Anatomy and Physiology

    Ionising Radiation
    The intensity of gamma radiation decreases as the inverse square of the distance. What does this statement mean? If the distance doubles, then the intensity:
    If the distance doubles, the inverse is ½. The square of the inverse is (½)2 = 1/4.
    Author: rikazzz Comment
    Gastrointestinal System
    Which of the following organs is an accessory organ of the gastrointestinal tract?
    The other three are all part of the digestive tract itself.
    Author: rikazzz Comment
    Respiratory System
    To what does “internal respiration” refer?
    Internal respiration refers to the movement of oxygen from the blood into the interstitial fluid and CO2 from interstitial fluid to blood. It also refers to the diffusion of these gases through the interstitial fluid to and from the cells.
    Author: rikazzz Comment
    Cells and Tissues
    Which of the following is NOT classed as a lipid?
    Examples of lipids are waxes, fats, oils, steroids, cholesterol and phospholipids. Keratin is a protein (the “-in” ending to keratin denotes that).
    Author: rikazzz Comment
    Respiratory System
    Why is it that bronchioles can constrict and so reduce their diameter while secondary bronchi and respiratory bronchioles cannot constrict?
    Because bronchioles have no cartilage in their walls, they are able to dilate and constrict to alter the amount of air that enters the alveoli. Respiratory bronchioles that feed into alveolar ducts have little smooth muscle and no cartilage.
    Author: rikazzz Comment
    Nervous System
    What part of the brain receives sensory input before passing it on to another part of the brain for interpretation or action?
    The thalamus relays visual and auditory information.
    Author: rikazzz Comment
    Measurement, Errors, Data and Unit Conversion
    What is the number 0.028 when correctly expressed in scientific notation?
    Scientific notation requires one number to the right of the decimal point (choices B and C). The decimal point must be shifted two places to achieve this. As 0.028 is less than one, the power of 10 is negative.
    Author: rikazzz Comment
    Cardiovascular System
    Why does the lumen of a large vein have a larger diameter than the lumen of a large artery?
    Veins contain about 60% of the blood volume (and because they have thinner walls, they are also more distensible than arteries).
    Author: rikazzz Comment
    Nervous System
    What is the purpose of a neurotransmitter?
    Choices C and D are also correct, but B is the more general answer.
    Author: rikazzz Comment
    Cardiovascular System
    What is a small artery called?
    A small artery or arteriole may be 30 μm (0.03 mm) in diameter.
    Author: rikazzz Comment