Repro - Physiology Flashcards
How long does it take for the development of a mature spermatid?
2 months
Where does spermatogenesis occur in the testis?
In the seminiferous tubules
Put the following in order of their development during spermatogenesis: spermatozoan, primary spermatocyte, secondary spermatocyte, spermatid, and spermatogonium.
Spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid then spermatozoan
In spermatogenesis, what is the immature form of sperm called? What is the mature form called?
Spermatogonium; spermatozoan (remember: Gonium is going to be a sperm; Zoan is Zooming out of testis)
A spermatogonium has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
46; single chromosomes; diploid; 2N
A primary spermatocyte has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
46; sister chromatids; diploid; 4N
A secondary spermatocyte has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
23; sister chromatids; haploid; 2N
A spermatid has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
23; single chromosomes; haploid; N
What events define the process known as spermiogenesis?
The spermatid becomes a spermatozoan by losing cytoplasmic contents and gaining an acrosomal cap
During spermatogenesis, _____ undergoes meiosis I to form _____, whereas _____ undergoes meiosis II to form _____.
Primary spermatocyte; secondary spermatocyte; sperm
In males, follicle-stimulating hormone stimulates which cells? What is the resulting secretion?
Follicle-stimulating hormone stimulates Sertoli cells to produce androgen-binding protein and inhibin
In males, luteinizing hormone stimulates which cells? What is the resulting secretion?
Luteinizing hormone stimulates Leydig cells to produce testosterone
In male spermatogenesis, what is the effect of inhibin released by Sertoli cells?
Inhibin provides negative feedback of follicle-stimulating hormone release by the anterior pituitary
How does testosterone affect the hypothalamus-pituitary axis in the regulation of spermatogenesis?
Testosterone is necessary for sperm production in the testes but provides negative feedback on gonadotropin-releasing hormone and luteinizing hormone secretion in the hypothalamus and pituitary
Gonadotropin-releasing hormone from the hypothalamus stimulates the release of what two hormones from the anterior pituitary?
Luteinizing hormone and follicle-stimulating hormone
What are the functions of luteinizing hormone and follicle-stimulating hormone?
Follicle-stimulating hormone causes Sertoli cells to aid in Sperm production, whereas LH causes Leydig cells to release testosterone (also aiding sperm production)
Rank the following three androgens in order of potency: androstenedione, dihydrotestosterone, and testosterone.
Dihydrotestosterone > testosterone > androstenedione
What is the major source of dihydrotestosterone and testosterone in men?
The testis
What is the major source of androstenedione in men?
The adrenals
What enzyme converts testosterone to dihydrotestosterone?
5α-Reductase
What medication inhibits 5α-reductase?
Finasteride
What enzyme converts testosterone and dihydrotestosterone to estrogen in men? Where is this enzyme found?
Aromatase, which is found in adipose tissue and Sertoli cells
What effects does testosterone have during puberty?
Testosterone is responsible for the growth spurt (affecting the penis, seminal vesicles, sperm, muscle, and red blood cell development), deepening of the voice, increased libido, and closure of epiphyseal plates (ending linear growth)
Name three structures in which differentiation depends on testosterone during embryogenesis.
The epididymis, the vas deferens, and the seminal vesicles
How does testosterone cause epiphyseal plate closure in men?
Testosterone is converted to estrogen, which closes epiphyseal plates
What are the effects of dihydrotestosterone during male embryogenesis?
Differentiation of the penis, scrotum, and prostate
What are the effects of dihydrotestosterone on adult males?
Balding, prostate growth, and sebaceous gland activity
A bodybuilder comes to your office for infertility, and on exam you note small testicles; what is a likely cause of his infertility?
Azoospermia, caused by exogenous testosterone use resulting in hypothalamic-pituitary-gonadal axis inhibition and low intratesticular testosterone
Name four places in female body where estrogen is produced.
The ovaries (17β-estradiol), the placenta (estriol), the blood (aromatization), and the adipose tissue
Rank the following three forms of estrogen in order of potency: estradiol, estriol, and estrone.
Estradiol > estrone > estriol
What major hormone is produced by the granulosa cells?
Estrogen via conversion of androstenedione by aromatase
What major hormone is produced by the theca cells?
Androstenedione
What is the effect of follicle-stimulating hormone in granulosa cells?
Follicle-stimulating hormone promotes the conversion of androstenedione to estrogen via the aromatase enzyme
What is the effect of luteinizing hormone in theca cells?
