Assistant Laboratory Animal Technician (ALAT) Practice Exam

What is an adverse effect of maintaining temperatures above the TNZ?

1. Decreased water intake

2. Increased aggression

3. Heat stress

4. Reduced appetite

The correct answer is: Heat stress

Maintaining temperatures above the thermoneutral zone (TNZ) can lead to heat stress in laboratory animals. The thermoneutral zone is the range of environmental temperatures where an animal does not need to expend extra energy to maintain its body temperature. When temperatures exceed this range, animals experience physiological stress as they attempt to cool down to a safe body temperature. Heat stress can manifest in several ways, such as increased respiration rates, elevated heart rates, and behavioral changes. In severe cases, it can lead to more serious conditions, including heatstroke or even death. The body's ability to dissipate heat through mechanisms such as sweating or panting may become overwhelmed, resulting in severe dehydration and disruption of metabolic processes. While the other options may have varying degrees of relevance, they do not directly represent the critical consequence of high temperatures specifically associated with exceeding the TNZ. For example, while increased aggression and reduced appetite can occur due to stress or discomfort, they are secondary effects and not a direct physiological response to excessive heat.