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93 Cards in this Set

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Identify the gonads in both sexes. State their two fundamental functions: gametogenesis and production of sex hormones. Understand the general pattern of reproductile control in both males and females. Know the stages in the control of reproductive function.
Gonads: testes in men; ovaries in women

Functions:

1. produce reproductive cells or gametes (gametogenesis) spermatozoa or ova
2. produce steroid hormones or sex hormones or gonadal steroids: testosterone (androgen); estradiol and progesterone

Key points:

1. GnRH is a hypophysiotropic hormones secreted by the hypothalamus
2. it reaches the anterior pituitary via the hypothalamic-pituitary portal vessels
3. the brain is the main regulator of reproduction
4. release of GnRH is pulsatile
5. the anterior pituitary releases pituitary gonadotropins (follicle stimulating hormone (FSH) and luteinizing hormones (LH)). Named for their effects in females but structures identical in both sexes. Effe cts:

a. maturation of sperm or ova
b. stimulation of sex hormone secretion whic affect all portions of reproductive system.

These gonadal steroids also exert feedback secretion of GnRH, FSH and LH. Inhibin from gonads also affects anterior pituitary.

* Each Link is important: hypothalamus, anterior pituitary and gonads.

Stages:

1. during the initial stage, which begins during fetal life and ends in the first year of life (infancy), GnRH, the gonadotropis, and gonadal sex hormones are secreted at relatively high levels.

2. From infancy to puberty, the secretion rates of these hormones are very low, and reproductive function is quiescent.

3. Beginning at puberty, hormonal secretion rates increase markedly, showing large cyclical variations in women during the menstrual cycle. This ushers in the period of active reproduction.

4. Finally, reproductive function diminishes later in life, largely because the gonads become less responsive to the gonadotropins. The ability to reproduce ceases entirely in women.
Describe the sequence of events in gametogenesis. Identify when mitotic division of germ cells occur in males and females.
Developing gametes are called germ cells and undergo either mitosis or meiosis. Similarities and differences exist between mailes and females.

The first stage in gametogenesis is proliferation of the primordial germ cells by mitosis. 23 pairs of chromosomes or a total of 46. In mitosis, the 46 chromosomes are duplicated to produce daughter cells with 46 chromosomes identical to the original cell. In females, mitosis of germ cells occurs in fetal development. In males, some occurs in the embryo but most during puberty.

The second stage is meiosis in which each gamete receives only 23 chromosomes from a 46-chromosome germ cell - one from each homologous pair.
Recognize that the genetic difference between males and females is the difference in one chromosome.
Sex determination is established at the time of fertilization. Genderl determination is decided by genetic inheritance of two chromosomes called the sex chromosomes. The larger one is the X chromosome and the smaller the Y chromosome. Males have one X and one Y and females have to X's. Thus the genetic difference between male and female (genotype) is the difference in one chromosome.

The ova can contribute only one X chromosome whereas the half of the sperm produced are X and half are Y. At union, 50% have XX and 50% have XY. A simple test can be used to determine a person's sex using a scraping from cheek or even white blood cells: when two X's are present, one is non-functional and forms a nuclear mass termed the sex chromatic (Barr Body) which is observable with light microscopy. A better method is to look at all chromosomes in cell culture (Karyotyping).
Describe the methods by which one's genetic sex (and general chromosome composition) can be determined.
The ova can contribute only an X chromosome whereas the half that the sperm produce are half X and half Y. At union, 50% have XX and 50% have XY. A simple test can be used to dtermine a person's sex using a scraping from a cheek or even white blood cells: when two X's are present, on is non-functional and forms a nuclear mass termed the sex chromatic (Barr Body) which is observable with light microscopy. A better method is to look at all chromosomes in cell culture (Karyotyping).
Describe the general functions and understand the importance of the SRY gene.
This multiple step process in the development of the reproductive system = sex differentiation.

Phenotype = sexual appearance/function may be abnormal even though genotype (normal XX and XY's. Somewhere along the line, sexual differentiation is atypical. Genes only determine whether an individual has testes or ovaries. The rest of sexual differentiation depends on the presence or absence of substances produced by the gonads, in particular the testes.

Male and female gonads originate from urogenital ridge and until the 6th week, the primordial gonads are undifferentiated. In the genetic male, the testes begin to develop in the 7th week due to the SRY (sex-determining region on Y chromosome). Without a Y chromosome, there is no SRY and thus no development of testes and thus at about 11 weeks, the ovaries develop. There is no crossing over of X and Y chromosomes except at the tips where the SRY is NOT located. Thus the male determining gene does not get into the female genome.
Describe the sequence of events that occurs in the male reproductive system after the testes begin to differentiate. Know the sequence of events that occurs in the female reproductive system after testes do not develop. Recognize that the female is the "default" sex.
Early on there is a double genital duct system (before functioning fetal gonads). There are the Wolffian ducts and the Mullerian ducts and a common opening for the genital ducts and the urinary system. Normally, only one progresses - in the male, the Wolffian duct persists and the Mullerian ducts regresses. In the female, the Wolffian duct regresses and the Mullerian duct persists. How does this occur?

The testes produces testorerone from the Leydig cells and Mullerian-inhibiting substance (MIS) from the Sertoli cells. SRY induces the expression of MIS which causes the Mullerian duct to regress. Simultaneously, testosterone causes the Wolffian ducts (of the male) to develop into the epididymis, vas deference, ejaculatory duct and the seminal vesicles. Later the penis forms and the testes descend into the scrotum (2 degrees temperature less than in the abdomen).

The female does not have testosterone or MIS, so the Mullerian duct developes into the fallopian tube and uterus. Without testosterone, the Wolffian ducts regress and the rest of the female reproductive system develops. Ovaries do not play a role in these development processes. Female development will occur unless stopped by factors from testes.
Describe the anatomy of the male reproductive system.
Two testes, system of ducts tat store and transport sperm to the exterior and glands which empty into ducts and the penis. (Ducts, glands and penis = accessory reproductive organs).

Scrotum-sac which contains the testes and is outside the abdomen since the testes descended into the scrotum at the 7th month of gestation. 2-3 degrees C lower temperature required for sperm formation.

Spermatogenesis occurs in the tiny convoluted seminiferous tubules which have a total length of 250 meters. The tubular wall has developing germ cells. The spermatozoa are in the fluid filled lumen. The wall contains developing germ cells and Sertoli cells (important in spermatogenesis). The Leydig cells or interstitial cells lie between the walls in the interstitium. Leydig cells produce testosterone.

