Anatomy and Physiology

    Ionising Radiation
    What is the purpose of an intensifying screen?
    It converts x-rays (which have high energies but are invisible) into visible light photons. Because visible light photons have low energy, an x-ray photon can be made to produce lots of them.
    Author: rikazzz Comment
    Cells and Tissues
    Which of the following molecules cannot pass through the plasma membrane?
    These hormones are not lipid soluble and too large to pass through channels.
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    Ionising Radiation
    Conventional radiography – such as a chest x-ray (CXR) – differs from computed tomography (CT) in what respect?
    CT images are unobstructed by the “shadow” of overlying structures.
    Author: rikazzz Comment
    Cardiovascular System
    The pressure inside a working suction bottle is most likely to be:
    Given that atmospheric pressure is about 760 mmHg, for suction to occur, the pressure in the suction bottle must be a “negative” pressure. That is, less than 760.
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    Nervous System
    Which of the following statements is true of neuroglia?
    Neuroglia refers to several types of cells of the nervous system that are not neurones. Some of them form the myelin sheath.
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    Chemistry for Physiology
    A healthy concentration of sodium in the blood is typically 140 mmol/L. How many grams of sodium are there in a litre of blood? (atomic mass of Na = 23)
    The number of moles of a substance is determined by dividing the mass of substance by the mass of 1 mol of substance. One mole of sodium has a mass of 23 g: 140 mmol/L = 0.140 mol/L = mass of Na dissolved in 1 L (in gram) ÷ 23. Hence mass of Na = 23 × 0.14 = 3.22 g/L
    Author: rikazzz Comment
    Cardiovascular System
    What is a normal pressure in the venous system returning blood to the heart?
    35 mmHg is BP at arterial end of capillary, so C is also wrong. 17 mmHg is BP at venous end of capillary, while 35 cmH2O is ~26 mmHg so choice B is too high.
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    Skeleton and Joints
    What is the term “osteon” used for?
    Osteon and Haversian system are synonyms. A Haversian canal (central canal) is at the centre of the Haversian system.
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    Gastrointestinal System
    Where is angiotensinogen produced? In the:
    The liver produces many proteins including this precursor to angiotensin II.
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    Gastrointestinal System
    What is the name given to the process of moving the gut contents along the tract in the right direction?
    Segmentation is “to and fro” movement about the one spot.
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