https://sciencewithsusanna.com has diagrams, notes, and practice questions. Quizlet - https://quizlet.com/_6qhax2 The uterus is a muscular organ designed to stretch to accommodate a growing fetus, and to be strong enough to push out a baby during labor and delivery. The myometrium is the muscular wall. The endometrium is the inner lining that nourishes a developing baby. The cervix is the opening to the uterus. The fallopian tubes connect the ovaries to the uterus. The ovaries mature eggs under the influence of estrogen. Estrogen is regulated by FSH and LH from the pituitary gland. LH causes ovulation, after which the corpus luteum (yellow body) remains behind in the ovary and produces progesterone. The first two weeks of the ovarian cycle are referred to the as the follicular phase - estrogen dominates and causes egg maturation. After ovulation, progesterone (released from the corpus luteum) dominates and thickens the uterine lining - this is referred to as the luteal phase. Ovarian cysts are fluid-filled, sometimes painful sacs that develop on ovaries. They are common in polycystic ovarian syndrome and from some types of birth control. They are generally an indication of abnormal hormonal levels or cycles. The fallopian tubes are ciliated and move the egg along. Fertilization, if it occurs, happens in the fallopian tubes. Implantation occurs in the uterus in the endometrium. The vagina is a muscular tube that contracts during orgasm, allowing the cervix to dip down into any deposited semen and increase sperm transfer efficiency. Fraternal twins occur when more than one egg is ovulated. Identical twins occur when one fertilized egg splits into two very early in embryonic development. Ectopic pregnancies may occur if the fallopian tubes have been scarred from infection and the egg implants too early. Endometriosis is when endometrial tissue forms outside of the uterus.