The seminiferous tubles in this testis are apparent in the area that has been cut away. Spermatozoa move from the tubles into rete testis and then into the epididymis, first into the efferent ductules and then into the vas deferens. The seminiferous tubles from the vast network converge at the rete testis which then connect with the efferent ductules and empty into the single duct in the epididymis (vas deferens). The vas deferens and the blood vessels and nerves are in the spermatic cord which passes through a slitlike passage, the inguinal canal, in the abdominal wall.

The two vas deferens, one from each testis, lead to the back of the urinary bladder. The seminal vesicle ducts and the ejaculatory ducts connect and the latter pass through the prostate gland and join the urethra within the penis. Paired bulbourethral glands lying below the prostate gland drain into the urethra.

Prostate gland and sminal vesicles secrete the majority of fluid in which sperm is suspected. The sperm plus fluid = semen.

Bulborethral glands contribute a small amount of lubricating mucus secretion. The glandular secretions are:

- nutrients
- buffers for protecting sperm against acidic vaginal secretions
- chmicals which increase sperm motility
- prostaglandins
Describe the two functions performed by the testes in male reproductive physiology. Explain the reason for the location of the testes in the scrotum. Identify the site of sperm formation and the location of the Leydig cells.
The testes produce testosterone from the Leydig cells and Mullerian-inhibiting substance (MIS) from Sertoli cedlls. SRY induces the expression of MIS which causes the Mullerian duct to regress. Simultaneously, testosterone causes the Wolffian ducts (of the male) to develop into the epididymis, vas deferens, ejaculatory duct and seminal vesicles. Later the penis forms and the testes descend into the scrotum (2 degrees temperature less than in abdomen)
Describe the stages of spermatogenesis. Understand that spermatogenesis also involves returning undifferentiated spermatogonia to the spermatogonium pool, which keeps the number available for spermatogenesis high throughout a man's life. Describe the structure of mature sperm.
Spermatogenesis is the testicular process in adult males that generates haploid gametes capable of fertilizing ova. The overall result is that the set of 23 pairs of homologous chromosomes is reduced to a set of 23 chromosomes per sperm - the corresponding 23 pairs are present in ova.

Spermatogonia or undifferentiated germ cells begin to divide at puberty. The daughter cells of this first division divide repeatedly. Eventually, at the last mitotic division, primary spermatocytes are produced which then undergo the meiotic division. Note that many of the results of the cloning revert back to spermatogonia to be recycled so that the supply of undifferentiated spermatogonia does not decrease.

The primary spermatogonia increase in size and undergoes the first meiotic division to form two secondary spermatocytes with each containing 23 chromosomes and then these divide again producing spermatids. One primary spermatocyte -> 4 spermatids with 23 chromosomes and 1 chromatid per chromosome instead of 2.

The final stage is differentiation of the spermatid into the spermatozoa. No more cell division but lots of changes to the cell such as elongation.

After it's release in the female reproductive tract, a spermatozoan is propelled by the thrashing movements of its flagellum. At the time of fertilization, the acrosome at the head of an individual spermatozoan releases enzymes that allow it to gain access to the interior of the ova and accomplish the union of genetic material.

The head contains mainly the nucleus of the cell with the genetic material (DNA). The tip is the acrosome which is a protein filled vesicle with several enzymes. The tail is the flagellum which are contractile filaments that produce a whiplike motion which propels the sperm at a velocity of 1-4 mm/minute. The mitochondria is contained in the midpiece and provides the energy. The entire process takes about 64 days, from primary spermatocyte to sperm. A normal male produces about 30,000,000 sperm per day.
Describe the functions of Sertoli cells in spermatogenesis.
We identified the Leydig cells as important in producing testosterone. The Sertoli cells in the wall of the tubles play key roles in the entire process.

Basement membrane surrounds the seminferous tuble. Tight junctions separate Sertoli cells which extend from basement membrane to lumen. The ring of interconnectied Sertoli cells froms the blood-testes barrier or the Sertoli cell barrier which prevents movement of chemicals from blood to lumen. This unique arrangement of the Sertoli cells allow sfor different environments as the germ cells develop.

Sertoli cells are the route for arrival of nutrients to developing germ cells and they also provide much of the gluid found in the lumen. It also contains androgen-binding protein (ABP) which binds to testosterone and crosss the tight junctions to enter the lumen thus keeping testosterone levels high in the lumen. Sertoli cells also secrete variety of chemical messengers which act to stimulate proliferation and differentiation of the germ cells. Sertoli cells also secrete inhibin which inhibits FSH secretion from the anterior pituitary.
Describe the functions of the epididymis, vas deferens, seminal vesicles, prostate gland and bulbourethral glands. Describe the pathway tranversed by sperm from seminigerous tubules to the exterior of the body.
The pathway for sperm to follow is seminiferous tubles, rete testies, efferent ducts into the epididymis, vas deferens (the epididymis and vas deferens serve a storage function). The movement of sperm to the epeididymis results from the build up of pressure in the ducts from the fluid secreted by the Sertoli cells. The sperm are normally not motile at this time.

Through the epididymis, the concentration of sperm increases due to absorption of fluid and the movement is by peristatltic motion created by contractions of the smooth muscle of the epididymis and vas deferens.
Describe the neural control of erection and ejactulation. Describe the role of the sympathetic nervous system in these relfexes.
The penis has three cylindrical vascular regions running along the entire length. The small arteries supplying these tissues are normally somewhat constricted so less volume of blood is in these compartments. However, when sexual excitation occurs, these vessels dilate the vascular regions engorge and interestingly, the venous outflow is compressed by the engorged tissue so that the engorgement is possible. The vascular tone is due to sympathetic nervous system but during sexual excitement, the SNS is inhibited AND the neurons release nitric oxide which also relaxes the arterial smooth muscle. Higher centers and local mechanoreceptors are involved.

Erectile dysfunction or impotence is the inability to achieve or keep an erection. 10% of males between 40 and 70 have complete erectile dysfunction and with age it increases due to many causes including:

- malfunction of efferent and afferent nerves or decending pathways
- atherosclerosis/diabetes
- alcohol
- psychological factors such as depression

Treatment: phosphodiesterase type 5 (PDE5) inhibitors such as Viagra, Levitra and Cialis. Remember the most important part of an erection - increased blood flow to the area due to release of nitric oxide. PDE5 inhibits the blocking of the enzyme which breaks down cGMP which leads to the vasodilation. Thus if there is more cGMP there is more blood flow.

