Muscles

    Muscles
    With respect to the flexion of the forearm, which of the following statements is correct?
    Antagonist for flexion is the triceps brachii (the origin, not the insertion of the biceps brachii, is on the scapula).
    Author: rikazzz Comment
    Muscles
    All of the following structures are part of a muscle cell except one. Which one?
    Sarcoma refers to a malignant tumour (a cancer) of connective or other non-epithelial tissue (bones, muscles, tendons, cartilage, nerves, fat and blood vessels).
    Author: rikazzz Comment
    Muscles
    What causes the myosin binding site of an actin molecule to be exposed?
    Ca causes a change of shape to the troponin molecule when they attach. This causes troponin to wrench tropomyosin away from its resting position covering the binding site.
    Author: rikazzz Comment
    Muscles
    The muscle known as the “transversus abdominis” is named according to:
    Its location = abdominis; its muscle fibre direction = transversus.
    Author: rikazzz Comment
    Muscles
    What does the term “origin” refer to in the musculoskeletal system?
    Muscles are said to “originate” on the bone that does not move when that muscle contracts and to insert on the bone that does flex or extend when the muscle contracts.
    Author: rikazzz Comment
    Muscles
    Skeletal muscle cells have all of the following characteristics EXCEPT one. Which one?
    Skeletal muscle cells are not branched (but cardiac muscle cells are).
    Author: rikazzz Comment
    Muscles
    What is the protein of thick myofilaments in a skeletal muscle cell?
    Choices A and C are both proteins of thin myofilaments. ACh is a neurotransmitter.
    Author: rikazzz Comment
    Muscles
    Microscopically, muscle fibres contain parallel myofibrils. What are the units joined end to end within a myofibril called?
    Sarcomeres joined end to end, like train carriages, form a myofibril.
    Author: rikazzz Comment
    Muscles
    On which molecule is the energised cross-bridge which produces muscle cell contraction located?
    The myosin molecule has a “cross-bridge”. The actin molecule has the binding site for the cross-bridge which is covered by tropomyosin. Ca binds to troponin in order to move tropomyosin away from the binding site.Energy for Muscle Contraction
    Author: rikazzz Comment
    Muscles
    Which statement below best describes the role of Ca++ in muscle contraction?
    Ca attaches to troponin causing a shape change which shifts the attached tropomyosin away from binding sites of actin.
    Author: rikazzz Comment