ALAT ALAT Species-Specific Care and Experimental Models Questions and Answers 4

Question 1

Which of the following best describes the normal estrous cycle length in female rats?

Accepted Answer

4-5 days

Answer

Female rats have a short estrous cycle of approximately 4-5 days, cycling through proestrus, estrus, metestrus, and diestrus.

Question 2

A rabbit is observed pressing its abdomen against the cage floor and grinding its teeth. These signs most likely indicate:

Accepted Answer

GI pain or discomfort

Answer

Teeth grinding (bruxism) and hunched posture with abdominal pressing are classic signs of gastrointestinal pain in rabbits.

Question 3

Which species is considered an obligate nasal breather and is particularly susceptible to upper respiratory infections that can quickly become life-threatening?

Accepted Answer

Guinea pig

Answer

Guinea pigs are obligate nasal breathers, making upper respiratory infections especially dangerous as they cannot compensate by breathing through their mouths.

Question 4

In a xenograft tumor model, which type of mouse is most commonly used as the host?

Accepted Answer

Athymic nude mice or SCID mice

Answer

Xenograft models require immunodeficient hosts such as athymic nude or SCID mice so that human tumor cells are not rejected.

Question 5

What is the primary reason gerbils are used in cerebral ischemia research?

Accepted Answer

They lack a complete Circle of Willis, making unilateral carotid ligation effective

Answer

Gerbils naturally lack posterior communicating arteries completing the Circle of Willis, so ligating one carotid artery reliably produces unilateral brain ischemia.

ALAT - Assistant Laboratory Animal Technician Practice Test

ALAT - Assistant Laboratory Animal Technician Practice Test

ALAT ALAT Species-Specific Care and Experimental Models Questions and Answers 4