| Question |
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| Answer |
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| gonadal development depends on what |
Y chromosome |
| how does the presence of a Y chromosome result in a male? |
sex-determining region Y gene (SRY) is present on the short arm of the Y chromosome and ecodes for a protein called the Testis Determining Factor (TDF). This protein induces the formation of the testes |
| primary sex structures |
ovaries, testes |
| development of secondary sex structures depends on |
presence or absence of the hormone testosterone |
| androgens |
testes secrete androgens and make male structures; ovaries can't secrete androgens resulting in female structures |
| wolffian ducts |
up unti the 7th week of development, embryos of each sex posses wolffian ducts (form internal male structures |
| mullerian ducts |
up unti the 7th week of development, embryos of each sex posses mullerian ducts (form internal female structures) |
| mullerian inhibiting factor |
causes regression of the mullerian ducts; females become females because of lack of mullerian inhibiting factor and testosterone |
| human chorionic gonadotropin |
hormone released by the placenta; stimulates early testicular secretion of testosterone which induces develpment of the wolffian ducts into the male reproductive tract (epididymis, ductus deferens, ejaculatory duct, and seminal vesicles) |
| male reproductive tract |
epididymis, ductus deferens, ejaculatory duct, and seminal vesicles |
| female reproductive tract |
oviducts, uterus, and vagina |
| external reproductive structures requre |
dihydtrotestosterone or DHT |
| genitalia are mostly formed after how many weeks |
16 |
| differentiation of the male and female brain also depends on the presence or absence of what |
testosterone |
| differences in male and female brain |
size of hypothalamic nuclei, cyclic release of gonadotropin, and sexual behavior |
| how long does puberty last |
3-5 years |
| menstruation started in 1840 at what age |
17 |
| sebaceous glands |
stimulated to secreted oil (acne) during puberty |
| progesterone |
female hormone related to menstruation period |
| precocious puberty |
early puberty; early development of secondary sex characteristics; caused by abnormal exposure of immature females to estrogen or males to androgens; often caused by tumors of the gonads or adrenal glands |
| delayed puberty |
menarche has failed to occur by age 17, testes failed to develop by age 20 |
| spermatogenesis works best in what temp |
colder |
| testes are divided into |
testicular lobules (250 compartments) |
| Each lobule in the teste contains |
a coiled seminiferous tubule and interstitial cells (Leydig cells) |
| function of seminiferous tubules |
produce sperm; they also contain Sertoli cells which play a role in nurturing the sperm cells |
| function of Leydig cells |
produce testosterone; are located outside of the seminiferous tubules |
| epididymis |
small coiled tube which measures about 20 feet, lies along the top and side of the testes; site of maturation of sperm |
| capacitation |
sperm's capacity to fertilize is enhanced by exposure to secretions of the female reproductive tract; the ductus epididymis also secretes "sperm forward-mobility protein," which causes a movement pattern of the sperm |
| vas deferens (ductus deferens) |
tubes that carry sperm from the epididmis up into the abdominal cavity to the ejaculatory duct near the bladder; at the end of the vas deferens is an expanded region called the "ampulla" which serves as a reservoir for sperm |
| vasectomy |
a small incision is made in the scrotum, the vas deferens is tied in two places and the segments between the ties are removed |
| Ejaculatory ducts |
carry sperm from vas deferens to urethra |
| urethra |
tube extending from the urinary bladder through the flor of the pelvic cavity and then through the penis; carries urine from bladder and sperm from ejaculatory duct |
| male sex accessory organs |
seminal vesicles, prostate gland, bulbourethral glands; these glands secrete seminal plasma which mixes with the sperm to form semen or seminal fluid |
| seminal vesicles |
secrete seminal plasma (more than half of total semen volume); fluid contains fructose to give energy to sperm; fluid also contains prostaglandins which stimulate contraction of the male and female reproductive tracts which helps in sperm transport |
| prostate gland |
lies below the bladder and is doughnut shaped; urethra pases through the small hole in the center; secretes alkaline fluid (13-33% of volume) that helps protect the sperm from the acidic environment of the male urethra and female vagina |
| bulbourethral glands |
secrete alkaline fluid, which acts as a lubricant |
| male fertility |
depends on quantity and quality of sperm; 2-6 ml, 20 million sperm/ml, 60% normal shape |
| number of sperm produced daily |
200 million/day |
| sperm live how long |
3-4 days |
| sperm count per ejaculation |
40 million to 250 million; below 20 million may mean infertility problems |
| how many sperm enter fallopian tube |
100-100,000 |
| how many sperm make it to the egg |
few hundred |
| zygote |
fertilized egg |
| what happens to dead sperm in female |
phagocytized by leukocytes |
| infertility is due to whom |
50% man 50% woman |
| structure of sperm |
head (contains nucleus with 23 chromosomes), acrosome (enzyme filled vesicle), tail (for movement), midpiece (contains a large number of mitochondria) |
| uterus |
