In addition to chemistry, physics, and biochemistry, the MCAT is interested in testing your knowledge of biology as well. One particularly important topic emphasized in the “Biological and Biochemical Foundations of Living Systems” section is reproductive health. This article will provide you with a short outline of information regarding the reproductive system that is essential in preparation for your upcoming MCAT.
One particularly significant topic in reproductive health is understanding the role of both gonads and genitalia. Male gonads, also known as testes, are responsible for the production of sperm and testosterone. In contrast, female gonads are responsible for holding immature oocytes and producing estrogen. In addition to understanding the function of gonads, it is crucial to develop a greater understanding of hormones. The hypothalamus and anterior and posterior pituitaries are responsible for the secretion of key hormones associated with human reproduction. The hypothalamus secretes GnRH, gonadotropin-releasing hormone, which then signals the anterior pituitary to produce LH, luteinizing hormone, and FSH, or follicle-stimulating hormone. These two hormones are then secreted to the previously-mentioned gonads for secretion of either estrogen in biological females or testosterone in biological males. This information regarding the hypothalamic-pituitary-ovarian, or HPO, axis is closely related to the endocrine system, which plays a significant role in all three science sections of the MCAT.
Another important aspect of menstrual health that is commonly covered in the MCAT is the menstrual cycle. It is crucial to understand each phase, along with hormonal and endometrial changes throughout each phase of the cycle. During menses, a portion of the follicular phase, the uterine lining, also known as the endometrium, is sloughed off. Following menses, the next portion of the follicular phase occurs, involving a follicle growing in preparation for ovulation. During this proliferative phase, the hormone estrogen increases in concentration significantly, indicative of the type of surge. It should also be noted that it is typically this proliferative stage that allows for variation in the duration of one’s menstrual cycle. All other stages of the menstrual cycle typically last the same amount of time.
Following this proliferative phase is the stage of ovulation. Ovulation is the process by which a fully matured oocyte is released from the ovary. Ovulation is usually accompanied by a surge in LH and FSH. After ovulation, the start of the luteal phase occurs. During this phase, the corpus luteum develops. In the case that the oocyte becomes fertilized, the corpus luteum will work to produce substantial amounts of progesterone. However, if the oocyte is not fertilized, this developed corpus luteum ultimately regresses, resulting in the sloughing off of the endometrium observed in menses.
Overall, I hope the information provided in this article will assist you with better approaching questions regarding reproductive health on the MCAT. Happy studying!
Thank you so much for reading!