Ejaculation: discharge of semen from the penis. During ejaculation, the urethra at the base of the urinary bladder is closed so sperm does not enter the bladder nor can urin be expelled. Erection involves relaxation of the arteries while ejaculation involves contraction of the smooth muscles of the ductal system.
Discuss the roles of GnRH, FSH and LH in controlling male reproductive functions. Describe how their secretion is controlled by secretions from the testes.
Neuroendocrine cells of GnRH fire bursts to release GnRH every 90 minutes.

FSH and LH released at these times from same cells but in unequal amounts. FSH acts on Sertoli cells to simulate spermatogenesis whereas LH acts on Leydig cells which stimulate testosterone secretion which has many systemic effects but testosterone also acts to stimulate Sertoli cells to also facilitate spermatogenesis (indirect affect of LH).

Negative feedback: FSH and LH secreted by same cells in anterior pituitary but their secretion rates are altered differently by negative feedback mechanisms.

Testosterone inihibits LH by:

1. acting on hypothalamus to decrease GnRH
2. acting on the anterior pituitary to decrease LH secretion in response to GnRH

Inhibin from the Sertoli cells inhibits FSH secretion. Thus FSH stimulates spermatogenesis and inhibin from Sertoli decreases FSH release.

Amazingly compared to females, GnRH, LH, FSH, testosterone and inhibin are relatively constant from day to day.
Describe the functions - both endorcrine and paracrine - of testosterone in the male.
1. Required for initiation and maintenance of spermatogenesis (acts via Sertoli cells)

2. Decreases GnRH secretion via an action on the hypothalamus

3. Inhibits LH secretion via a direct action on the anterior pituitary

4. Induces differentiation of male accessory reproductive organs and maintains their function

5. Induces male secondary sex characteristics; opposes action of estrogen on breast growth

6. Stimulates protein anabolism, bone growth and cessation of bone growth

7. Required for sex drive and may enhance aggressive behavior

8. Stimulates erythropoietin secretion by the kidneys
Define puberty and describe the secondary sex characteristics of the male. Recognize the contribution of adrenal androgens to the onset of puberty. Describe the endocrine changes that promote further sexual maturation.
Puberty - the period during which reproductive organs mature and reproduction is possible. In males, this is usually between 12 and 16.

Secondary sex characteristics: armpit hair, growth spurt, etc.

Signs of early puberty due to adrenal androges from ACTH and then hypothalamic-anterior pituitary-gonadal axis
Describe the anatomy of the female reproductive tract.
The female anatomy includes two ovaries, two fallopian tubes, the uterus, cervix and vagina (all except the ovaries are considered female reproductive tract. These are the internal genitalia. The urinary and reproductive tracts of females are separate unlike the male.
List the stages of oogenesis. Recognize that the primary oocytes are in meiotic arrest from fetal life until puberty. Compare and contrast oogenesis and spermatogenesis in terms of both time frame and end results.
Oogenesis is the production of the ovum or egg. At birth, there are between 2-4 million eggs and no new ones appear after birth. Only a few (400 approximately) will be ovulated. Others degenerate so that at around 50 years of age, few remain. One implication is that eggs ovulated later in life are 35-40 years older than those ovulated at puberty, thus defects in them may have occurred.

No new germ cells are produced in the fetus after about 7 months of gestation however, there is some thought that ovaires may be able to generate new oogonia after birth.

During fetal development, the primary oocytes are prorduced which then begin the first meiotic division by replicating the DNA but then they are in meitic arrest until puberty when only those primary oocytes destined for ovulation will complete this first meitic division. The secondary oocyte and a polar body are produced (the latter has little cytoplasm and is nonfunctional). The second meiotic division occurs in the fallopian tube after ovulation but only if the egg is fertilized. Notice that each primary oocyte produces one ovum where as primary spermatocytes produce 4 viable spermatozoa.
Describe the progression of follicles from primordial to late antral and dominant. Recgonize that atresia is the fate of the overwhelming majority of primordial follicles.
Eggs exist in structures known as follicles during their life in the ovary.

Following the development of the oocyte from the primordial follicle identifying granulosa cells, zona pellucida, thecal cells, the antrum, cumulus oophorous, and the graafian follicle (mature follicle).

The primordial follicle surrounded by a single layer of granulosa cells develop by proliferation of the granulosa cells into many layers and by increasing size of oocyte and by separation of the inner granulosa cells from the out layers by the zona pellucida.

Granulosa cells secrete estrogen, some progesterone and inhibin.

Gap junctions within zona pellucida allows nutrients and chemicals to pass to oocyte. For example, the granulosa cells produce factores which keep primary oocytes in meiotic arrest.

Theca cells around the layers of granulosa cells develop and play a role in the estrogen secretion by the granulosa cells. Soon after this development, a fluid filled space develops (antrum) - fluid produced by the granulosa cells.

At the beginning of the menstrual cycle, about 15-25 of the preantral and early antral follicles are present and these develop into larger follicles. Now anothe rprocess comes into play to develop one of these follicles into the "dominant" follicle and the others in both ovaries regress (atresia or the process of programmed cell death (apoptosis)). 99% of the follicles present at birth undergo atresia.

When the dominant folicle develops due to the increased fluid, granulosa cells project into the antrum (cumulus oophorous). When ovulation approaches, the primary oocyte completes its first meiotic division to become a secondary oocyte and the cumulus oophorous separates and the egg floats free in the antrum. This mature follicle (graafian follicle) is now about 1.5 cm in diameter and bulges on the surface of the ovary. Enzymatic digestion allows ovulation to occur on or about day 14 - usually one ovum but obviously, multiples can occur.
Describe the events that precede and accompany ovulation, including the formation of a corpus luteum. Recognize that the ovarian cycle can be divided into two phases - the follicular and the luteal, and that the boundary between them is ovulation.
Once the mature follicle releases the fluid and the egg, the wall collapses around the antrum and a rapid transformation occurs. The granulosa cells enlarge and the glandlike structure which forms is the corpus luteum. The corpus luteum secretes estrogen, progesterone and inhibin. If fertilization does not occur, the corpus luteum will regress and this regression leads to menstruation and a new cycle.

The ovarian cycle of changes in steroid production drives the rest of the changes that characterize the menstrual cycle of adult females.

Follicular vs. Luteal
---------------------
The follicular phase is marked by increasing levels of estrogens whereas the luteal phase is one of increased progesterone levels; the transition between the two is ovulation.
Identify the hormones that are produced by the ovaries and the cells that produce them. Identify the hormones of the anterior pituitary that influence ovarian hormone secretion. Describe the pattern of the changes of all these hormones during a menstrual cycle. Compare granulosa cells to Sertoli cells, and state the ways theca cells are analygous to Leydig cells.
Sites of synthesis:
-------------------

- estrogen - granulosa cells during follicular development and after ovulation by the corpus luteum

- progesterone - granulosa cells and thecal cells before ovulation but major source is corpus luteum

- inhibin - granulosa cells and corpus luteum

Control of function:
--------------------

Lots of similarities to testicular function - GnRH (hypothalamus), FSH and LH from the anterior pitiuitary and estrogen and progesterone from the ovaries.

