The stomach has three types of contractions: There are rhythmic, 3 per minute, synchronized contractions in the lower part of the stomach, which create waves of food particles and juice which splash against a closed sphincter muscle (the pyloric sphincter) to grind the food into small particles.
7 What is the gestation period, how many babies do they have, and when are they weaned? 1  The gestation period for rats is 19â22 days, for mice it is 17â21 days.  Rats and mice average 8â12 babies in a litter, but can have as few as 1 or as many as 20.
However, when female rats were given oral doses of lapatinib during breeding and through the first 6 days. of gestation, a significant decrease in the number of live fetuses was seen at 120 mg/kg/day and. in the fetal body weights at â¥60 mg/kg/day (approximately 6.4 times and 3.3 times the expected.