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The follicular phase (or proliferative phase) is the phase of the estrous cycle, (or, in humans and great apes, the menstrual cycle) during which follicles in the ovary mature. It ends with ovulation. The main hormone controlling this stage is estradiol.[1] Image File history File links Size of this preview: 424 × 600 pixelsFull resolution (794 × 1123 pixel, file size: 92 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Menstruation Menstrual cycle ...
Image File history File links Size of this preview: 424 × 600 pixelsFull resolution (794 × 1123 pixel, file size: 92 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Menstruation Menstrual cycle ...
The estrous cycle (also oestrous cycle; originally derived from Latin oestrus) comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. ...
Genera Subfamily Ponginae Pongo - Orangutans Gigantopithecus (extinct) Sivapithecus (extinct) Subfamily Homininae Gorilla - Gorillas Pan - Chimpanzees Homo - Humans Paranthropus (extinct) Australopithecus (extinct) Sahelanthropus (extinct) Ardipithecus (extinct) Kenyanthropus (extinct) Pierolapithecus (extinct) (tentative) The Hominids (Hominidae) are a biological family which includes humans, extinct species of humanlike creatures and the other great apes...
Menstrual cycle The menstrual cycle is a recurring cycle of physiologic changes that occurs in the females of several mammals, including human beings and other apes. ...
// For ovary as part of plants see ovary (plants) An ovary is an egg-producing reproductive organ found in female organisms. ...
Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ...
Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ...
Hormonal events
Follicle recruitment Follicle-stimulating hormone (FSH) is secreted by the anterior pituitary gland. FSH secretion begins to rise in the last few days of the previous menstrual cycle,[2] and is highest and most important during the first week of the follicular phase.[3] The rise in FSH levels recruits five to seven tertiary-stage ovarian follicles (this stage follicle is also known as a Graffian follicle or antral follicle) for entry into the menstrual cycle. These follicles, that have been growing for the better part of a year in a process known as folliculogenesis, compete with each other for dominance. Follicle stimulating hormone Follicle stimulating hormone (FSH) is a hormone synthesised and secreted by gonadotropes in the anterior pituitary gland. ...
The anterior pituitary (also called the adenohypophysis, from Greek adeno, gland; hypo, under; physis, growth; hence, glandular undergrowth) comprises the anterior lobe of the pituitary gland and is part of the endocrine system. ...
Human submaxillary gland. ...
Ovarian follicles or Graafian follicles (after Regnier de Graaf) are the roughly spherical cell aggregations in the ovary containing an ovum and from which the egg is released during ovulation. ...
The follicular antrum is the portion of an ovarian follicle filled with liquor folliculi. ...
In biology, folliculogenesis refers to the maturation of the ovarian follicle, a densely-packed shell of somatic cells that contains an immature oocyte. ...
FSH induces the proliferation of granulosa cells in the developing follicles, and the expression of luteinizing hormone (LH) receptors on these granulosa cells. Under the influence of FSH, aromatase and p450 enzymes are activated, causing the granulosa cells to begin to secrete estrogen. This increased level of estrogen stimulates production of gonadotropin-releasing hormone (GnRH), which increases production of LH.[2][3] LH induces androgen synthesis by thecal cells, stimulates proliferation, differentiation, and secretion of follicular thecal cells and increases LH receptor expression on granulosa cells.[3] A granulosa cell is a supporting cell for the developing female gamete in the ovary of mammals. ...
Luteinizing hormone (LH) is a hormone synthesized and secreted by gonadotropes in the anterior lobe of the pituitary gland. ...
Aromatase belongs to the group of cytochrome P450 enzymes (EC 1. ...
Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ...
Estriol. ...
Gonadotropin-releasing hormone 1 (GNRH1 also called LHRH) is a peptide hormone responsible for the release of FSH and LH from the anterior pituitary. ...
Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ...