Similar to the male, pulses of GnRH occur but these pulses change over the course of the menstrual cycle and the responsiveness of the anterior pituitary to GnRH and of the ovaries to FSH and LH change.

Plasma concentrations during menstrual cycle:
---------------------

Ovulation is provoked by a surge in LH and marks the transition to the luteal phase of the cycle, characterized by high levels of progesterone.

Eventually, a decrease in LH leads to luteolysis and the withdrawal of steroid support for a thick, active uterus.

Small increases in the secretion of gonadotropins (LH and FSH) lead to follicular maturation, including an increase in the synthesis and secretion of ovarian steroid hormones.

- FSH - early increase with decline except for small midcycle peak

- LH - stable during follicular development but then "LH surge" 18 hours before ovulation and then a rapid decrease and then slow decline

- estrogen - low for the first week and then rises during the second week as the dominant follicle grows and secretes estrogen. The second spik after ovulation is from the corpus luteum

- progesterone - small amounts released by the ovaries during the follicular stage and right after ovulation, the corpus luteum releases large amounts

- inhibin - now shown but pattern similar to estrogen
Describe the hormonal control of ovarian functions during the early and middle follicular phases of the menstrual cycle, including the various actions of estrogen.
a
Discuss how ovarian hormones regulate the plasma concentrations of gonadotropins during the early and middle follicular phase. Explain that the increasing plasma concentration of estrogen during the late follicular phase stimulates the LH surge that is necessary for ovulation. This is one of the most confusing concepts to understand in physiology - that the same hormone can have negative-feedback effects at (relatively) low concentration and positive-feedback effects at high concentration. It can be helpful to describe experimental evidence that shows that the two effects are real:

1. At menopause, when plasma estrogen levels become very low, plasma gonadotropin concentrations are very high - a classical example of escape from negative feedback; and

2. One can mimic the events of the late follicular phase (i.e., an LH surge) by injecting/infusing appropriate amounts of estrogen during the early follicular phase.

However, the exact mechanisms underlying these puzzling phenomena are simply not known yet.
a
Describe the effects of the LH surge on ovulation and the formation of the corpus luteum.
1. The primary oocyte completes its first meiotic division and undergoes cytoplasmic changes that prepare the ovum for implantation should fertilization occur. These LH effects on the oocyte are mediated by messengers released from the granulosa cells in response to LH.

2. Antrum size (fluid volume) and blood flow to the follicle increase markedly.

3. The granulosa cells begin releasing progesterone and decrease the release of estrogen, which accounts for the midcycle decrease in plasma estrogen concentration and the small rise in plasma progesterone just before ovulation.

4. Enzymes and prostaglandins synthesized by the granulosa cells break down the follicular-ovarian membranes. These weakened membrances rupture allowing the oocyte and its surrounding granulosa cells to be carried out onto the surface of the ovary.

5. The reamining granulosa cells of the ruptured follicle (along with the theca cells of that follicle) are transformed into the corpus luteum which begins to release progesterone and estrogen.
Describe the effects of the sex steroids and inhibin on gonadotropin secretion during the luteal phase.
a
Discuss the hormonal control of the corpus luteum. Understand why its fate depends upon whether pregnancy occurs during the cycle in which it is produced.
a
Describe the phases of the menstrual cycle in terms of events occurring in the uterus. Correlate these phases with the follicular and luteal phases of the ovarian cycle.
The phases of the uterine cycle can be described also relative to uterine events (menstrual, proliferative and secretory).

- Uterine changes during the cycle are a result of changes in estrogen and progesterone.

- Estrogen during the proliferative stage stimulates endometrial growth and underlying muscle (myometrium) and causes the synthesis of progesterone receptors in the endometrium.

- Progesterone from the corpus luteum acts on estrogen primed endometrium to convert it into a secretory tissue which is ideal for implantation of fertilized ovum.

- Progesterone inhibits myometrial contractions by opposing estrogen and locally generated prostaglandins (purpose: ensures that fertilized ovum is not swetp away before implantation). Progesterone also has a role in preventing premature delivery

- Estrogen produces a thin mucus by the cervix which makes for easier sperm movement.

- Progesterone produces a mucus plug which helps prevent bacteria from entering the uterus and affecting the fetus if conception occurs.

- The drop in progesterone and estrogen deprives the endometrium of hormonal support and in addition causes vasoconstrictuion which causes then sloughing of cells. Uterine contractions also occur due to prostaglandins. (Cramps (dysmenorrhea) are usually due to overproduction of the prostaglandins which cause contractions of the uterus. Contractions of other smooth muscles elsewhere lead to nausea, vomiting and headache.)

- After initial constriction of blood vessels, the vessels dilate causing the hemorrhange and the discarding of the endometrial debris.
Describe the hormonal control of the events in the uterine cycle.
a
Describe the uterine events that are associated with menstruation.
Day(s)

1-5: Estrogen and progesterone are low because the previous corpus luteum is regressing

7: A single follicle (usually) becomes dominant

7-12: Plasma estrogen increases because of secretion by the dominant follicle.

7-12: LH and FSH decrease due to estrogen and inhibin negative feedback

12-13: LH surge is induced by increasing plasma estrogen

14: Ovulation is mediated by follicular enzymes and prostaglandins

15-25: Corpus luteum forms and under the influence of low but adequate levels of LH, secretes estrogen and progesterone and so plasma concentrations of these hormones increase

25-28: Corpus luteum degenerates (if egg is not fertilized)
Describe the effects of estrogen and progesterone on sex accessory organs and secondary sex characteristics and understand their effects on other tissues.
Estrogen:

1. Stimulates growth of ovary and follicles (local effects)

2. Stimulates growth of smooth muscle and proliferation of epithelial linings to reproductive tract. In addition:
a. fallopian tubes: increases contractions and cilliary activity
b.
Describe the sources and effects of andogen in women.
Androgens are normally present in women due to normal production by adrenal glands and ovaries. They play roles in stimulation of pubic hair, axillary hair, skeletal muscle development and sex drive. Excessive androgens cause virilism which is characterized by dissipation of fat distribution, presence of beard, body hair, low pitched voice, enlarged muscle mass, enlarged clitoris and diminished breast size.
Describe the secondary sex characteristics in females and the hormonal changes that cause them.
a
Discuss the importance of adipose tissue to the timing of puberty.
Adipose tissue hormone leptin stimulates the secretion of FnRH and this explains the relationship between body stores of fat and onset of puberty. Girls that exercise extensively, are delyaed. Puberty is a gradual change over several years as evidenced by slowing rising levels of gonadotropins and testosterone/estrogen.

