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54 Cards in this Set
- Front
- Back
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How long does full sperm development take? When does it start?
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2 months - starts at puberty
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What does spermatogensis
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creates spermatids that undergo spermiogenesis
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What is the progression of sperm starting with a spermatogonium?
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Spermatogonium (diploid 2N, sex X-Y) - crosses blood testes barrier - under goes replication (interphase) - turns into primary spermatocyte (diploid 4N, sex X-X, Y-Y) - goes through meiosis I turns into secondary spermatocyte (haploid 2N, sex X-X and then Y-Y) - then undergo meiosis II turn into spermatid (haploid (N), sex, X, X, Y,Y) - undergo spermiogensis turn into spermatozoan
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What regulates spermatogenesis?
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hypothalamus releases GnRH signals the ant. pituitary to release LH and FSH
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What does LH do in a man?
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Stimulates the leydig cells to release testosterone (testosterone provides negative feed back on pituitary and hypothalamus)
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What does FSH do in a man?
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Stimulates the Sertoli cells to produce: Androgen binding protein, inhibin, produces anti-mullerian hormone
Inhibin provides negative feedback on ant. pituitary) |
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What are androgens? Where are they made?
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Testosterone (made in testis), dihydrotestosterone (DHT) (made in testis), androstendione (made in adrenal gland)
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What is the potency of the androgens?
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DHT>testosterone>androstnedione
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What does testosterone do?
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1. differentiation of epididymis, vas deferens, seminal vesicles (wolfian duct)
2. growth spurt: penis, seminal vesicles, sperm, muscle, RBCs 3. deepening of voice 4. closing of epiphyseal plates (via estrogen converted from testosterone) 5. libido |
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What are testosterone and androstenedione converted to in adipose tissue and sertoli cells?
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estrogen by aromatase
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What is the function of DHT?
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early: differentiation of penis, scrotum, prostate
late: prostate growth, balding, sebaceous gland activity |
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If a man takes exogenous steroids what will happen?
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will inhibit hypothalamus-pituitary-gondal axis - decrease intratesticular testosterone - decreased testicular size - azoospermia (no sperm)
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What is the source of estrogen?
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Ovary (17-B estradiol), placenta (estriol), blood (aromatization)
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What is the potencies of the different estrogens?
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estradiol>estrone>estriol
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What doest estrogen do in a female?
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1. development of genitalia and breast, female fat distribution
2. Growth of follicle, endometrial proliferation, increased myometrial excitability 3. Upregulation of estrogen, LH, and progesterone receptors; feedback inhibition of FSH and LH, then LH surge; stimulation of prolactin secretion (but blocks its action at breast) 4. increase transport of proteins, SHBG: increase HDL, decrease LDL |
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In pregnancy what values should you see for estrogen?
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50-fold increase in estradiol and estrone
1000-fold increase in estriol (indicator of fetal well-being) |
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What does LH stimulate in a woman?
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stimulates the theca cells - converts cholesterol into androstenedione (testosterone) via dsmolase - the androstenedione diffuses into the granulosa cell
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What does FSH stimulate in a woman?
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stimulates the granulosa cell - to convert androstenedione (from the theca cell) into estrogen via aromatase
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Where are estrogen receptors expressed?
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In the nuclei of cells
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Where does progesterone come from?
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corpus luteum, placenta, adrenal cortex, testes
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What is an elevation of progesterone indicative of?
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ovulation (PROGESTerone is PRO-GESTation)
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What does progesterone do?
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1. stimulation of endometrial glandular secretions and spinal artery development
2. maintenace of pregnancy 3. decrease myometrial exicitability 4. production of thick cervical mucus, which inhibits sperm entry into uterus 5. increase body temperature 6. inhibition of LH and FSH 7. uterine smooth muscle relaxation (preventing contractions) 8. decrease estrogen receptor expressivity |
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What does estrogen stimulate in the menstrual cycle?
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endometrial proliferation
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What does progesterone do in the menstrual cycle?
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maintains the endometrium to support implantation
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What stage in the menstrual cycle can vary?