Luteinizing hormone promotes the conversion of cholesterol to androstenedione via the enzyme desmolase
What effects does estrogen have on the uterus and ovaries?
Estrogen stimulates follicle growth and endometrial proliferation and increases myometrial excitability
What is the role of estrogen on physical development during puberty?
Genital and breast development and creation of female fat distribution
What is the effect of estrogen on the liver?
Increased synthesis of binding globulins and transport proteins
What is the effect of estrogen on the plasma lipid profile?
Increased high-density lipoprotein, decreased low-density lipoprotein
How does estrogen affect follicle-stimulating hormone and luteinizing hormone levels?
It provides negative feedback on follicle-stimulating hormone and luteinizing hormone secretion except near ovulation, when estrogen provides positive feedback for the luteinizing hormone surge
During pregnancy, what happens to the levels of endogenous estrogens?
There is a 50-fold increase in estradiol and estrone, and a 1000-fold increase in estriol
Which is an indicator of fetal well being during pregnancy, an increase in estradiol or estriol?
Estriol
What is the effect of estrogen on prolactin levels and function?
Estrogen increases prolactin secretion butblocks the action of prolactin at the breast
Name four places in the human body where progesterone is produced.
Corpus luteum, placenta, adrenal cortex, and testes
Progesterone causes what changes in the endometrium?
Spiral artery development and increased glandular secretions
What effect does progesterone have on pregnancy?
Progesterone maintains the pregnancy (remember: PROGESTerone is PRO-GESTation)
Progesterone _____ (increases/decreases) myometrial contractility whereas estrogen _____ (increases/decreases) myometrial contractility.
Decreases, increases
What is the effect of progesterone on cervical mucus?
Progesterone thickens cervical mucus to prevent sperm entry
Progesterone causes what effect on body temperature?
Increases body temperature; basal body temperature can be used to predict ovulation
What is the effect of progesterone on uterine smooth muscle?
It causes decreased myometrial contractility and smooth muscle relaxation
Progesterone levels are monitored daily during a woman’s menstrual cycle; what conclusion can you make upon noting an elevation in the progesterone level?
Progesterone elevation indicates that ovulation has occurred
What hormone stimulates endometrial proliferation during the menstrual cycle?
Estrogen
What hormone maintains endometrium to support implantation?
Progesterone; fertility is decreased without progesterone
When do luteinizing hormone levels peak during the menstrual cycle?
Luteinizing hormone levels peak just before ovulation
How long does the luteal phase of the menstrual cycle typically last?
14 days; therefore, ovulation day + 14 days = menstruation
How long does the follicular phase of the menstrual cycle typically last?
The follicular phase can vary in length, and this variation is what alters the length of the menstrual cycle
Estrogen levels peak _____ (after/before) ovulation, whereas progesterone levels peak _____ (after/before) ovulation.
Before; after
Does the graafian follicle mature during the follicular or luteal phase?
Follicular phase
Is the corpus luteum present during the follicular or luteal phase?
Luteal phase; the corpus luteum is formed from the ruptured follicle
Regression of the corpus luteum leads to what event?
Menstruation; when progesterone levels decrease the endometrial lining sloughs off
Put these events of the menstrual cycle in order: progesterone release from the corpus luteum, increase in luteinizing hormone secretion, menstruation, ovulation and increase in estrogen secretion.
Increase in estrogen secretion, increase in luteinizing hormone secretion, ovulation, progesterone release from the corpus luteum and menstruation
Oligomenorrhea is defined as a cycle lasting more than _____ days, whereas polymenorrhea is defined as a cycle lasting fewer than _____days.
35 days; 21 days
What is the difference between metrorrhagia and menometrorrhagia?
Metrorrhagia is frequent and irregular menstruation (often called spotting), whereas menometrorrhagia is irregular, heavy menstruation
A woman presents with pain in her right lower quadrant on the fourteenth day of her menstrual cycle, which is normally 28 days. After ruling out appendicitis, you determine this is caused by blood from a ruptured ovarian follicle at ovulation, also known as what?
Mittelschmerz; the blood from the ruptured follicle may cause peritoneal irritation that can mimic appendicitis
What happens following the luteinizing hormone surge in the normal menstrual cycle?
Luteinizing hormone surge stimulates the rupture of the follicle and ovulation
When does a primary 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 an oocyte arrested in between fetal life and ovulation?