Estrogen surge Two or three days after LH levels begin to increase, one (or occasionally two) of the recruited follicles has emerged as dominant. Many endocrinologists believe that the estrogen secretion of the dominant follicle has increased to a level that GnRH production is suppressed, which lowers the levels of LH and FSH. This slowdown in LH and FSH production leads to the atresia (death) of most of the recruited follicles, though the dominant follicle continues to mature. Estrogen levels will continue to increase for several days (on average, six days, but this varies widely. The dominant follile is usually established by day seven of the cycle.[4]
These high estrogen levels initiate the formation of a new layer of endometrium in the uterus, histologically identified as the proliferative endometrium. Crypts in the cervix are also stimulated to produce fertile cervical mucus.[2] This mucus reduces the acidity of the vagina, creating a more hospitable environment for sperm.[5] It also has a characteristic texture that helps guide sperm through the cervix[6] and to the fallopian tubes, where they wait for ovulation.[7] In addition, basal body temperature may lower slightly under the influence of high estrogen levels.[8] The endometrium is the inner membrane of the mammalian uterus. ...
The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ...
The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ...
A spermatozoon or spermatozoan ( spermatozoa), from the ancient Greek σπÎÏμα (seed) and (living being) and more commonly known as a sperm cell, is the haploid cell that is the male gamete. ...
The Fallopian tubes, also known as oviducts, uterine tubes, and salpinges (singular salpinx) are two very fine tubes leading from the ovaries of female mammals into the uterus. ...
One of the many changes that take place in a womans body during her menstrual cycle is an increase in body temperature at the onset of ovulation. ...
LH surge and ovulation Estrogen levels are highest right before the LH surge begins. The short-term drop in steroid hormones between the beginning of the LH surge and the event of ovulation may cause mid-cycle spotting or bleeding.[9] The preovulatory LH surge starts the first meiotic division in oocytes and initiates luteinization of thecal and granulosa cells.[3] Ovulation normally occurs 30 (± 2) hours after the beginning of the LH surge (when LH is first detectable in urine).[10] For the figure of speech, see meiosis (figure of speech). ...
An oocyte or ovocyte is a female gametocyte that divides twice by mitosis and meiosis into two other oocytes or into two ootids. ...
Follicular waves The time from recruitment of tertiary stage follicles to ovulation is normally about two weeks, comprising days 1-14 of an idealized 28-day menstrual cycle. However, it is common for the follicular phase to last much longer, as sometimes no dominant follicle is selected. In this case, normally more tertiary stage follicles are recruited and the process begins again. One study of women with regular menstrual cycles found that none of them ovulated after the first wave of follicle development: 68% of cycles showed ovulation after the second wave, while 32% of cycles showed ovulation after the third wave.[11] Fertility awareness sources may refer to multiple waves of follicular development as a split peak because of the characteristic pattern of cervical mucus changes that is sometimes observed.[12] Fertility Awareness (FA) is the practice of observing one or more of a woman’s primary fertility signs to determine the fertile and infertile phases of her menstrual cycle. ...
References - ^ Bagnell, C (2005). "Animal Reproduction". Rutgers University Department of Animal Sciences.
- ^ a b c Weschler, Toni (2002). Taking Charge of Your Fertility, Revised Edition, New York: HarperCollins, pp.359-361. ISBN 0-06-093764-5.
- ^ a b c d Dee Unglaub Silverthorn (2004). Human physiology: an integrated approach, Third edition, San Francisco: Pearson/Benjamin Cummings, Chapter 26: Reproduction and Development, and Chapter 23 Endocrine control of growth and metabolism. ISBN 0-13-102015-3.
- ^ Stenchever Droegemuller Herbst Mishell (2001). Comprehensive Gynecology, Fourth edition, St. Louise, Missouri: Mosby, page 87. ISBN 0-323-01402-X.
- ^ Weschler (2002), p.57
- ^ Weschler (2002), illustrations p.59 and p.3 of color insert
- ^ Ellington, Joanna (2004). Sperm Transport to the Fallopian Tubes. Frequently Asked Questions with Dr. E. INGfertility Inc. Retrieved on 2006-08-13.
- ^ Weschler (2002), pp.54,306,310
- ^ Weschler (2002), p.65
- ^ Susan B. Bullivant, Sarah A. Sellergren, Kathleen Stern, et al (February 2004). "Women's sexual experience during the menstrual cycle: identification of the sexual phase by noninvasive measurement of luteinizing hormone". Journal of Sex Research 41 (1): 82-93. PMID 15216427.
- ^ Baerwald A, Adams G, Pierson R (2003). "A new model for ovarian follicular development during the human menstrual cycle.". Fertil Steril 80 (1): 116-22. PMID 12849812.
- ^ Weschler (2002), pp.131-2
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