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Follicular stage (the first one: usually is days 1-14), the luteal phase is always 14 days
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When is menstruation?
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ovulation day + 14 days
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oligomenorrhea
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>35 day cycle
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polymenorrhea
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<21 day cycle
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metorrhagia
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frequent but irregular menstruation
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menometrorrhagia
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heavy, frequent, irregular menstruation
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Basic outline of menstruation
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estrogen - LH - ovulation - progesterone (from corpus luteum) - menstruation (via apoptosis of endometrial cells)
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What does progesterone do in a woman?
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increases body temp - makes endometrium vasucular and secretory (so an egg can implant) the decrease in progesterone causes menstruation
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Mittelschmerz
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blood from ruptured follicle (during ovulation) causes peritoneal irritation that can mimic appendicitis
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What is the progression of immature egg to mature egg?
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ogonium (diploid 2N) - undergoes replication (interphase) and becomes a primary oocyte (diploid 4N) - undergoes meiosis I to form secondary oocytes (haploid 2N) - goes through meiosis II to become ovum (haploid N)
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What stage is the egg arrested in until ovulation?
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prophase I of meiosis I
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What stage is the egg arrested in until fertilization?
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metaphase II of meiosis II
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When do primary oocytes begin meiosis?
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during fetal life - they complete meiosis I just prior to ovulation ( they are arrested in prophase I until they are ovulated)
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If fertilization does not occur what happens to the egg?
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the secondary oocyte degenerates
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Where does fertilization typically occur? when?
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Often occurs in the ampulla of the fallopian tubes, happens within one day of ovulation
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When does implantation of the egg into the uterus happen?
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6 days after fertilization. Trophoblasts secrete B-hCG, which is detectable in the blood 1 week after conception and on home test in urine 2 weeks after conception
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When is B-hCG release in the blood and in the urine?
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1 week after implantation you can detect it in the blood
2 weeks after implantation you can detect it in the urine (will test positive on home pregnancy tests) |
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When does lactation happen?
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estrogen and progesterone stimulate breast development during pregnancy - prolactin levels stedily increase during pregnancy - after labor estrogen and progersterone levels drop quickly (after placenta is delivered) so the drop in estrogen and progresterone in the presence of high prolactin and lactation occurs - lactation is maintained by suckling, which stimulates oxytocin and prolactin secretion
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What is lactation maintained by?
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suckling (nerve stimulation) - lactation increases prolactin and oxytocin
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What does prolactin do?
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induces and maintains lactation and decreases reproductive function (why you "cannot" get pregnant while breast feeding)
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What does oxytocin do?
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helps with milk letdown and may be involved with uterine contractions
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What is the source of hCG?
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from the syncytitrophoblast of the placenta
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What is the function of hCG?
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1. maintains the corpus luteum (and thus progesterone) after implantation - by acting like LH (otherwise no luteal stimulation and abortion results). In the 2nd and 3rd trimester the placenta synthesizes its own estriol and progesterone and the corpus luteum degenerates
2. used to detect pregnancy because it appears early in the urine 3. elevated hCG appears in pathologic states (hydatiform moes, choriocarcinoma, gestational trophoblastic tumors) |
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What is happens during menopause?
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decrease in estrogen production due to age-linked decline in number of ovarian follicles - average age of onset if 51 (earlier in smokers)
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What is the average age of onset of menopause?
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51 - but it is earlier in smokers
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What are the hormonal changes see in menopause?
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decreased estrogen, increased FSH, LH, increased GnRH
*The increased FSH is used as a confirmatory test |
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What is used as a confirmatory test for menopause?
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increased FSH
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What usually precedes menopause?
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4-5 years of abnormal menstrual cycles. Source of estrogen (estrone) after menopause becomes peripheral conversion of androgens. Increased androgens cause hirsutism
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What are symptoms of menopause?
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HHAVOC
hirsutism, hot flashes, atrophy of the vagina, Osteoporosis, Coronary artery disease |
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What can early menopause indicate?
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premature ovarian failure
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