GnRH and estrogen are secreted in low levels during childhood and thus logically there is no follicular maturation or no menstrual cycle. The female accessory sex organs remain undeveloped and nonfunctional and minimal secondary sex characteristics. Puberty occurs when brain function changes and GnRH increases which in turn stimulates pituitary gonadotropins which stimulate follicular development and estrogen secretion.
Describe how the egg is transported into the uterine tube after ovulation. Identify the site of fertilization of the egg.
The egg once ovulated is swept into the entrance of the fallopian tube because of the ciliated epithelium in combination with the smooth muscle of the fimbriae. The egg can take up to 4 days to reach the uterus so fertilization has to take place in the fallopian tube because of the short viability of the unfertilized egg.
Describe how sperm are transported in the female reproductive tract. Recognize the importance of capacitation of sperm function.
Within a minute or so after intercourse, some sperm can be detected in the uterus. The watery mucus induced by estrogen aids the transport of the sperm to the cervix. The acidic environment of the vagina contributes to a high mortality rate for sperm and the sperm also die because of the long trip and energy requirements. Why is the vagina acidic? aids against yeast and bacterial infections. The sperm's motility in combination with uterine contractions propel the sperm toward the fallopian tubes.

Of the original several hundred million sperm, only about 100 or so reach the fallopian tube. Sperm cannot fertilize the egg until after residing in the female tract for several hours. This process, called capacitation results in:

1. a more whiplike action of sperm tails compared to the wavelike beats

2. sperm plasma membrane becomes altered so that it can fuse with surface membrane of the egg
Describe the events that take place during fertilization. Understand the importance and describe the mechanisms that prevent polyspermy.
The sperm move through the granulosa cells and penetrate the zona pellucida whose proteins function as sperm receptors since head of sperm has the proteins which bind to the receptors. This binding triggers the acrosome reaction which results in altering of the sperm head so that enzymes can digest the zona pellucida and enter into the cytoplasm of the egg. The newly fertilized egg is called a zygote and the continued viability of the egg is dependent on no further entrance of sperm. This is called "block to polyspermy" which is a reaction that changes the membane characteristics so that no more sperm can penetrate the egg. The receptors for sperm are inactivated and the zona pellucida is hardened. The fertilized egg completes it's second meiotic division within a few hours and the second polar body is extruded and then disintegrates. Nuclei of sperm and egg unite and fertilization is complete. If fertilization is unsuccessful, the egg disintegrates and is phagocytized by the lining of the uterus.

Ectopic pregnancies are the abnormal embedding of a fertilized egg in the fallopian tube or abdominal cavity. Major risk of maternal hemorrhage results.
Recognize that the conceptus undergoes cleavage as it passes down the uterine tube. Know when, with respect to ovulation, implantation (nidation) takes place. Identify the stage of the conceptus at implantation.
Conceptus - collective term for everything ultimately derived from fertilized egg. The conceptus remains in the fallopian tube for three to four days since estrogen maintains the contraction of the smooth muscle near where the fallopian tube enters the wall of the uterus. When progesterone levels rise, the contractions relax and the conceptus passes. Cleavage in the meantime has taken place via mitotic cell division and the 16 to 32 cell conceptus which reaches the uterus is the same size as the original fertilized egg. Any of these cells are totipotent meaning they could develop into an entire individual - monozygotic vs. dizygotic.

Once in the uterus, conceptus floats in the uterine fluid for about 3 days during which it undergoes further cell division until it becomes a blastocyte and is no longer totipotent and the cells are not differentiating.

The blastocyte has an outer area called the trophoblast, an inner cell mass and a central fluid filled cavity. The inner cell mass gives rise to the developing embryo during the first two months and a fetus thereafter. The trophoblast surrounds the embryo/fetus and is involved in its nutrition and secretion of hormones.

The zygote develops into the blastocyte during the 14-21 day period of the menstrual cycle when the uterus is being prepared by progesterone (corpus luteum) to receive the blastocyte. By the 21st day (7 days after ovulation), implantation begins (imbedding). The trophoblast cells are sticky especially near the inner cell mass and here is where the adhesion to the endometrium occurs. Communication between the endometrium and the inner cells mass augments the implantation.

The initial nutrients are provided by the endometrial cells during the first few weeks but soon the placenta takes over.
Describe the structure of the placenta. State its major functions with regard to supplying the fetus with nutrients and removing wastes. Understand that it accomplishes these functions without allowing mixing of fetal and maternal blood.
The placenta is a combination of interlocking fetal and materinal tissues that provides the exchange between the mother and fetus for the remainder of gestation.

The fetal portion of the placenta is supplied by the other portion of the trophoblast cells, the chorion, and the maternal portion comes from the endometrium under the chorion. The fingerlike projections of the trophoblast cells are the chorionic villi and these contain the network of capillaries and surrounded by the sinus or pool of blood from the mother.

After the end of the first trimester, the placenta is more fully developed, including its nutritive/exchange relationship between the maternal and fetal circulations, and its steroid products provide hormonal support for the uterus.

The maternal blood supplies the sinuses via the uterine artery and the blood exists via the uterine vein. Blood flows from the fetus into the villi vessels via the umbilical arteries and out of the villi back to the fetus via the umbilical veins. The umbilical vessels are in the umbilical cord. There is obviously exchange of materials between the two blood streams, but no mixing of blood.

By five weeks after implantation, the placenta is well established and the fetal heart is pumping blood.

Soon an amniotic cavity forms between the inner cell mass and the chorion. The amnion or amniotic sac with the amniotic fluid in the cavity helps buffer mechanical injury and temperature changes. Amniocentesis is the technique used for sampling amniotic fluid as early as the 16th week using a needle and syringe.

During the first trimester, the chorion is the source of gonadotropin hormone that maintains the steriod production by the corpus luteum in the ovary.

The placental steroidogenesis provides direct steroidal support of the uterus during the second and third trimesters: the shift between these steroid sources is a critical transition in a successful pregnancy.
List the hormones secreted by the placenta. Appreciate that it first rescues the corpus luteum, allowing that microorgan to continue secreting progesterone and estrogen, and later takes on steroidogenesis itself. Identify the source of androgends for placental estrogenesis.
Estrogen and progesterone levels increase during pregnancy. Progesterone inhibits uterine contractions so that premature delivers are less likely. Corpus luteum is the source for these hormones during the first two months. Once pregnancy occurs, the corpus is maintained by human chorionic gonadotropic (HCG) from the trophoblast cells during implantation. The presence of this hormone is the basis for the common pregnancy test. Thus, the signal that maintains pregnancy comes from the conceptus not the mother's tissue. HCG drops substantially at about two months at which time the placenta secretes large amounts of estrogen and progesterone.

