleton muscle stimulation results in a “wave“ tetanus, the higher frequency of stimulation results in a “smooth“ tetanus
     True
     False
  • 5
    - A superposition and summation of the skeleton muscle are produced by two stimuli, which follow each other
     True
     False
  • 6
    - Muscle cells respond to stimulation by action potentials
     True
     False
  • 7
    - Action potentials of the muscle cell activate biochemical processes leading to the muscle contraction
     True
     False
  • 8
    - A myofibril contains contractile proteins actin and troponin
     True
     False
  • 9
    - A depolarization (action potentials) of the muscle cell releases the Ca2+
     True
     False
  • 10
    - Ca2+ being required for the muscle contraction, is stored within the sarcoplasmic reticulum and T tubular system
     True
     False
  • 11
    - Ca2+ is actively transported back to the sarcoplasmatic reticulum and T tubular system by Ca2+ pump
     True
     False
  • 12
    - The sarcoplasmic reticulum and T tubular system release Ca2+ only after hyperpolarization of these structures
     True
     False
  • 13
    - ATP molecules are required for Actin and Troponin molecules to „wedge“ into each other (contraction)
     True
     False
  • 14
    - Generally Ca2+ are required for contraction of the muscle cell
     True
     False
  • 15
    - Ca2+ is an activator of the muscle contraction because its interaction with Troponin C.
     True
     False
  • 16
    - The termination of the muscle contraction is provided by a depletion of ATP
     True
     False
  • 17
    - The motor unit of the skeletal muscle is determined by a number of myofibrils being supplied by one motoneurone
     True
     False
  • 18
    - During the skeletal muscle contraction the „heads“ of the troponin molecules shift the actin filaments
     True
     False
  • 19
    - The heart muscle is not cross stripped
     True
     False
  • 20
    - A smooth muscle is not stripped, its contraction is not intentional, but it is slower and longer lasting, comparing with the skeletal muscle
     True
     False
  • 21
    - The cardiac muscle is not controlled voluntarily, but skeletal and smooth muscles are under the voluntary control
     True
     False
  • 22
    - Refractory periods of the skeletal and cardiac muscles are short
     True
     False
  • 23
    - The cells of cardiac muscle are jointed with intercalar discs, which enhance a synchronization and speed of the heart contraction
     True
     False
  • 24
    - The skeletal and smooth muscles are primarily controlled by the nerve system, but neural control does not participate on the function of the cardiac muscle
     True
     False
  • 25
    - The cardiac and skeletal muscles are similar each other because they content of Intercalar discs
     True
     False
  • 26
    - The cells of smooth muscles are jointed with the „gap junction“ type of interconnections, which allows spreading of the action potentials and spreading of contraction from one cell to another
     True
     False
  • 27
    - The contraction of the heart requires a rapid increase of Ca2+ concentration in the sarcoplasm
     True
     False
  • 28
    - So called “plateau“ of cardiac action potentials is caused mainly by Ca2+ influx
     True
     False
  • 29
    -(2015) Cardiac and Skeletal muscle are completely out of voluntary control
     True
     False
  • 30
    -(2015) Refractory period for skeletal muscle are short(compared to those for cardiac and smooth muscle)
     True
     False
  • 31
    -(2015) muscle cells respond to stimulation by contraction
     True
     False
  • 32
    -(2015) concentration of Ca2+ is on activator of muscle contraction by means of its interaction with actin(resulting in alteration of conformation of actinmyosin)
     True
     False
  • 33
    -(2015) cells of cardiac muscle are joined with intercalary discs, wich would slow down heart contraction
     True
     False

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