TEST BANK FOR PORTHS PATHOPHYSIOLOGY 10TH EDITION BY NORRIS

Page 1 Chapter 26: Disorders of Blood Flow in the Systemic Circulation 1. If a virus has caused inflammation resulting in endothelial dysfunction, an excessive amount of endothelins in the blood can result in A) arterial wall weakening resulting in aneurysm formation. B) release of excess fatty plaque causing numerous pulmonary emboli. C) contraction of the underlying smooth muscles within the vessels. D) overproduction of growth factors resulting in new vessel production. Ans: C Feedback: Endothelial dysfunction describes several types of potentially reversible changes in endothelial function that occur in response to environmental stimuli. Inducers of endothelial dysfunction include cytokines, bacterial, viral, and parasitic products that cause inflammation. They also influence the reactivity of underlying smooth muscle cells through production of both relaxing factors (nitric oxide) and contracting factors (e.g., endothelins). 2. A nursing instructor is explaining the role of vascular smooth muscle cells in relation to increases in systemic circulation. During discussion, which neurotransmitter is primarily responsible for contraction of the entire muscle cell layer thus resulting in decreased vessel lumen radius? A) Nitric oxide B) Adrenal glands C) Fibroblast growth factor D) Norepinephrine Ans: D Feedback: Nerve cells and circulating hormones are responsible for vasoconstriction of the vessel walls. Because they do not enter the tunica media of the blood vessel, the nerves do not synapse directly on the smooth muscle cells. Instead, they release the neurotransmitter, norepinephrine, which diffuses into the media and acts on the nearby smooth muscle cells, resulting in contraction of the entire muscle cell layer and thus reducing the radius of the vessel lumen. This increases the systemic circulation.