Flashcards in 3b Oogenesis Ovulation Pregnancy Lactation hCG Menopause Spermatogenesi Androgens Deck (63):
When does a 1° oocyte undergo and complete meiosis I?
Meiosis I begins during fetal life and is completed just before ovulation
In what stage of meiosis I is a 1° oocyte arrested between fetal life and ovulation?
Prophase I (meiosis I is in prophase I until ovulation)
In what stage of meiosis II is a 2° oocyte arrested between ovulation and fertilization?
Metaphase II (an egg met a sperm)
A 16-year-old girl ovulates on day 14 of her menstrual cycle. What type of oocyte is released, and what happens if it is not fertilized?
2° oocyte, it degenerates if fertilization does not occur within 1 day
An oogonium is ____ (diploid/haploid) and ____ (2N/4N) and contains ____ (23/46) ____ (single chromosomes/sister or single chromatids).
Diploid, 2N, 46, single chromosomes
A 1° oocyte is ____ (diploid/haploid) and ____ (2N/4N) and contains ____ (23/46) ____ (single chromosomes/sister or single chromatids).
Diploid, 2N, 46, sister chromatids
A 2° oocyte is ____ (diploid/haploid) and ____ (1N/2N) and contains ____ (23/46) ____ (single chromosomes/sister or single chromatids).
Haploid, 1N, 23, sister chromatids
An ovum is ____ (diploid/haploid) and ____ (1N/2N), and contains ____ (23/46) ____ (single chromosomes/sister or single chromatids).
Haploid, 1N, 23, single chromatids
What stage of oogenesis begins with an oogonium and ends with a 1° oocyte?
Meiosis I beings with a(n) ____ and ends with a(n) ____ and ____ (choose from oogonium/1° oocyte/2° oocyte/ovum/polar body).
1° oocyte, 2° oocyte, polar body
In which stage of oogenesis does a 2° oocyte become an ovum and polar body? What happens to the first polar body (formed after meiosis I)?
Meiosis II; the first polar body can either degenerate or give rise to two polar bodies
A woman has transient abdominal pain on day 14 of her menstrual cycle. You determine she has just ovulated. What is this pain called?
Mittelschmerz (fallopian tube contraction and/or follicular swelling/rupture may cause peritoneal irritation that can mimic appendicitis)
What causes the luteinizing hormone surge, and what happens after the surge?
Estrogen surge causes luteinizing hormone surge, which then causes rupture of an ovarian follicle and ovulation
A woman ovulates. What happens to her temperature during ovulation?
Temperature is increased due to progesterone
To prepare for ovulation, increased estrogen levels cause ____ (upregulation/downregulation) of GnRH receptors on the anterior pituitary.
Where does fertilization most commonly occur?
In the upper end of the Fallopian tube (the ampulla)
A woman who is trying to conceive wants to know when fertilization occurs in relation to ovulation. What do you say?
Fertilization occurs within 1 day of ovulation
A woman who is trying to conceive wants to know when implantation occurs in relation to ovulation. What do you say?
Implantation in the wall of the uterus occurs 6 days after fertilization
In which trimester does the β-human chorionic gonadotropin level peak?
First trimester, after that the placenta becomes the source of progesterone
In pregnancy, when do progesterone, estriol, and prolactin levels peak?
The levels increase throughout pregnancy
A mother decides to breastfeed her baby because of the benefits she has read about. What process induces lactation? When does this occur?
The decrease in progesterone and estrogen levels disinhibits prolactin and induces lactation; after delivery
What are two functions of prolactin in the perinatal period? Two functions of oxytocin?
Prolactin induces/maintains milk production, decreases reproductive function; oxytocin increases milk let-down & causes uterine contractions
A mother wants to resume breastfeeding after having stopped for 1 month. Why is suckling necessary to maintain milk production?
Suckling stimulates nerves that induce increased oxytocin and prolactin levels
A woman wants to know what is considered the ideal nutrition for infants that are less than 6 months old. What do you tell her?
Breast milk, which contains maternal immunoglobulins (important for passive immunity, mostly IgA), macrophages, and lymphocytes
A woman wants to know the benefits of breastfeeding for her baby. What do you tell her?
It is associated with lower risk of infant infections and development of allergies, obesity, diabetes mellitus, and asthma for the child
A woman wants to know the benefits of breastfeeding for the mother. What do you tell her?
Breastfeeding is associated with a decrease in maternal risk of ovarian and breast cancer—it also facilitates mother-child bonding
A woman plans to only breastfeed her infant. What supplementation should you provide for the infant?
A 25-year-old woman takes a home pregnancy test, which is positive. What hormone does the pregnancy test detect, and where is it produced?
The home pregnancy test detects hCG, which is produced by the syncytiotrophoblast of placenta
A woman has very high hCG levels for gestation. Name four scenarios that could result in this observation.
Multiple gestations, hydatidiform moles, choriocarcinoma, and Down syndrome
A woman presents after having missed her period 2 weeks ago. What noninvasive test can you perform to determine if she is pregnant?
Urinary hCG test can be used to detect early pregnancy
What is the role of human chorionic gonadotropin (hCG) in the first trimester of pregnancy?
By acting like luteinizing hormone, hCG prevents abortion and maintains the corpus luteum, which is the source of progesterone
A woman is in her third trimester. What is the source of human chorionic gonadotropin, estriol, and progesterone during this period?
In the second and third trimesters, the placenta is the source (as the corpus luteum degenerates)
You order a human chorionic gonadotropin (hCG) pregnancy test. Does this test detect the α or β subunit of hCG?
