Anatomy and Physiology

    Nervous System
    What is meant by an absolute refractory period?
    During the ~0.5 ms period of the action potential in which sodium ions are rushing into a nerve cell, the nerve cannot respond to any stimulus no matter how strong the stimulus is. Because of the impossibility of response, this period is called “absolutely” refractive (refractory = resisting ordinary methods).
    Author: rikazzz Comment
    Muscles
    What causes the myosin binding site of an actin molecule to be exposed?
    Ca causes a change of shape to the troponin molecule when they attach. This causes troponin to wrench tropomyosin away from its resting position covering the binding site.
    Author: rikazzz Comment
    Reproductive System
    What is the name given to a young woman’s first menstrual period?
    Menarche is the first menstrual cycle, or first menstrual bleeding, in female humans.
    Author: rikazzz Comment
    Reproductive System
    After ejaculation, sperm travel through the structures of the female reproductive tract in which order?
    Sperm eventually reach the fallopian tube after gaining entry to the uterus via the cervix. The urethra is not part of the female reproductive tract.
    Author: rikazzz Comment
    Cardiovascular System
    What substance is the product of the second step in the blood clotting process?
    The second step is the formation of thrombin from prothrombin (first step is formation of prothrombinase (=prothrombin activator)).
    Author: rikazzz Comment
    Respiratory System
    When a peak flow meter is used to measure maximum expiratory flow rate, why is the measurement repeated many times?
    Maximum speed of expired air flow measures the airflow through the bronchi and thus the degree of obstruction in the airways. Peak flow readings are higher when patients are well and lower when the airways are constricted. The highest value contains the required information, while values taken with less than maximum effort do not provide any reliable information.
    Author: rikazzz Comment
    Muscles
    The muscle known as the “transversus abdominis” is named according to:
    Its location = abdominis; its muscle fibre direction = transversus.
    Author: rikazzz Comment
    Cardiovascular System
    What two-layered membranous sac surrounds the heart?
    “Peri-” refers to surrounding, while “-cardium” refers to the heart.
    Author: rikazzz Comment
    Chemistry for Physiology
    What chemical symbol for the element/atom occurs in an amino acid but not in fats and carbohydrates?
    Amino acids contain an “amine” group – a nitrogen atom bonded to a hydrogen atom. Nitrogen atoms do not occur in fats or carbohydrates.
    Author: rikazzz Comment
    Chemistry for Physiology
    A buffered solution is able to resist change to its pH when an acid is added to the solution by doing which of the following?
    A buffered solution contains two entities, one of which can remove hydronium ions from solution, turning them into water. Sometimes “hydrogen ions” is used instead of the more correct hydronium ions. Hydrogen peroxide is not produced by adding acid to a solution.
    Author: rikazzz Comment