Prophase (remember that meiosis I is in prOphase until Ovulation)
In what stage of meiosis II is a secondary oocyte arrested in between ovulation and fertilization?
METaphase (remember that an egg MET a sperm)
An oogonium is _____ (diploid/haploid) , _____ (2N/4N) and contains _____ (23/46) _____ (single chromosomes/sister chromatids/single chromatids).
Diploid; 2N; 46; single chromosomes
A primary oocyte is _____ (diploid/haploid), _____ (2N/4N) and contains _____ (23/46) _____ (single chromosomes/sister chromatids/single chromatids).
Diploid; 4N; 46; sister chromatids
A secondary oocyte is _____ (diploid/haploid), _____ (2N/4N) and contains _____ (23/46) _____ (single chromosomes/sister chromatids/single chromatids).
Haploid; 2N; 23; sister chromatids
An ovum is _____ (diploid/haploid), _____ (N/2N) and contains _____ (23/46) _____ (single chromosomes/sister chromatids/single chromatids).
Haploid; N; 23; single chromatids
What stage of oogenesis begins with an oogonium and ends with a primary oocyte?
Replication (interphase)
What stage of oogenesis begins with a primary oocyte and ends with a secondary oocyte and a polar body?
Meiosis I
What stage of oogenesis begins with a secondary oocyte and ends with an ovum and a polar body?
Meiosis II
Where does fertilization most commonly occur?
In the upper end of the oviduct (the ampulla)
When does fertilization occur in relation to ovulation?
Fertilization commonly occurs within one day of ovulation
When does implantation occur in relation to fertilization?
Implantation occurs 6 days after fertilization
When is β-human chorionic gonadotropin first detectable in the blood after conception? In the urine?
β-Human chorionic gonadotropin can first be detected in the blood 1 week after conception, and in the urine 2 weeks after conception
What is the source of β-human chorionic gonadotropin shortly following conception?
β-Human chorionic gonadotropin is secreted by trophoblasts
In which trimester does the β-human chorionic gonadotropin level peak?
In the first trimester; after the first trimester, the placenta becomes the source of progesterone so high β-human chorionic gonadotropin levels are not needed to maintain the corpus luteum
In pregnancy when do progesterone, estriol, and prolactin levels peak?
The levels increase throughout pregnancy
What process induces lactation? When does this occur?
The decrease in maternal hormones (estrogen) induces lactation after labor (recall that estrogen blocks the action of prolactin at the breasts)
Why is suckling necessary to maintain milk production?
Suckling stimulates nerves that induce increased oxytocin and prolactin levels
What are two roles of prolactin in the perinatal period?
Prolactin induces and maintains milk production and decreases reproductive function
What are two functions of oxytocin in the perinatal period?
Oxytocin increases milk letdown and is involved with uterine contractions
A woman has abnormally elevated human chorionic gonadotropin levels for her gestational age and you suspect gestational trophoblastic disease; name three examples of this disease.
Hydatidiform moles, choriocarcinoma, and gestational trophoblastic tumors
A woman presents to your office having missed her period 2 weeks ago; what noninvasive test can you perform to determine if she is pregnant?
A urinary human chorionic gonadotropin test can be used to detect early pregnancy
What is the role of human chorionic gonadotropin in the first trimester of pregnancy?
By acting like luteinizing hormone, human chorionic gonadotropin maintains the corpus luteum, which is the source of progesterone
During the second and third trimesters, where are human chorionic gonadotropin, estriol and progesterone produced?
The placenta
What physiologic process occurs as the number of ovarian follicles decrease with age?
The cessation of estrogen production resulting in menopause
What happens to levels of estrogen, luteinizing hormone, follicle-stimulating hormone, and gonadotropin-releasing hormone during menopause?
Estrogen decreases, whereas luteinizing hormone, follicle-stimulating hormone, and gonadotropin-releasing hormone increase
After 4-5 years of abnormal menstrual cycles, a 50 year-old woman presents with amenorrhea, pain during intercourse, and feelings of heat in her chest; what test would confirm the most likely diagnosis?
This is likely menopause, with amenorrhea, vaginal atrophy causing dyspareunia, and hot flashes; a serum follicle-stimulating hormone level will be greatly elevated
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 estrogen; 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, which may indicate premature ovarian failure
What are the clinical and pathologic manifestations of menopause?
Hirsutism, Hot flashes, Atrophy of the Vagina, Osteoporosis, Coronary artery disease (remember: menopause causes HHAVOC)
