TEST BANK for Advanced Physiology & Pathophysiology;Essentials for Clinical Practice 2nd Ed by Tkacs

Chapter 1. The foundational Concepts of Clinical Practice MULTIPLE CHOICE 1. The type of control system that can sometimes cause instability and vicious cycles is called A) negative feedback. B) feed-forward control. C) positive feedback. D) adaptive feedback. E) delayed negative feedback. ANS: C Feedback: Positive feedback amplifies a change in the system, often leading to instability or vicious cycles. For example, in certain pathological conditions, positive feedback can exacerbate the problem rather than stabilizing it, unlike negative feedback systems, which promote homeostasis. 2. Which of the following is an example of positive feedback in the body? A) Return of blood pressure toward normal after a hemorrhage B) Generation of action potentials in nerves C) Increased respiration rate caused by accumulation of carbon dioxide in the blood D) Decreased sympathetic nervous system activity that occurs in response to increased blood pressure ANS: B Feedback: Positive feedback in nerve action potentials occurs when the depolarization of the membrane causes sodium channels to open, leading to further depolarization. Other options, such as the return of blood pressure to normal after hemorrhage, are examples of negative feedback. 3. The vascular, hemodynamic stage of acute inflammation is initiated by momentary vasoconstriction followed by vasodilation that causes localized: A) bleeding. B) congestion. C) pale skin. D) coolness. ANS: B Feedback: Vasodilation increases blood flow to the injured area, causing localized congestion, which is the accumulation of blood in the vessels. This leads to redness and warmth. Bleeding and coolness are not typical of the hemodynamic stage, and pale skin would result from vasoconstriction, not vasodilation.