The Monitoring Studies On The Sheep Fetus During The Mid To Late Pregnancy Period

The changes in amniotic fluid of absorbance, total bilirubin, creatinine and phospholipids contents were studied by using spectrophotometer, detecting kit, and one-dimensional thin-layer chromatography; the outer shape and inner organs' weight were measured by scales; the structure changes of several inner organs were studied by light microscope and transmission electron microscope. The objectives of the study were to discover the changes of the outer shape and the inner organs' weight, the changes rules of the microstructure and ultrastructure in these organs, and the relationship between amniotic fluid index and fetal maturity during the mid to late pregnancy period. The results showed that:1. the amniotic absorbance and phospholipids level studies and ultrastructure observation results showed that the amniotic fluid index can be used to indicate fetal maturity. The standards for fetal maturity were: (1) absorbance at 650nm >0.20; (2) the lecithin and sphingomyelin ratio(L/S )>2;(3) the phosphatidylglycerol (PG) positive in amniotic fluid.2 The hair of the sheep fetus were first observed in 100 days of the gestation by naked eyes only at the place of horn swelling, lower mandible and neck, by 120 days of gestation the fetus body was all covered by hair. In addition, the skin of the fetal sheep was growing faster at 120 days of gestation.3 The light microscope observation results showed that the structure of the fetal heart was well developed by 80 days of gestation; the fetal liver was a hematopoietic organ. It's function reached the highest at 100 days of gestation, then declined The hematopoietic function of the fetal liver disappeared when the fetus was delivered. The structure of the fetal liver was well developed by 100 days of gestation, but it's function matured at 140 days of gestation; the kidneys already had the urine filtering function at 80 days of gestation. Their structure and function were well developed by 120 days of gestation. There were several kind of renal corpuscles in different periods coexisted in the cortex of the fetal kidneys, which was the development pattern of the renal corpuscles in fetal kidneys. The renal corpuscle in deeper cortex matured first There were new renal corpuscles forming constantly in the shallow cortex, which made the cortex thicken; the fetal spleen was a hematopoietic organ. It's hematopoietic function was declined at 120 days of gestation, but still existed after birth. In addition, the period from 100 days to 120 days of gestation was an important time for the fetal spleen to change from a hematopoietic organ to immune organ.4 The results from light microscope and transmission electron microscope observation of the fetal lungs showed that the structure of the fetal lungs were well developed by 140 days ofgestation. The type II cells in alveolus began to differentiate at 100 days of gestation and appeared in maturity shape at 120 days of gestation; The thickening of the fetal sheep adrenal cortex was the result of increasing of the zona fasciculata. The synthetic activities of the cells in zona fasciculata increased with the fetal development, and the synthetic function was strong at delivery.5 The transmission electron microscope observation results of fetal anterior pituitary showed that the synthetic and secretion activities increased with the fetal developmentGraduate students: Xiujun Fan Speciality: Clinical Veterinary Medicine Supervisor: Professor Wenru Tian...