Anatomy and Physiology

    Endocrine System
    Which of the following statements about corticosteroids is true?
    They are produced by the adrenal cortex.
    Author: rikazzz Comment
    Cardiovascular System
    Which of the following descriptions refers to the “pulmonary circulation”?
    The pulmonary circulation is the circuit from the heart through the lungs and back again. It occurs because of the pumping action of the right ventricle sending blood through the pulmonary artery.
    Author: rikazzz Comment
    Cardiovascular System
    Why does the heart rate increases during exercise? To:
    Heart rate and hence cardiac output must rise to increase blood pressure. A higher BP increases the rate of blood flow, so blood can supply the active muscles with more oxygen and glucose, so these materials can be used to produce ATP which supply energy for the exercise.
    Author: rikazzz Comment
    Respiratory System
    What does it mean when the concentration of dissolved oxygen in blood is 100 mmHg?
    The concentration of a gas dissolved in water is expressed in terms of the partial pressure of that gas in the mixture of gases that were in contact with the water. Gas will continue to dissolve until the water is saturated. At this point we say that the concentration of dissolved gas is the same as the partial pressure of that gas in the atmosphere in contact with the water. The same units, mmHg are used.
    Author: rikazzz Comment
    Nervous System
    Which neurotransmitter do all motor neurons release at their synapses with skeletal muscle cells?
    Motor neurons release acetylcholine.
    Author: rikazzz Comment
    Respiratory System
    If the partial pressure of oxygen in alveolar air is 100 mmHg and the concentration of dissolved oxygen in capillary blood arriving at the alveoli is 40 mmHg, what will be the concentration of dissolved oxygen in blood leaving the alveoli?
    Oxygen in alveolar air will diffuse down its concentration gradient into capillary blood until blood in the capillary is also at 100 mmHg. After this there is no concentration gradient to effect a net diffusion.
    Author: rikazzz Comment
    Cardiovascular System
    Blood may flow in the aorta with a speed of 30 cm/s and in the capillaries with a speed of only 0.1 m/s. Why is there such a large difference in speed?
    The “equation of continuity” may be stated: volume flow rate = cross- sectional area × speed of flow. Hence if the total cross-sectional area of capillaries is very large (as it is), the speed of flow can be very slow while still allowing the required volume flow rate.
    Author: rikazzz Comment
    Body Temperature, Energy and Heat Loss
    Which of the statements about heat is true? Heat is:
    Heat is the energy that is transferred between two objects due to their difference in temperature. Infrared radiation is one form of heat (but not the reverse).
    Author: rikazzz Comment
    Measurement, Errors, Data and Unit Conversion
    Which of the following g does NOT describe a milligram?
    This (1 × 103 g) is 1000 = 1 kg.
    Author: rikazzz Comment
    Ionising Radiation
    What does the “relative biological effectiveness” (RBE) of radiation depend on?
    If radiation deposits energy of 1 MeV along its path of 1 mm, more damage would be produced (the radiation would be more “effective”) than if the 1 MeV of energy deposited was spread out along a path length of 10 cm.
    Author: rikazzz Comment