Why is there no menstruation during pregnancy? GnRH, FSH and LH are powerully inhibited by the presence of estrogen and progesterone. Many hormones are secreted by the placenta including human placental lactogen which mobilizes fat, stimulated glucose production and stimulates breast development.
Describe the major maternal responses to pregnancy. Understand that hypertension is not a normal response to pregnancy.
placenta - secretion of estrogen, progesterone, human chorionic gonadotropin, inhibin, human placental lactogen and other hormones

anterior pituitary - increased secretion of prolactin; secretes very little FSH and LH

adrenal cortex - increased secretion of aldosterone

posterior pituitary - increased secretion of vasopressin

parathyroids - increased secretion of parathyroid hormone

kidneys - increased secretion of renin, erythropoietin, and 1,25-dihydroxyvitamin D; retention of salt and water due to increased aldosterone, vasopressin and estrogen

breasts - enlarge and develop mature glandular structure due to estrogen, progesterone, prolactin and human placental lactogen

blood volume - increased due to total erythrocyte volume increased by erythropoietin and plasma volume by salt and water retention. However, plasma volume usually increases more than red cells, thereby leading to small decreases in hematocrit

bone turnover - increased due to increased parathyroid hormone and 1,25-dihydroxyvitamin D

body weight - increased by average of 12.5 kg, 60% of which is water

circulation - cardiac output increases, total peripheral resistance decreases (vasodilation in uterus, skin, breasts, GI tract and kidneys), mean arterial pressure stays constant

respiration - hyperventilation occurs (arterial pressure of CO2 decreases) due to the effects of increased progesterone

organic metabolism - metabolic rate increases; plasma glucose, gluconeogenesis and fatty acid mobilization all increase due to hyporesponsiveness to insulin due to insulin antagonism by the human placental lactogen and cortisol

appetite and thirst - increased; particularly after the first trimester

nutritional RDAs - increased

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Eclampsia is a serious condition in about 5-10% of the pregnancies characterized by edema, protein in the urin and hypertension. Descreased growth rate and even fetal death can occur. Abnormal constriction of the maternal blood vessels and poor implantation resulting in poor blood flow to the placenta may be important in this condition.
Recognize that plasma estrogen levels continue to increase as term approaches, and that the progesterone/estrogen ratio decreases. Know the changes that this decreasing ratio has on the myometrium and cervix as term approaches.
At the time of parturition some changes obviously occur. The high levels of estrogen cause the smooth muscle cells to synthesize connexin which form gap junctions between the muscle cells leading to coordinated contractions of the uterus. The cervix which was fairly rigid due to its collagen make up now becomes soft and flexible due to the enzymatic breakup of its collagen fibers. Extrogen also stimulates the synthesis of receptors for the posterior pituitary hormone, oxytocin, on the myometrium for contraction stimulation.
Identify the stages of parturition. Understand the positive-feedback characteristics of parturition. Describe the effects of estrogen, oxytocin and prostaglandins on myometrial contractions.
Gestation is 40 weeks from the last day of the menstrual cycle or 28 weeks from conception. Survival is possible at 24 weeks of pregnancy, but often with significant deficits to the infant.

At the time of parturition, some changes obviously occur. The high levels of estrogen cause the smooth muscle cells to synthesize connexin which forms gap junctions between the muscle cells leading to coordinated contracts of the uterus. The cervix, which was fairly rigid due to its collagen makeup now become soft and flexible due to the enzymatic breakup of its collagen fibers. Estrogen also stimulates the synthesis of receptors for the posterior pituitary hormone, oxytocin, on the myometrium for contraction stimulation.
Describe the structure of the female breast and understand how it changes during puberty, pregnancy and lactation. Identify the hormones that are responsible for these changes. State the significance of parturition initiating lactation. Describe the reflexes that allow for milk synthesis and milk ejection.
Alveoli are the sites of milk secretion and are surrounded by contractile cells called myoepithelial cells. The breast tissue is stimulated by high levels of estrogen, progesterone, prolactin and human placental lactogen. (Prolactin is from the anterior pituitary.) Changing blood concentrations of estrogen and progesterone during the menstrual cycle causes smaller fluctuations in breast tissue than occurs during pregnancy naturally.

Prolactin is the major hormone stimulating production of milk but is in the presence of estrogen and progesterone, milk production does not occur. Thus at delivery, these inhibitory influences are removed. Even though basal levels of prolatin decrease after birth, there are pulses of prolactin during each nursing cycle.

Reflexes mediating the surges of prolactin are initiated by the afferent input to the hypothalamus from the nipple receptrs stimulated by suckling which inhibit the neurons from the hypothalamus which release dopamine.

Another reflex is essential for nurings. Mile may be secreted into the alveoli but in order to get the milk, the milk ejection reflex must occur (also called milk let down). The myoepithelial cells surround the alveoli and contract under the influence of oxytocin from the posterior pituitary when suckling occurs. Higher centers are involved too and cause more or less milk let down.

Suckling also inhibits the hypothalamic-pituitary-ovary axis which blocks ovulation. Prolactin probably blocks GnRF release. Ovulation can be delayed for years with suckling - natural birth control but is not always effective.

Colostrum is the watery fluid secreted after delivery and then in about 24-48 hours, milke secretion begins. Colostrum is rich in protein and antibodies and other factors important in the immune systems (some present in milk as well). Low gastric acidity of the newborn and the greater permeability of the intestinal epithelium facilitates the entry of proteins into the blood of the newborn.
Describe the major methods available for contraception and how they work.
Oral contraceptions - based on the fact that estrogen and progesterone can inhibit gonadotropin release which prevents ovulation. Other factors may also inhibit fertilization such as changes in the cervical mucus toward less viscous and less proliferation of the endometrium.

