Possible Answers: Hypothalamus. Correct answer: Anterior pituitary gland. Explanation : The anterior pituitary gland produces both FSH and LH, two hormones that play key roles in the menstrual cycle. Example Question 6 : Understanding Reproductive Functions.
Possible Answers: Fertilization. Explanation : At the midpoint of the day menstrual cycle, ovulation occurs. Example Question 7 : Understanding Reproductive Functions. Possible Answers: leydig cells. Correct answer: leydig cells. Explanation : Testosterone is synthesized by Leydig cells.
Example Question 8 : Understanding Reproductive Functions. Possible Answers: ovulatory phase. Correct answer: follicular phase. Explanation : The menstrual phase is divided into two halves—the first 14 days are involved in follicular maturation, and is thus known as the follicular phase, while the last 14 days involve the degneration of the corpus luteum, and is thus known as the luteal phase.
Example Question 9 : Understanding Reproductive Functions. Which hormone maintains the corpus luteum during pregnancy? Possible Answers: Estradiol. Correct answer: Human chorionic gonadotropin HCG. Explanation : The corpus luteum is what remains of the folliclle after ovulation. Example Question 10 : Understanding Reproductive Functions. Which is the correct sequence through which sperm leave the male body during ejaculation?
Possible Answers: Testes epididymis vas deferens urethra. Correct answer: Testes epididymis vas deferens urethra.
Explanation : Sperm are produced in the testes. Copyright Notice. View Tutors. Erin Certified Tutor. Kimberly Certified Tutor. Michael Certified Tutor. Report an issue with this question If you've found an issue with this question, please let us know.
Do not fill in this field. Louis, MO Or fill out the form below:. Company name. After the increase seen over the first weeks of gestation, luteal secretion of progesterone , and relaxin declines. Sampling of the ovarian vessels at cesarean section and the observation that progesterone levels rise in response to hCG administration postpartum confirm continued secretion of progesterone and relaxin by the corpus luteum at term and beyond.
This is in contrast to the central role of the corpus luteum in the maintenance of pregnancy in species such as rodents, in which luteolysis itself is the initiator of parturition. Mol Endocrinol , Endocr Rev , Am J Obstet Gynecol , Acta Endocrinol , Spirtos NJ, Foote C, Downing J, et al: Evaluation of the preovulatory rise of follicle stimulating hormone and progesterone in normally ovulating women of reproductive age. Int J Fertil , Eramaa M, Tuuri T, Hilden K, Ritvos O: Regulation of inhibin alpha and beta A-subunit messenger ribonucleic acid levels by chorionic gonadotropin and recombinant follicle-stimulating hormone in cultured human granulosa-luteal cells.
Fritz S, Kunz L, Dimitrijevic N, et al: Muscarinic receptors in human luteinized granulosa cells: Activation blocks gap junctions and induces the transcription factor early growth response factor Fritz S, Wessler I, Breitling R, et al: Expression of muscarinic receptor types in the primate ovary and evidence for non-neuronal acetylcholine synthesis.
Corner G: The histologic dating of the human corpus luteum of menstruation. Am J Anat , Crisp TM, Channing CP: Fine structural events correlated with progestin secretion during luteinization of rhesus monkey granulosa cells in culture. Biol Reprod , J Endocrinol , Sugino N, Kashida S, Takiguchi S, et al: Expression of vascular endothelial growth factor and its receptors in the human corpus luteum during the menstrual cycle and in early pregnancy.
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Mol Hum Reprod , N Engl J Med , Ashar SA, Menon KMJ: Receptor-mediated gonadotropin action in the ovary: Rat luteal cells preferentially utilize and are acutely dependent upon the plasma lipoprotein supplied sterols in gonadotropin stimulated steroid production. J Biol Chem , Sekar N, Garmey JC, Veldhuis JD: Mechanisms underlying the steroidogenic synergy of insulin and luteinizing hormone in porcine granulosa cells: Joint amplification of lipoprotein LDL receptor, steroidogenic acute regulatory StAR protein and cytochrome P side-chain cleavage pscc enzyme.
Mol Cell Endocrinol , J Cell Biol , Pearce RB, Crunshaw J, Holmes WN: The fine structure of the interrenal cells of the duck Anas platyrhynchos with evidence for the possible exocytotic release of steroids.
Cell Tiss Res , Steroids , Prostaglandins , Recent Prog Horm Res , Science , Contraception , Hutchison JS, Zeleznik AJ: The rhesus monkey corpus luteum is dependent on pituitary gonadotropin secretion throughout the luteal phase of the menstrual cycle. Mais V, Kazer RR, Cetel NS, et al: The dependency of folliculogenesis and corpus luteum function on pulsatile gonadotropin secretion in cycling women using a gonadotropin-releasing hormone antagonist as a probe. Messinis IE, Bergh T, Wide L: The importance of human chorionic gonadotropin support of the corpus luteum during human gonadotropin therapy in women with anovulatory infertility.
