Secretions that affect only nearby cells are termed:
Autocrine.
Endocrine.
Exocrine.
Paracrine.
The Correct Answer is D
Paracrine secretions are chemical signals that affect only nearby cells.
They are released by the sending cell and diffuse through the extracellular space to the target cell, which has a specific receptor for the signal.
Paracrine signaling is a form of local signaling that occurs in multicellular organisms.
Choice A is wrong because autocrine secretions are chemical signals that act on the same cell that produced them.
Autocrine signaling is also a form of local signaling, but it involves cell signaling itself.
Choice B is wrong because endocrine secretions are chemical signals that are secreted into the blood and act at long distances.
Endocrine signaling is a form of long-range signaling that involves ductless glands that secrete hormones.
Choice C is wrong because exocrine secretions are non-hormonal substances that are secreted into ducts to the external environment.
Exocrine signaling is not a form of cell-cell communication, but rather a way of releasing substances such as sweat, saliva, or digestive enzymes.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Pathogens are disease-causing agents. They can be bacteria, viruses, fungi, protists, or parasitic worms.
They can infect other organisms and cause various diseases.
Choice A is wrong because phagocytic leukocytes are a type of white blood cell that can engulf and destroy pathogens.
They are part of the immune system and help fight infections.
Choice B is wrong because antibodies are proteins that can bind to specific antigens on the surface of pathogens and mark them for destruction by other immune cells.
They are also part of the immune system and help fight infections.
Choice D is wrong because agents that alter DNA base sequences are not necessarily pathogens.
They can be mutagens, such as chemicals or radiation, that can cause changes in the DNA of cells.
Some mutagens can also be carcinogens, which can cause cancer.
Correct Answer is B
Explanation
As a result of the allergen-antibody reaction, mast cells release histamine.
This is because when mast cells are exposed to an allergen that binds to IgE antibodies attached to their FcɛRI receptors, they release histamine and other inflammatory mediators.
Histamine causes vasodilation, increased capillary permeability, mucus secretion, and smooth muscle contraction, which result in allergic symptoms such as itching, swelling, sneezing, and wheezing.
Mast cells do release histamine in response to allergen-antibody reactions. Some additional sentences are:
Normal ranges of histamine levels vary depending on the tissue and the method of measurement, but they are usually low in healthy individuals and elevated in allergic conditions.
Histamine can be degraded by enzymes such as diamine oxidase and histamine N- methyltransferase, or inhibited by drugs such as antihistamines.
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