Anatomy and Physiology

    Chemistry for Physiology
    Osmosis involves the movement of:
    Osmosis involves water molecules (not solutes) moving down their concentration gradient into a solution of lower concentration of water molecules.
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    Chemistry for Physiology
    Which of the following is a polysaccharide?
    Choice A is an enzyme (“-ase”), B is a hormone and C is a monosaccharide.
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    Cells and Tissues
    Which of the following is a function of membrane proteins?
    One function of membrane proteins is to receive (amino acid-based) hormones that cannot pass through the plasma membrane.
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    Nervous System
    In the peripheral nervous system, which cells form the myelin sheath?
    Schwann cells surround the axon to form the myelin sheath in peripheral neurones. Oligodendrocytes perform a similar function for neurones in the CNS.
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    Respiratory System
    What does it mean if oxygenated blood leaving the alveolar capillaries has an oxygen partial pressure of 100 mmHg?
    A pp. of 100 mmHg is a way of expressing the concentration of oxygen that is dissolved in blood. Oxygen will continue to move into blood from the alveoli as long as the oxygen concentration in blood is less than that in the alveoli. If ppO2 in the alveoli is 100 mmHg, then the ppO2 in the blood will continue to increase until it is equal to that in the alveoli.
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    Nervous System
    Which of the following is true of parasympathetic neurons?
    All parasympathetic neurons release ACh as a neurotransmitter. Choices A and D are true of the sympathetic division.
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    Cardiovascular System
    Which tunic(s) are ABSENT from the walls of blood capillaries?
    Capillaries are thin-walled vessels that only have the tunica intima (= interna) in their walls. Hence the tunica media and tunica externa are absent.
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    Respiratory System
    Patients with diabetes mellitus who neglect insulin therapy rapidly metabolise lipids, and there may be an accumulation of the acidic by-products of lipid metabolism in the blood. What effect would this have on respiration?
    Respiratory rate increases if blood pH decreases in order to breathe out carbon dioxide (and hence reduce acid). In uncontrolled diabetics, this is known as Kussmaul breathing.
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    Skeleton and Joints
    The tibia articulates distally with which one of the following?
    Distal refers to the end that is further away from the trunk. Hence the ankle bone (tarsals) is the correct choice.
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    Renal System
    If the blood’s concentration is rising towards 300 mosmol/L, more ADH would be released. What effect would this have on the concentration of blood?
    Blood concentration rises as water is lost from the body by evaporation, and urine is formed. ADH causes water to be reabsorbed from the kidney filtrate, so the rise in blood concentration would slow as more water is returned to the blood rather than being filtered out into urine. Blood concentration would not fall until some water has been drunk.
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