Ca-pump and Ion Transport Channels in Cellular Absorption
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Questions and Answers

What is the primary factor influencing absorption through endothelial pores in intramuscular, subcutaneous, and intradermal routes of exposure?

  • Lipid solubility
  • Site of skin thickness
  • Surface area
  • Blood flow (correct)

    • What is the bioavailability of a drug administered intravenously?

  • 50%
  • Ranges from 0 to 100%
  • 100% (correct)
  • 35%

    • Why is it essential to understand bioavailability and extent of absorption for xenobiotics?

  • To determine the optimal dose for therapeutic effects
  • To assess the risk of toxic effects (correct)
  • To identify the most suitable route of administration
  • To evaluate the efficacy of detoxification pathways

    • What is the primary mechanism of destruction of lidocaine in the body?

    <p>Destruction in gastric acid</p> Signup and view all the answers

    What is the term for the phenomenon where a drug is destroyed or metabolized before it reaches the systemic circulation?

    <p>First Pass Effect</p> Signup and view all the answers

    Which route of exposure has a large surface area?

    <p>Intraperitoneal</p> Signup and view all the answers

    What is the primary factor influencing the absorption of xenobiotics through the skin?

    <p>Lipid solubility</p> Signup and view all the answers

    What is the primary factor determining the selective transport of ions through ion channels?

    <p>Size and ionic charge</p> Signup and view all the answers

    Which of the following is an example of a cation transport channel?

    <p>Epithelial calcium channel type 2 (ECaC2)</p> Signup and view all the answers

    What is the primary mechanism of lead absorption from the intestine to the blood?

    <p>Active transport via the epithelial calcium channel type 2 (ECaC2)</p> Signup and view all the answers

    What is the primary effect of lead poisoning on children?

    <p>Neurologic damage and IQ reduction</p> Signup and view all the answers

    What is the primary prevention strategy for chronic lead poisoning?

    <p>Taking calcium supplements and maintaining a diet rich in milk and protein</p> Signup and view all the answers

    What is the radioactive isotope of iodine that can cause thyroid cancer?

    <p>I-131</p> Signup and view all the answers

    What was the event that led to the series of equipment failures and releases of radioactive materials at the Fukushima I Nuclear Power Plant?

    <p>Tōhoku earthquake and tsunami</p> Signup and view all the answers

    What is the primary mechanism by which lead enters the blood from the gut?

    <p>Epithelial calcium transporter</p> Signup and view all the answers

    What is the primary target tissue for blood lead toxicity?

    <p>Brain</p> Signup and view all the answers

    Which of the following xenobiotics is NOT sequestered in adipose tissue?

    <p>Aflatoxin</p> Signup and view all the answers

    What is the purpose of depot sequestration and mobilization in the context of xenobiotic toxicity?

    <p>To reduce the toxicity of xenobiotics by sequestering them in depot stores</p> Signup and view all the answers

    Which of the following xenobiotics is characterized by a short-acting effect due to re-distribution from the brain to fat?

    <p>Thiopental</p> Signup and view all the answers

    What is the primary consequence of depot mobilization of sequestered xenobiotics during pregnancy and breast feeding?

    <p>Redistribution of xenobiotics to the fetus or breast milk</p> Signup and view all the answers

    What is the primary mechanism of elimination for xenobiotics such as ammonia and volatile organic compounds?

    <p>Exhalation through the lungs</p> Signup and view all the answers

    What is the primary reason for the low bioavailability of certain xenobiotics in extracellular fluid?

    <p>Binding to albumin reduces their availability</p> Signup and view all the answers

    Which of the following statements about brain capillaries is true?

    <p>Their cell membrane is sealed shut, preventing the passage of toxic substances</p> Signup and view all the answers

    What is the effect of tolbutamide binding to plasma albumin?

    <p>It increases the bioavailability of tolbutamide</p> Signup and view all the answers

    What is the purpose of the blood-brain barrier (BBB)?

    <p>To protect the brain from toxic substances in the blood</p> Signup and view all the answers

    What is the effect of competition-displacement between xenobiotics on their bioavailability?

    <p>It increases the bioavailability of one xenobiotic and decreases the bioavailability of the other</p> Signup and view all the answers

    What is the purpose of sequestration in animals?

    <p>To store toxicants in inert tissues, reducing their toxic effects</p> Signup and view all the answers

    What is the difference between normal blood capillaries and brain capillaries?

    <p>Normal blood capillaries are fenestrated, while brain capillaries are unfenestrated</p> Signup and view all the answers

    What is the primary mechanism of excretion for water-soluble toxicants with a molecular weight of less than 70,000?

    <p>Passive transport through the kidney</p> Signup and view all the answers

    Which of the following elimination routes involves both filtration and reabsorption processes?

    <p>Kidney</p> Signup and view all the answers

    What is the primary function of the liver in the elimination of toxicants?

    <p>Metabolism of lipid-soluble toxicants to more water-soluble molecules</p> Signup and view all the answers

    What is the significance of mother's milk as an elimination route?

    <p>It is an important route of transfer of toxicants to babies and from animals to humans</p> Signup and view all the answers

    What is the mechanism of excretion of conjugates with high molecular weight?

    <p>Active transport into bile</p> Signup and view all the answers

    What is the fate of lipid-soluble and non-ionized toxicants in the body?

    <p>They are reabsorbed into the bloodstream, leading to systematic toxicity</p> Signup and view all the answers

    What is the primary route of elimination for gases and volatile liquids?

    <p>Lung</p> Signup and view all the answers

    What is the role of the GIT in the elimination of toxicants?

    <p>It is involved in the excretion of toxicants through simple diffusion</p> Signup and view all the answers

    What is the significance of sweat and saliva as elimination routes?

    <p>They are minor routes of elimination for lipid-soluble toxicants</p> Signup and view all the answers

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