A scientist observes a particular nerve fiber that is among the fastest at conducting action potentials in the body. Which of the following best describes its likely structure?
A. Large diameter and myelinated
B. Large diameter and unmyelinated
C. Small diameter and myelinated
D. Small diameter and unmyelinated
A
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Which of the following leukocytes become macrophages and phagocytize dead and dying tissue, microorganisms, and any other foreign matter or debris?
A. Lymphocytes B. Eosinophils C. Monocytes D. Basophils
Prions are infectious proteins within cells that cause normal proteins to misfold and clump together. Prions can occur as a result of a mutation or ingestion, e.g., Mad Cow disease (eating infectious beef from an animal with the disease). Creutzfeldt-Jakob disease and scrapie are prion diseases in both animals and humans. The diseases are progressive, have no cure, and end in death. Using your chemistry knowledge, explain the devastating effects of these diseases.
What will be an ideal response?
Homeostatic regulatory mechanisms known as ________ are "built-in" to the organs being regulated.
A. passive B. intrinsic C. extrinsic D. exothermic
Which of the following is involved in the regulation of thyroid hormone levels?
A. thyroglobulin in thyroid follicles B. thyroid-stimulating hormone from the anterior pituitary C. positive feedback mechanisms D. parathyroid hormone levels E. blood calcium levels