pear shaped organ situated in the pelvic cavity above the urinary bladder and in front of rectum- 3 inches long, 2 wide, 1 thick; larger in multiparous women |
| two main regions of the uterus |
corpus or body, uterine isthmus or cervix (neck) |
| two main components of the wall |
endometrium (shed during menstruation) and myometrium (smooth muscle, contraction of the uterine wall results in expulsion of the fetus at birth |
| fallopian tubes, oviducts, or uterine tubes |
serve as ducts for ovaries (diameter of drinking straw); fertilization usually takes place there) |
| ovaries |
among the most vascular organs of the body |
| ovarian follicles |
female germ cells or oocytes are enclosed inside the ovary in tissue sacs called ovarian follicles |
| how many follicles do newborn girls have |
500,000 |
| how many follicles are released through ovulation |
400 |
| ovulation |
production of mature egg;when there is estrogen present, the immature oocyte will go from a primary, to secondary, to tertiary follicle. the large follicle that develops during the cycle is called a graafian follicle. It is this follicle that breaks ope |
| secretion |
production of female hormones |
| Estrogen |
estradiol, estrone, and estriol; estradiol is the principle estrogen; produced by follicle, corpus luteum, and plaenta, stimulates development of secondary sex structures, promote myometrial contractions, inhibit FSH secretion |
| progesterone |
produced by corpus luteum and placenta; stimulate development of secondary sex structures; inhibits contraction of uterine muscle |
| average human menstrual cycle length |
29.5 days |
| day 1 of ovarian cycle |
menstruation starts, estrogen and progesterone levels are low, FSH stimulates the development of the follicle (the egg inside the follicle), several follicles start to develop-follicle secrete estrogen |
| day 7 of ovarian cycle |
usually only one follicle continues to develop and secrete estrogens; others degenerate; estrogen elvels increase as the folicle grows into a graafian follicle;several days before ovulation, more LH are releases from anterior pituitary |
| day 14 of ovarian cycle |
high levels of LH stimulate ovulation; LH surge occurs 16 hours before ovulation; expulsion of egg from the mature follicle--ovaries usually alternate |
| indications of ovulation |
rise in basal body temperature due to progesterone; slight pain over ovary; vaginal secretory pattern |
| fertile period length |
4-6 days |
| destiny of follicle cell after ovulation |
LH stimulates the transformation of follicle cell into a corpus luteum (yellow body) |
| cells of corpus luteum secrete |
estrogens and progesterone |
| day 23 of ovarian cycle if pregnancy occurs |
the corpus persists; Human chorionic gonadotrophin (HCG) maintains the corpus luteum during pregnancy, which in turn maintains the levels of estrogen and progesterone |
| HCG |
human chorionic gonadotrophin; is detectable in the blood and urine as early as 8-10 days after fertilization so it's used in pregnancy kits; similar to GH and prolactin; has anti-insulin effects to divert glucose from mother to fetus |
| day 23 of ovarian cycle if no pregnancy |
corpus luteum begins to degenerate on about day 23 or 24; with degeneration of the corpus luteum, the levels of estrogens and progesterone drop |
| day 27 of ovarian cycle (no pregnancy) |
low levels of estrogen and progesterone cause ischemia in the endometrium, which initiates the beginning of the next cycle in one to two days |
| menstrual cycle names |
day 1-5 menstrual phase; 6-14 postmenstrual, preovulatory, or follicular phase; day 14 ovulation; day 14-27 premenstrual, postovulatory, or luteal phase; day 27-28 ischemic phase |
| implantation takes place how many days after fertilization |
6-7 days |
| intrauterin implantation |
usually implants in the upper posterior wall of uterus; cervical implantation |
| extrauterine implantation |
rare; called ectopic pregnancy (anywhere outside the uterus); tubal, abdominal, ovarian |
| pregancy lasts how long |
38 weeks (9.5 months) |
| pre-embryo |
first 2 weeks after conception |
| embryo |
3-8 weeks after fertilization; most critical period for damage to occur to baby |
| how much weight should a pregnant mother gain |
25 pounds |
| during pregnancy, which hormones increase |
estrogens, progesterone, HCG (human chorionic gonadotrophin which peaks at 2nd month), Glucocorticoids from the adrenal glands, T3 and T4 from thryoid, parathyroid hormone |
| change in pituitary during pregnancy |
increases in size and activity |
| change in blood volume and cardiac output during pregnancy |
increase |
| parturition |
act of giving birth |
| factors that increase contractibility of the uterus |
increased estrogen levels, secretion of oxytocin from posterior pituitary, formation of prostaglandins in the uterus |
| labor is divided into three stages |
1)cervical dilation-up to 10 cm 2)delivery of the baby 3)delivery of the placenta (afterbirth) |
| when does menopause start |
52 |
| menopause (what happens) |
follicle does not develop and therefore LH and FSH remain high and estrogens and progesterone remain low |
| treatment for menopause |
estrogen replacement therapy using premarin; there's recent evidence that ERT might not be so good |
| benefits of ERT |
relieves hot flashes, insomnia, vaginal dryness, mood swings, and heart disease |
| risks of ERT |
increased risk of endometrial and breast cancer, weight gain, and gall bladder disease |
| tubal ligation |
tying off both uterine tubes and thus preventing the transport of sperm or egg through the tubes |
Ch.18 LTI-MA 509
