**Question:** Sympathetic stimulation causes all of the following except

A. Increased heart rate
B. Decreased cough reflex
C. Increased bronchoconstriction
D. Decreased sweating

**Correct Answer:** D. Decreased sweating

**Core Concept:**
Sympathetic stimulation is part of the body's "fight or flight" response and is mediated by the sympathetic division of the autonomic nervous system. This response typically leads to a range of physiological changes aimed at preparing the body for increased activity or stress. The correct answer, decreased sweating, is an example of a counterregulatory response to counteract the effects of the sympathetic response.

**Why the Correct Answer is Right:**
Sweating is a crucial physiological mechanism for maintaining body temperature homeostasis by evaporating sweat from the skin surface. When sympathetic stimulation occurs, it inhibits the sweat glands, which results in decreased sweating. This helps to conserve water and reduce heat loss during periods of physical or psychological stress.

**Why Each Wrong Option is Incorrect:**

A. Increased heart rate: Sympathetic stimulation increases cardiac output to meet increased oxygen demands during stress or physical activity. This is generally considered a beneficial response.

B. Decreased cough reflex: This option is incorrect because a decrease in the cough reflex would not be a desirable outcome during upper respiratory tract infections or inhalation of irritants. A well-functioning cough reflex is essential for removing foreign particles and pathogens from the respiratory tract.

C. Increased bronchoconstriction: Sympathetic stimulation can cause bronchoconstriction, which narrows the airways and reduces lung function. This is considered a detrimental response in asthma patients or individuals with respiratory issues.

**Clinical Pearl:**
Understanding the physiological effects of sympathetic stimulation is crucial for healthcare professionals to effectively manage patients in various clinical settings. For example, in certain cases, like asthma exacerbation or hypotension, an increased sympathetic response may be required to counteract the detrimental effects of decreased sweating, bronchoconstriction, and decreased cough reflex. However, in other situations, such as respiratory infections, sympathetic stimulation might exacerbate the condition by causing bronchoconstriction.