Block 7 Repro Pace Style W Xpl

Testosterone is converted into dihydrotestosterone (DHT) by 5-alpha reductase. DHT is crucial for proper male development. Failure to produce enough testosterone and/or DHT may result in male pseudohermaphrodism (male genotype with feminized phenotype).

Testosterone is involved in all of the processes mentioned. It plays a crucial role in the initiation of spermatogenesis, inhibits the release of GnRH (gonadotropin-releasing hormone) which in turn inhibits the production of LH (luteinizing hormone), it also contributes to bone growth, and stimulates the secretion of erythropoietin, a hormone that promotes the production of red blood cells. Therefore, all of the given options are related to testosterone.

Only D would completely prevent pregnancy from happening. All other answers would likely result in fertility issues but would still allow pregnancy to occur.

Sertoli cells make inhibin, which inhibits FSH. Leydig cells make testosterone which inhibits LH. Testosterone also inhibits GnRH, which is produced in the hypothalamus to promote production of the three glycoproteins LH, FSH, and TSH in the anterior pituitary

Peyronie's disease is a disorder of inappropriate fibrosis of the penis. This typically results in an upward bend of the erect penis, and may result in painful erections. Hypospadius also may cause a bend in the penis, but will typically cause a downward bend. Moreover, hypospadius would likely have been addressed soon after birth. None of the other conditions are likely to result in a bent shaft.

Only oogenesis produces polar bodies. After completion of meiosis I, one polar body is produced. After meiosis II, either two or three polar bodies have been produced, depending on whether the first polar body replicated

The proposed mechanism for BPH is that testosterone is converted to DHT by 5-alpha reductase in the stromal cells of the prostate. DHT then binds to androgen receptors in both stromal cells and epithelial cells, resulting in production of growth factors which produce hyperplasia. Other factors are likely important, since experiments with 5-alpha reductase inhibitors did not benefit all patients who took it. (Robbins 7th Ed, pg 1049). 5-alpha reductase is a better target than testosterone since DHT is 10x more potent at activating androgen receptors. Other appropriate targets for therapy may include the androgen receptors and growth factor receptors.

The correct answer is anterior to rectal wall, 2.5 cm. During a digital rectal exam, the prostate gland can be felt by inserting a finger into the rectum. The normal position of the prostate is in front of the rectal wall, which is why it is described as "anterior." The size of a normal prostate, when measured from side to side, is typically around 2.5 cm.

The correct path out of a testis is seminiferous tubule, rete testis, efferent ductules, epididymis, vas deferens. The only answer that follows this path is E.

Squamous cell carcinoma of the penis accounts for less than 1% of male cancer in the US. However, it is up to 20x more common in many other parts of the world. Risk factors include an uncircumcised penis, poor hygiene, HPV-16 and HPV-18, and cigarette smoking. Inguinal and iliac lymph nodes are highly susceptible to metastasis. Therefore, the next best step is to biopsy these lymph nodes.

Dr. Nichols said that a good guess can be made by the 9 week. However, 8 weeks is clearly too early, so A is incorrect. 12 weeks is the number given in his PowerPoint.

The optimal temperature is 5.6 degrees below body temperature, according to Dr. Beisel's lecture. 98.6 - 5.6 = 93.0

Hypospadius are related to deficiencies in testosterone. Epispadias occur earlier in development and are unrelated to hypospadius. Epispadias are associated with extrophy of the bladder, and hypospadius is not.

The features of benign hypertrophy include symmetrical enlargement, protusion into the rectal lumen, smooth, no nodules, as well as elastic or rubbery consistency. Prostate cancer is largely the opposite of this, including features such as hard consistency, asymmetry, and nodules. Both may have an unidentifiable median sulcus.

The testicles typically descent around the 7th or 8th month. It would not be uncommon to see undescended testes (aka cryptorchidism) at this stage. However, microcephaly and foot deformity should alert you to a more severe problem. Descent of the testes occurs in two distinct stages. First, the trans-abdominal stage depends on mullerian inhibiting substance, produced by Sertoli cells. The second stage, or trans-inguinal stage, is controlled by androgens. However, according to 7th Edition Robbins pg. 1038, cryptorchidism is only "rarely associated with hormonal disorders". Chromosomal disorders are more likely. Common features of trisomy 13 include microcephaly, cleft lip, heart defects, and rocker-bottom feet.

There has been clear evidence to suggest that circumcision reduces the likelihood of HIV and UTIs, as well as squamous cell carcinoma. No such evidence exists for BPH.

Answer: B,D HPV 6 and 11 are the most common cause of condyloma acuminatum, or benign genital warts, accounting for ~90% of all cases. Answer F,G HPV 16 and 18 are associated with carcinoma of the penis. The role of HPV in malignancy is unclear.

Precocious sexual development can be the result of 21-beta-hydroxylase deficiency. This deficiency will reduce the output of both mineralocorticoids (from the zona glomerulosa) and glucocorticoids (zona fasciculata). The anterior pituitary responds by increasing ACTH. As a result, there is overproduction of androgens (zona reticularis), which can lead to early sexual development. The increase in androgens will be broken down into excretory metabolites such as 17-ketosteroids, leading to increased urinary levels. Hyperglycemia is more likely to be seen in cortisol excess, and anosmia is associated with eunuchoidism (failure to enter puberty).

Both deficiencies result in a decrease in cortisol levels which results in an increase in ACTH. 21-beta-hydroxylase causes adrenogenital syndrome, where only androgens are increased. 17-alpha-hydroxylase deficiency results in decrease in all except mineralocorticoids. Here's a visual:
----------------------------21-β-hydroxylase deficiency .............17-α-hydroxylase deficiency

zona granulosa - aldosterone + aldosterone

zona fasciculata - cortisol - cortisol

zona reticularis + androgens - androgens

Eunuchoidism is the failure of puberty to begin and proceed. There should be no hormonal increase that would result in gynecomastia. A less obvious feature is that these individuals tend to have long legs and therefore a sitting height less than half of their standing height. Anosmia is commonly seen in eunuchoids because there is often a problem in the pituitary which may affect the nearby olfactory system.