Search results
Results From The WOW.Com Content Network
In addition to sideward bendings of the head, complex and generalized movements occur at the beginning of the fetal stage, with movements and startles that involve the whole body. [11] Movement of hands, hips and knees have been observed at nine weeks, [12] stretches and yawns at ten weeks, [13] and isolated limb movements beginning shortly ...
Quickening indicates the start of fetal movements, usually felt 14–26 weeks after conception, or between the fourth and sixth month. [ 5 ] [ 6 ] A woman pregnant for the first time (i.e., a primigravida woman) typically feels fetal movements at about 20–21 weeks, whereas a woman who has given birth at least once will typically feel ...
During pregnancy the plasma volume increases by 40-50% and the red blood cell volume increases only by 20–30%. [22] These changes occur mostly in the second trimester and prior to 32 weeks gestation. [24] Due to dilution, the net result is a decrease in hematocrit or hemoglobin, which are measures of red blood cell concentration.
A sperm cell fertilizing an egg cell. Fertilization marks the first germinal stage of embryonic development.When semen is released into the vagina, the spermatozoa travel through the cervix, along the body of the uterus, and into one of the fallopian tubes where fertilization usually takes place in the ampulla.
The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth.
For premium support please call: 800-290-4726 more ways to reach us
The inner cell mass will give rise to the pre-embryo, [9] the amnion, yolk sac and allantois, while the fetal part of the placenta will form from the outer trophoblast layer. The embryo plus its membranes is called the conceptus, and by this stage the conceptus has reached the uterus.
However, carrying fetuses exerts costs on the mother, who must take on extra food to fuel the growth of her offspring, and whose mobility and comfort may be affected (especially toward the end of the fetal stage). In some instances, the presence of a fetal stage may allow organisms to time the birth of their offspring to a favorable season. [40]