Fertil Steril , J Clin Endocrinol Metab A, J Endocrinol R11, J Endocrinol R21, J Mol Endocrinol , Mol Cell Endocrinol R15, Acta Obstet Gynecol Scand , Ann Intern Med , Guraya SS: Morphology, histochemistry, and biochemistry of human ovarian compartments and steroid hormone synthesis.
Physiol Rev , Reprod Fertil Dev , Obstet Gynecol , Baird DT, Backstrom T, McNeilly AS: Effect of enucleation of the corpus luteum at different stages of the luteal phase of the human menstrual cycle on subsequent follicular development.
J Reprod Fertil , Balasch J, Creus M, Fabregues F, et al: Midluteal immunoreactive alpha inhibin serum concentrations as markers of luteal phase deficiency. Horm Res 37 suppl 1 , Clin Endocrinol , Maruncle M, Casper RF: The effect of luteal phase estrogen antagonism on luteinizing hormone pulsatility and luteal function in women.
Zeleznik AJ, Little-Ihrig LL: Effect of reduced luteinizing hormone concentrations on corpus luteum function during the menstrual cycle of rhesus monkeys. Concentrations throughout the luteal phase of the menstrual cycle and early pregnancy J Endocrinol , Changes in available luteinizing hormone and chorionic gonadotropin-binding sites in macaque luteal membranes during the nonfertile menstrual cycle Endocrinology , Semin Reprod Endocrinol , Endocrine , Auletta FJ, Flint APF: Mechanisms controlling corpus luteum function in sheep, cows, nonhuman primates, and women especially in relation to the time of luteolysis.
Ann N Y Acad Sci , Biochem Biophysical Res Comm , Sotrel G, Helvacioglu A, Dowers S, et al: Mechanism of luteolysis: Effect of estradiol and prostaglandin F2 on corpus luteum luteinizing hormone human chorionic gonadotropin receptors and cyclic nucleotides in the rhesus monkey. Anderson LL: Effects of hysterectomy and other factors on luteal function.
J Clin Endocrinol , Adv Prostaglandin , Johansson EDB: Inhibition of the corpus luteum function in women taking large doses of diethylstilbestrol. Butler WR, Hotchkiss J, Knobil E: Functional luteolysis in the rhesus monkey: Ovarian estrogen and progesterone during the luteal phase of the menstrual cycle.
Blumenfeld Z, Nahhas F: Luteal dysfunction in ovulation induction: The role of repetitive human chorionic gonadotropin supplementation during the luteal phase. Br J Obstet Gynaecol , Yuan W, Giudice LC: Programmed cell death in human ovary is a function of follicle and corpus luteum status.
Sugino N, Suzuki T, Kashida S, et al: Expression of Bcl-2 and Bax in the human corpus luteum during the menstrual cycle and in early pregnancy: Regulation by human chorionic gonadotropin. Stouffer RL, Hodgen GD: Induction of luteal phase defects in rhesus monkeys by follicular fluid administration at the onset of the menstrual cycle. J Reprod Fertil 36 suppl :1, Ottobre JS, Houmard BS, Ottobre AC: Luteal production of steroids and prostaglandins during simulated early pregnancy in the primate: Differential regulation of steroid production by chorionic gonadotropin.
Csapo AI, Pulkkinen M: Indispensability of the human corpus luteum in the maintenance of early pregnancy luteectomy evidence. Obstet Gynecol Surv , Following this peak, levels of human chorionic gonadotrophin fall although they remain detectable throughout pregnancy. Once the placenta is established, it becomes the main source of progesterone production around week 12 of pregnancy , and human chorionic gonadotrophin is no longer required to maintain ovarian function.
However, human chorionic gonadotrophin may have additional beneficial effects in the latter stages of pregnancy; such roles are currently being investigated by researchers. There is no strong evidence that high levels of human chorionic gonadotrophin cause direct negative consequences. Very high levels of human chorionic gonadotrophin are rare but can indicate hyper-proliferation of the placenta also referred to as hydatidiform moles or molar pregnancies , which can lead to cancer choriocarcinomas in some cases.
Levels of human chorionic gonadotrophin may also be elevated sometimes in association with some non-pregnancy related cancers e. Low levels of human chorionic gonadotrophin can indicate a failing pregnancy.
Reduced levels of human chorionic gonadotrophin are often observed in ectopic pregnancies where the embryo implants outside of the uterus or in miscarriages.
About Contact Events News. LH directly stimulates the secretion of progesterone from small luteal cells via activation of the protein kinase A second messenger pathway. Large luteal cells are of granulosal cell origin and contain receptors for PGF 2alpha and appear to mediate the luteolytic actions of this hormone. If pregnancy does not occur, the corpus luteum must regress to allow follicular growth and ovulation and the reproductive cycle begins again.
Luteal regression is initiated by PGF 2alpha of uterine origin in most subprimate species.
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