RU486 or mifepristone - used within 72 hours after intercourse - this drug has antiprogresterone because it binds with these receptors but doesn't activate them and thus the endometrium erodes and the fallopian tubes and myometrium contract
Early in development (4 months after fertilization), the testes:

a. are found in the abdominal cavity (peritoneal cavity)
b. have moved through the inguinal canal
c. produce a membrane which becomes the scrotum
d. produce sperm
e. all of the above
a. are found in the abdominal cavity (peritoneal cavity)
The site of final maturation and storage of sperm cells before their ejaculation is the:

a. seminal vesicles
b. seminiferous tubules
c. penis
d. epididymis
e. sperm bank
d. epididymis
The site of spermatogenesis in the male is the

a. ductus deferens
b. seminiferous tubules
c. epididymis
d. rete testis
e. efferent ductile
b. seminiferous tubules
LH in the male stimulates

a. development of the seminiferous tubules
b. spermatogenesis
c. testosterone production
d. both a and b
e. all of the above
c. testosterone production
Which of the following factors causes a decrease in GnRH release?

a. decreased inhibin
b. increased testosterone
c. decreased FSH
d. decreased LH
b. increased testosterone
Which of these is consistent with erection of the penis?

a. decreased activity of the sympathetic nervous system
b. dilation of arterioles to the penis
c. compression of the veins from the penis
d. engorgement of the sinusoids of the penis with blood
e. all of the above
e. all of the above
After ovulation, the mature follicle collapses, taking on a yellowish appearance to
become the

a. degenerating follicle
b. corpus luteum
c. inner cell mass
d. granulosa cells
e. theca cells
b. corpus luteum
The major secretion from the mature follicle is

a. estrogen
b. progesterone
c. androgen
d. LH
e. FSH
a. estrogen
Development of normal female internal and external genitalia requires

a. Mullerian-inhibiting substance
b. expression of the SRY gene
c. insensitivity to circulating testosterone
d. complete absence of testosterone
e. absence of a Y chromosome
e. absence of a Y chromosome
Which is NOT characteristic of a normal postpubertal male?

a. Inhibin from the Sertoli cells decreases FSH secretion.
b. Testosterone has local effects on the Sertoli cells.
c. Testosterone stimulates GnRH from the hypothalamus.
d. Testosterone inhibits LH secretion.
e. GnRH from the hypothalamus is release in pulses.
c. Testosterone stimulates GnRH from the hypothalamus.
Menopause is characterized primarily by

a. primary ovarian failure
b. loss of estrogen secretion from the ovary due to a decrease in LH
c. loss of estrogen secretion from the ovary due to a decrease in FSH
d. a decrease in FSH and LH due to increase inhibin
e. a decrease in FSH and LH due to a decrease in GnRH pulses
a. primary ovarian failure
The seminal vesicles and prostate gland are important to males because:

a. as sperm pass through them, the sperm are matured and attain fertilizaing
capacity
b .they provide an environment in which meiosis can be completed
c. they cause the acrosomes on sperm to fall off
d. their secretions provide nutrients for sperm and fluid for the ejaculate
e. they store large numbers of sperm
d. their secretions provide nutrients for sperm and fluid for the ejaculate
What is in vitro fertilization and what is a common reason for its use?

a. fertilization within the ovarian follicle; used in women who fail to ovulate
b. fertilization outside the body; used to alleviate certain types of infertility in
males or females
c. fertilization of an egg by another egg; used experimentally to produce XY
females
d. fertilization of an egg by sperm from another species; used only in animals
e. fertilization in the oviduct; used when sperm numbers are very low
b. fertilization outside the body; used to alleviate certain types of infertility in
males or females
What specific problem would be faced by a sperm that never developed an acrosome, but was otherwise normal.

a. getting through the zona pellucida
b. it would not be able to bind to the zona pellucida
c. failure to generate ATP to support motility
d. traveling through the epididymis
e. inability to "swim"
a. getting through the zona pellucida
In which of the following situation would you expect to see very high blood
concentrations of luteinizing hormone?

a. following a week of daily injections of testosterone
b. after immunization against gonadotropin-releasing hormone
c. after hysterectomy (removal of the uterus)
d. following vasectomy
e. in a situation where all Leydig cells were destroyed
e. in a situation where all Leydig cells were destroyed
The most fertile time of the 'textbook' menstrual cycle is roughly between:

a. days 1-3
b. days 7-10
c. days 13-16
d. days 24-30
e. days 45-48
c. days 13-16
What is the principle and accepted use of amniocentesis?

a. to diagnose the sex of offspring
b. to diagnosis fetal genetic disease
c. to add nutrients to amniotic fluid
d. to induce abortion
e. to treat fetal genetic diseases
b. to diagnosis fetal genetic disease
Which of the following statements about the oviduct is FALSE ?

a. it is a hostile environment for sperm
b. the embryo resides in this location for its first few days
c. the embryo implants in the oviduct
d. it is lined by ciliated epithelial cells
e. it is the location where fertilization normally occurs
c. the embryo implants in the oviduct
Which of the following structures in the genital tract of the fetus is “programmed to
die,” but in roughly half the population is rescued and allowed to develop by the
action of a steroid hormone?

a. ovarian ducts
b. gonads
c. Wolfiaan ducts
d. Mullerian ducts
e. hypothalamus
c. Wolfiaan ducts
What is the chemical being tested for in the common pregnancy testing kit readily
available?
a. progesterone
b. inhibin
c. estrogen
d. human chorionic gonadotropin
e. combination of progesterone and estrogen
d. human chorionic gonadotropin
In women, the hormone _____________, which is produced by the __________,
prevents regression of the corpus luteum following conception.

a. LH, anterior pituitary
b. HCG, embryo
c. gonadotropin releasing hormone; hypothalamus
d. gonadotropin releasing hormone; endometrium
e. HCG; ovarian follicle
b. HCG, embryo
Which of the following events is observed in spermatogenesis, but NOT in
oogenesis?

a. a phase in which the “gonia” cells become stuck for years in mitosis
b. two meiotic cell divisions
c. mitotic proliferation of cells prior to meiosis
d. constant renewal of the cells which become gametes
e. loss of all mitochondria before forming a mature gamete
a. a phase in which the “gonia” cells become stuck for years in mitosis
Which of the following events permits a sperm to digest its way through the zona
pellucida?
a. binding to the surface of the oocyte
b. acrosome reaction
c. cortical reaction
d. extrusion of polar body
e. whip like action of spermatozoon tail.
b. acrosome reaction
The pathway of a sperm between initial formation and ejaculations is: testes->

a. vas deferens->epididymis->urethra
b. vas deferens->seminal vesicle->epididymis
c. epididymis->vas deferens->urethra
d. epididymis->ureter->vas deferens->urethra
e. epididymis->prostate->vas deferens->urethra
a. vas deferens->epididymis->urethra
The epididymis is important to the male reproductive function because it:

a. acts as a heat exchange mechanism to regulate sperm temperature..
b. is the source of sperm stem cells (i.e. spermatogonia).
c. is the site where the acrosome reaction occurs.
d. prevents defective sperm from passing through urethra
e. allows sperm to mature and acquire fertilizing capacity.
e. allows sperm to mature and acquire fertilizing capacity.
Which of the following is a progesterone antagonist, thereby binding to the
progesterone receptor and blocking the binding and biological activity of
progesterone?

