00:00 / 00:00
Anatomy and physiology of the female reproductive system
Estrogen and progesterone
Puberty and Tanner staging
Oxytocin and prolactin
Stages of labor
Anatomy and physiology of the male reproductive system
0 / 37 complete
0 / 3 complete
Ovulatory Hormones I - Follicular Phase
Ovulatory Hormones II - Luteal Phase
menstrual cycle p. 652
estrogens for p. 676
The menstrual cycle refers to the regular changes in the activity of the ovaries and the endometrium that make reproduction possible.
The endometrium is the layer of tissue lining the inside of the uterus.
This lining consists of a functional layer, which is subject to hormonal changes and is shed during menstruation, and a thin basal layer which feeds the overlying functional layer.
The menstrual cycle actually consists of two interconnected and synchronized processes: the ovarian cycle, which centers on the development of the ovarian follicles and ovulation, and the uterine or endometrial cycle, which centers on the way in which the functional endometrium thickens and sheds in response to ovarian activity.
Menarche, which refers to the onset of the first menstrual period, usually occurs during early adolescence as part of puberty.
Following menarche, the menstrual cycle recurs on a monthly basis, pausing only during pregnancy, until a person reaches menopause, when her ovarian function declines and she stops having menstrual periods.
The monthly menstrual cycle can vary in duration from 20 to 35 days, with an average of 28 days.
Each menstrual cycle begins on the first day of menstruation, and this is referred to as day one of the cycle.
Ovulation, or the release of the oocyte from the ovary, usually occurs 14 days before the first day of menstruation (i.e., 14 days before the next cycle begins).
So, for an average 28-day menstrual cycle, this means that there are usually 14 days leading up to ovulation (i.e., the preovulatory phase) and 14 days following ovulation (i.e., the postovulatory phase).
Latest on COVID-19
Nurse Practitioner (NP)
Physician Assistant (PA)
Create custom content
Raise the Line Podcast
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
Terms and Conditions
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.