Anatomy and Physiology

    Cardiovascular System
    Which of the following does limb lead II of a typical electrocardiogram represent?
    This is the best answer. “Lead II” is the voltage measured at the RA position minus the voltage measured at the LL position. “Lead II” is also the projection of the electric dipole vector of the heart on the line RII (in Einthoven’s triangle) from the right arm to the left leg.
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    Cardiovascular System
    In which of the following situations would blood pressure be increased?
    Extracellular volume includes the blood. If its volume increases, that means blood volume increases and this will increase BP.
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    Gastrointestinal System
    One of the functions of the liver is to produce:
    Blood cells are produced in the bone marrow; digestive enzymes are produced in the pancreas and gut wall; the hormones insulin and glucagon are produced by the pancreas.
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    Biomechanics
    What may be said about the measurable quantities which are referred to as vectors?
    These four quantities are all vectors. Vectors need a direction as well as a magnitude. Mass is not a vector.
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    Skeleton and Joints
    Where can red marrow be found in the adult?
    All bone marrow in children is red (actively forming blood cells). It gradually changes to “yellow” with age except for the sites in C. The medullary cavities contain yellow marrow. Red marrow is found mainly in the flat bones, such as the pelvis, sternum, cranium, ribs, vertebrae and scapulae and in the cancellous (“spongy”) material at the proximal epiphyseal ends of long bones such as the femur and humerus.
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    Respiratory System
    Which of the following terms refers to normal, unlaboured breathing?
    Dyspnoea is laboured, difficult breathing, bradypnoea is abnormally slow breathing (<12 bpm for ages 12+), and tachypnoea is abnormally fast breathing (>20 bpm at rest for an adult).
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    Chemistry for Physiology
    Which statement about buffers below is most correct?
    A buffer has two conjugate components, one dealing with acid, while the other destroys base. Their concentration ratio determines the pH of the solution they are in.
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    Chemistry for Physiology
    Given that 1 mol of glucose has a mass of 180 g, how many millimole of glucose does 40 g of glucose contain?
    Number of moles of glucose = 40/180 = 0.222 mol. Number of millimoles = 222.
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    The Physics of Waves: Light Waves, Sound Waves and Ultrasound
    What will cause a large percentage of the ultrasound energy to be reflected from the interface between two media? This will happen if:
    A large difference in acoustic impedance will cause a large reflection. Impedance depends on both speed of sound in the medium and the density of the medium.
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    Gastrointestinal System
    When is it considered that food material is outside of the body?
    Food in the gut has not “entered the body” until it has been absorbed into the epithelial lining. This happens after being hydrolysed into molecules that are small enough to be absorbed. The material that is urinated or defecated out is indeed outside the body, but is not considered to be food.
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