a. RU486
b. Rogaine
c. Viagra
d. Cortisone
e. DHT
a. RU486
In women, which of the following hormones is found at rather low concentrations in
blood except for a brief but dramatic time approximately midway through the
menstrual cycle?

a. inhibin
b. luteinizing hormone
c. progesterone
d. estrogen
e. testosterone
b. luteinizing hormone
In which of the following individuals would concentrations of LH and FSH in blood
and urine be especially high?

a. A woman in the 3rd trimester of pregnancy
b. women with an active corpus luteum
c. women after menopauses
d. a man receiving injections of testosterone expecting to increase fertility
e. women entering puberty
c. women after menopauses
What are polar bodies?

a. structures that are linked together to form the zona pellucida
b. the site where chromosomes from sperm nuclei unravel after fertilization
c. cells that are formed during meiosis in females
d. small organelles that lie just under the plasma membrane of the mature egg
e. chromatin bodies which form when the testes is chilled
c. cells that are formed during meiosis in females
Which of the following represent a correct match?

a. primary oocyte: the cell that is fertilized by sperm
b. secondary oocyte: the type of “egg” that is ovulated
c .Sertoli cell: a nurse cell that surround oocytes
d, primary oocyte: the female germ cell that is haploid
e. second polar body: a diploid cell that divides into two oogonia
b. secondary oocyte: the type of “egg” that is ovulated
If you are asked how oral contraceptives prevent pregnancy, you would correctly
answer that “ They _______.”

a. prevent ovulation
b. prevent the acrosome reaction
c. cause the corpus luteum to degenerate and stop producing progesterone
d. blocks estrogen and progesterone receptors
d. blocks receptors for FSH
a. prevent ovulation
If gonad were removed or destroyed in a genetically male embryo prior to sexual
differentiation, he would develop the basic sexual phenotype of a:

a. female
b. male
c. politician
d. telemarketer
e. teacher
a. female
During normal fertilization, what event directly prevents more than one sperm from
fertilizing the egg?

a. zona pellucida hardening
b. epididymal reaction
c. acrosome reaction
d. loss of sperm tails
e. spasm of oviduct
a. zona pellucida hardening
Assuming a textbook menstrual cycle, why would fertility NOT be expected if intercourse took place on day 25?

a. The LH surge would not occur for 2 to 3 more days.
b. The ovulated egg would be degenerate and be unfertilizable by this time
c. It would take about 5 more days before ovulation and the sperm would not
survive.
d. The low levels of progesterone at that time would prevent proper sperm
transport.
e. The ovulated egg would still be a primary oocyte at that stage and not
fertilizable.
b. The ovulated egg would be degenerate and be unfertilizable by this time
In males, where would you find receptors for LH?

a. oogonia
b. Sertoli cells
c. Leydig cells
d. spermatids
e. spermatogonia
c. Leydig cells
What is the name of the cell type which is located in the seminiferous tubules and
serves as a nurse cell to immature sperm cells on their way to development into
spermatozoa?

a. parietal cells
b. Leydig cells
c. Sertoli cells
d. interstitial cells
e. leucocytes
c. Sertoli cells
The _________, a network of veins leading from the testes, helps maintain the testes
cooler than the core body temperature.

a. rete testes
b. pampiniform plexus
c. glomerular capillaries
d. rete mirabulae
e. choroid plexus
b. pampiniform plexus
Oxytocin from the ________ will cause _______

a. ovary; secretion of milk
b. posterior pituitary; contraction of myoepithelial cells around alveoli
c. anterior pituitary: increased production of LH
d. posterior pituitary: increased production of FSH
e. hypothalamus: relaxation of the uterus
b. posterior pituitary; contraction of myoepithelial cells around alveoli
Negative and positive feedback mechanisms are employed in

a. ovulation
b. establishing the secretary phase of the menstrual cycle.
c. establishing the dominant follicle
d. GnRH secretion
e. developing the proliferative phase of the uterus.
c. establishing the dominant follicle
LH acts directly on the granulosa cells to produce

a. testosterone
b. androgens
c. estrogen
d. HCG
e. FSH
c. estrogen
The acrosome is important in fertilization because it allows the sperm to:

a. avoid fertilizing other sperm.
b. survive for many weeks in the uterus.
c. be motile.
d. avoid being phagocytosed.
e. digest a path through the zona pellucida.
e. digest a path through the zona pellucida.
BPH refers to:

a. Blood placental hormones
b. Brain penis hypothesis
c. Benign prostatic hyperplasis
d. Benign prostatic hemorrhage
c. Benign prostatic hyperplasis
Prostatic cancer may sometimes be treated with

a. oxytocin
b. FSH
c. LH
d. 5 α reductase
e. aromatase
d. 5 α reductase
Drugs such as Viagra use to prolong erections are:

a. vascular dilators
b. prolonging the action of nitric oxide
c. vascular constrictors
d. venous constrictors
e. increasing cardiac output
b. prolonging the action of nitric oxide
Secondary spermatocytes would be found in

a. basal layer of seminiferous tubule
b. lumen of seminiferous tubule
c. adluminal layer of seminiferous tubule
d. in the epididymis
e. in the vas deferens
c. adluminal layer of seminiferous tubule
In a 25-year old woman with a 28 day cycle, the levels of estrogen and progesterone
would be lowest on days

a. 1-6 days
b. 7-13 days
c. 14-16 days
d. 17-21 days
e. 21-28 days
a. 1-6 days
Testosterone levels are maintained at high levels in the seminiferous tubules because
of the

a. FSH
b. LH
c. inhibin
d. androgen binding protein
d. androgen binding protein
The ________ lies next to the surface of the mature ovum.

a. cumulous oophorus
b. granulosa cells
c. theca cells
d. zona pellucida
e. inner cell mass
d. zona pellucida
The ovum is in the oviduct

a. less than one hour
b. 5-10 hours
c. 10-24 hours
d. 24-28 hours
e. more than 36 hours
e. more than 36 hours
When a baby suckles on a mother’s breast, dopamine secretion ______ and oxytocin
is released from the _______

a. increases; anterior pituitary
b. increases; posterior pituitary
c. increases; posterior pituitary
d. decreases; posterior pituitary
e. decreases; hypothalamus
d. decreases; posterior pituitary