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The blood flow through the umbilical cord is approximately 35 mL/min at 20 weeks, and 240 mL/min at 40 weeks of gestation. [18] Adapted to the weight of the fetus, this corresponds to 115 mL/min/kg at 20 weeks and 64 mL/min/kg at 40 weeks. [ 18 ]
An oocyte (/ ˈ oʊ ə s aɪ t /, oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction.In other words, it is an immature ovum, or egg cell.An oocyte is produced in a female fetus in the ovary during female gametogenesis.
Studies performed on humans, dogs, and cats in the 1870s suggested that the production of oocytes (immature egg cells) stops at or shortly after birth. A review of reports from 1900 to 1950 by zoologist Solomon Zuckerman cemented the belief that females have a finite number of oocytes that are formed before they are born. This dogma has been ...
The volume of amniotic fluid changes with the growth of fetus. From the tenth to the 20th week it increases from 25 to 400 millilitres (0.88 to 14.08 imp fl oz; 0.85 to 13.53 US fl oz) approximately. [3] Approximately in the 10th–11th week, the breathing and swallowing of the fetus slightly decrease the amount of fluid.
Under ultrasound guidance, the operator inserts a 16.5 gauge × 11.8″ (1.6 mm × 300 mm outer diameter) needle through the vaginal wall and into an ovarian follicle, taking care not to injure nearby organs and blood vessels. The other end of the needle is attached to a suction device.
The sperm binds through the corona radiata, a layer of follicle cells on the outside of the secondary oocyte. The corona radiata sends out chemicals that attract the sperm in the fallopian tube to the oocyte. It lies above the zona pellucida, a membrane of glycoproteins that surrounds the oocyte. [14]
Pressure drops gradually as blood flows from the major arteries, through the arterioles, the capillaries until blood is pushed up back into the heart via the venules, the veins through the vena cava with the help of the muscles. At any given pressure drop, the flow rate is determined by the resistance to the blood flow.
An intricate network of capillary vessels forms between these two thecal layers and begins to circulate blood to and from the follicle. The late-term secondary follicle is marked histologically and structurally by a fully grown oocyte surrounded by a zona pellucida, approximately nine layers of granulosa cells, a basal lamina, a theca interna ...