Reproductive Physiology
Chapter Summary:
In this chapter, we learned all about the reproductive system, both male and female.The reproductive system is a very complicated one; especially in the female. It is amazing how many hormones come into play when a baby is growing inside a woman's body. It is also amazing how many things have to be just right in order for the fertilization, implantation and growth of the fetus to happen. Children really are miracles.

As a parent, puberty is pretty much my worst nightmare. Puberty in mammals is triggered by a surge of LH hormone. This increased production of LH hormone is caused by changes in the hypothalamus that allow for secretion of the hormone GnRH. The secretion of the GnRH is what triggers the secretion of the LH. The LH is secreted by the anterior pituitary gland. LH becomes the messenger for the rest of the body that tells it that puberty is going to start. This message triggers the bodily changes that occur during puberty. In girls, puberty begins around age 8 with the appearance of breast buds. Girls will usually have their first menstrual cycle (menarche) between ages 10-16. Every girls is different.
Boys will begin to experience puberty a little later. Boys will begin to notice puberty by the growth of the testicles and appearance of body hair around age 10-11. Their penis will continue to grow during puberty and their voice will become lower. This process takes about 2 years for boys. At that point, they will begin to produce sperm.

For women who are not ready or do not want to have children, various contraceptive methods are often chosen. The most common form being the contraceptive pill, otherwise known as birth control. This type of contraception tricks the body into thinking it is in the early stages of pregnancy and ovulation will not occur. These pills contain high levels of estrogen and progesterone, which are normally produced during pregnancy. The pills are taken for 3 weeks during the menstrual cycle and are providing hormones during that time. The pills are stopped for one week at the end of the cycle and menstruation is allowed to happen. Contraception that is delivered orally must have a higher concentration of hormones because they must pass through the liver prior to being employed within the body. hormone contraception forms that are not delivered through the liver include a subcutaneous implant in the arm (Implanon) and a vaginal ring that is worn for 3 weeks, then removed for one week (Nuva-ring). Because these do not have to pass through the live to be delivered to the intended system in the body, lower doses of hormones can be used.
Fertilization occurs when the sperm cell enters the egg cell. When ovulation occurs, an egg cell is released into the fallopian tube where it is stored until fertilization. When sperm is introduced into the female reproductive system, the sperm cells travel up to the fallopian tubes and if there is an egg waiting for them, it will then be fertilized. The sperm cell carries an covering around it full of enzymes. When the sperm cell encounters the outer layer of the egg cell, the enzyme covering of the sperm cell is released and it breaks down a path for itself through the egg wall. Once it has reached the plasma membrane of the egg cell, the sperm cell and the egg cell become continuous and the nucleus of the sperm cell enters the egg cell. This process is called fertilization.

Application to Nursing:
The concepts of reproductive physiology really hit home for me. My fiancee and I have been trying for a while to have a baby. We were so excited when we found out that we were pregnant but that excitement didn't last long. I had a miscarriage. We aren't sure why, nor will we ever know. One in five pregnancies ends in miscarriage. Often it happens so early that the woman doesn't even know she is pregnant yet. There is a million things that need to be exactly perfect in order for an embryo to grow into a fetus. If just one of these million things is not correct, a miscarriage can happen. A nurse must know not only how to physically care for a patient who is experiencing a miscarriage, but the nurse must know how to emotionally care for them as well. There is sometimes physical pain associated with miscarriage, but more so it is emotional pain. The woman experiencing this will have many questions that the nurse will not be able to answer, but the nurse must be prepared for these questions and how to handle them.

Essential Question:
The menstrual cycle is usually 28 days long. The cycle begins on day 1 of the menstrual bleeding phase. This is called day 1 because it the the most obvious change that occurs. During this phase, the ovaries are in their follicular stage and are waiting for a follicle to mature. During this time, one follicle in one ovary will be come mature enough to be the egg that is involved in ovulation. The follicles stimulate estradiol which will peak about 2 days before ovulation, or the releasing of the egg into the fallopian tube. This process is stimulated by FSH that is released from the anterior pituitary gland. During this time, the proliferative phase is also occurring. During this time, the endometrium of the uterus is developing in preparation to support pregnancy. The increase in estrogen production acts on the hypothalamus and triggers the release of the GnRH hormone. GnRH stimulates the hormone LH which stimulates ovulation. When the egg is eleased into the fallopian tube, it becomes a new structure called a corpus luteum. When this change occurs, the cycle is said to be in the luteal phase. The corpus luteum will then begin the secretory phase and begin to secrete progesterone along with estrogen. It will also inhibit the secretion of FSH and LH. If the egg is fertilized, it will embed itself into the endometrium lining of the uterine wall. If the egg is not fertilized, it will be expelled and the menstruation will begin with the shedding of the uterine lining.