When you tutor Biology 12, which is needed for nursing, you cover the male and female reproductive systems.  Here is the continuation from the Dec 30 post.

Previously I discussed the end of the monthly female cycle: if conception does not occur, menstruation does. However, what about the other case: when conception does occur?

The fertilized egg finds lodging in the blood lining of the uterus. Immediately, the placenta starts developing. As it does, it secretes a hormone (HCG) which orders the corpus luteum to continue producing progesterone. The progesterone from the corpus luteum maintains the blood lining in the uterus temporarily. Meanwhile, the placenta develops rapidly; soon, it starts producing its own progesterone. Throughout the pregnancy, the release of progesterone from the placenta will prevent menstruation.

There are a couple of terms that might be helpful. Implantation is the lodging of the fertilized egg in the blood lining of the uterus. The endometrium is the blood lining itself.

For an exploration of the hormonal influences at birthing, stay tuned:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.