The β subunit (the α subunit is structurally identical to LH, FSH, and TSH)
A woman has low human chorionic gonadotropin levels for gestation. Name three scenarios that could result in this observation.
Ectopic/failing pregnancy, Edwards syndrome, and Patau syndrome
In menopause, what happens to estrogen, LH, FSH, and GnRH levels?
Estrogen levels decrease, and LH, FSH, and GnRH levels increase
After 5 years of abnormal menses, a 50-year-old woman reports amenorrhea, dyspareunia, and hot flashes. Diagnosis? How do you confirm?
Diagnosis is menopause with amenorrhea, vaginal atrophy causing dyspareunia, and hot flashes; confirm with elevated serum FSH level
What is the average age for the onset of menopause in nonsmokers?
51 years; menopause occurs earlier in smokers
What is the main source of estrogen following menopause?
The peripheral conversion of androgens into estrone; increased androgens may cause hirsutism
A 35-year-old woman presents with amenorrhea, hot flashes, and a low bone mineral density. What diagnosis is likely?
She has symptoms of early menopause (prior to age 40), which may indicate premature ovarian failure
A 38-year-old female who has smoked for 15 years asks when she will reach menopause. Do you predict it will be before or after she turns 51?
Before, as she is a smoker (average age in nonsmokers is 51 years)
You suspect a woman is menopausal. What is the best serum test to confirm that menopause has occurred and why?
Check for significantly increased levels of follicle-stimulating hormone (FSH) (decreased estrogen reduces negative feedback on FSH)
You observe that women in menopause have decreased levels of estrogen. What is the cause of this phenomenon?
Age-linked decline in number of ovarian follicles causes a decrease in estrogen production
You suspect that a woman is approaching menopause. What is the most tell-tale sign of imminent menopause leading up to it?
4–5 years of abnormal menstrual cycles (menopause is usually preceded by these years)
How long does it take for the development of a mature spermatid? Where does this spermatogenesis occur?
2 months; in the seminiferous tubules
Put these in order from least to most developed: spermatozoon, 1° spermatocyte, 2° spermatocyte, spermatid, spermatogonium.
Spermatogonium, 1° spermatocyte, 2° spermatocyte, spermatid, spermatozoon (gonium is going to be a sperm, Zoon is Zooming to egg)
A spermatogonium has ____ (number) ____ (single chromosomes/sister chromatids), is ____ (diploid/haploid), and is ____ (4N/2N/1N).
46, single chromosomes, diploid, 2N
A 1° spermatocyte has ____ (number) ____ (single chromosomes/sister chromatids), is ____ (diploid/haploid), and is ____ (4N/2N/1N).
46, sister chromatids, diploid, 2N
A 2° spermatocyte has ____ (number) ____ (single chromosomes/sister chromatids), is ____ (diploid/haploid), and is ____ (4N/2N/1N).
23, sister chromatids, haploid, 1N
A spermatid has ____ (number) ____ (single chromosomes/sister chromatids), is ____ (diploid/haploid), and is ____ (4N/2N/1N).
23, single chromosomes, haploid, 1N
During spermatogenesis, ____ undergo meiosis I to form ____, whereas ____ undergo meiosis II to form ____.
1° spermatocytes, 2° spermatocytes, 2° spermatocytes, spermatids
A male patient is found to have impaired tail mobility of his sperm. What condition can this lead to, and which disease can cause this?
Infertility, which is seen in ciliary dyskinesia/Kartagener syndrome
When does spermatogenesis begin? What is spermiogenesis?
Begins at puberty with spermatogonia; spermatids lose their cytoplasmic contents and gain an acrosomal cap to form mature spermatozoon
What kind of barrier must the spermatogonia cross during the replication (interphase) stage of spermatogenesis?
The spermatogonia must cross the tight junctions of the blood-testis barrier in its journey to becoming a primary spermatocyte
Rank the following three androgens in order of most to least potent: androstenedione, dihydrotestosterone (DHT), and testosterone.
DHT, testosterone, and androstenedione
What is the major source of dihydrotestosterone and testosterone in men? Of androstenedione?
The testes; the adrenals (Androstenedione = Adrenal)
A 60-year-old man with benign prostatic hyperplasia takes a medication that inhibits 5α-reductase. Name the medication and its function.
Finasteride prevents conversion of testosterone to dihydrotestosterone by inhibiting 5α-reductase
Which enzyme converts testosterone and androstenedione to estrogen in men? Where is this enzyme found?
Cytochrome P-450 aromatase; adipose tissue and testes
A 14-year-old boy presents for an annual exam. He reports many changes since last year. What effects does testosterone have during puberty?
Growth spurt (penis, seminal vesicles, sperm, muscle, RBCs), deepening of the voice, increased libido, closure of epiphyseal plates
A man notices hair balding and increased sebaceous gland activity. He also has an enlarged prostate. What hormone causes these findings?
Dihydrotestosterone (also involved in differentiation of the penis, scrotum, and prostate early on in life)
A 57-year-old man has difficulty urinating and notices changes in his body. What are the effects of dihydrotestosterone on men?
Balding, prostate growth, sebaceous gland activity
A bodybuilder comes to your office for infertility; on exam, you note small testicles. What is a likely cause of his infertility?
Azoospermia due to exogenous testosterone use causing hypothalamic-pituitary-gonadal axis inhibition and low intratesticular testosterone
You noticed that the epiphyseal plate of a man has closed. What hormone causes this phenomenon?
Estrogen, converted from testosterone