Assistant Laboratory Animal Technician (ALAT) Practice Exam

Which anatomical characteristic distinguishes rats from mice?

1. Pinna size

2. Presence of a gallbladder

3. Body length

4. Lack of gallbladder

The correct answer is: Lack of gallbladder

The anatomical characteristic that distinguishes rats from mice is the lack of a gallbladder in rats. This is a significant difference in the digestive anatomy of these two rodent species. The absence of a gallbladder in rats means that bile is continuously secreted from the liver directly into the intestine, rather than being stored and concentrated as in species that have a gallbladder. This anatomical feature can influence various aspects of digestion and metabolism in these animals. Understanding this difference is crucial for laboratory animal technicians, as it may affect dietary considerations, pharmacokinetics of drugs, and the overall health management of these animals. This knowledge helps ensure that care and experimental protocols are appropriately tailored to the specific needs of rats compared to mice.