Pace Quiz 1 Part 2

Explanation
The cancer cells from this lesion would directly metastasize to the deep inguinal nodes. This is because the deep inguinal nodes are the primary drainage pathway for lymphatic fluid from the lower extremities, including the area where the lesion is located. Squamous cell carcinoma is known to spread via lymphatic channels, and the deep inguinal nodes are the first lymph nodes along this pathway.

Explanation
The cell type at the arrow contains 46 chromosomes and a chromatid number of 2N. This means that the cell is diploid, with two sets of chromosomes, and each chromosome is replicated and consists of two chromatids.

Explanation
The correct answer is the Bulbourethral gland. This gland is located in the male reproductive tract and is composed of tubuloalveolar glands. It secretes a clear mucous-like secretion that helps to coat the urethra in preparation for ejaculation.

Explanation
The BCR-ABL gene is involved in causing cell growth in leukemias. This gene is a fusion gene that results from a translocation between chromosomes 9 and 22. The fusion protein produced by this gene has uncontrolled tyrosine kinase activity, which leads to the abnormal growth and division of white blood cells, characteristic of leukemias. This gene is particularly associated with chronic myeloid leukemia (CML), where it plays a crucial role in the pathogenesis of the disease. Inhibitors targeting the BCR-ABL protein, such as imatinib, have revolutionized the treatment of CML.

Explanation
The most likely explanation is that there was a laboratory error in the testing of II-3. This is supported by the fact that II-3 initially tested negative for the mutation seen in her brother, but the subsequent pregnancy test showed a deletion of exon 45-48 consistent with being affected with DMD. The inconsistency between the two test results suggests a possible error in the laboratory testing process for II-3.

Explanation
FSH is the best answer. but...
Explanation: Testosterone and FSH are the hormones that predominantly regulate spermatogenesis. Intra-testicular levels of testosterone are approximately 100 fold higher than DHT. First, recognize that testosterone (produced in the Leydig cells) binds with the androgen receptor (AR) on the Sertoli cells – and therefore directly regulates Sertoli cell function. Recognize that testosterone is acting DIRECTLY on the AR in the Sertoli cells, and therefore only a small portion of this intra-testicular testosterone is converted to DHT. FSH also binds to the FSH receptor on the Sertoli cell, and the cumulative actions of testosterone and FSH collectively regulate spermatogenesis. Thus, although DHT is produced in the Sertoli cells, it is the actions of testosterone (acting through the AR on the Sertoli cell) that is the primary androgen regulating spermatogenesis.
I decided to accept DHT as an answer for a few reasons:
1. Testosterone is converted via 5 alpha reductase (5ARD) to DHT in the Sertoli cells – and this is a highly efficient process – BUT- the majority of testosterone is bound to the AR. However, this DHT then binds to the AR in Sertoli cells or, the DHT is secreted into the tubular fluids. In essence, we do not know the exact role of DHT in the tubular fluids, and the administration of DHT inhibitors DO NOT (in most studies) reduce sperm count – but instead, those DHT inhibitors reduce sperm motility. Thus – in this particular question/answer – because sperm motility was not impaired, DHT would not be a correct answer.
2. Additionally, the man (in this particular question) may have a deficiency in 5ARD which would reduce intra-testicular production of DHT. Although the exact role of DHT within the tubular fluids is not known (as mentioned above), there are a few reports and some evidence that indicate individuals with 5ARD deficiency present with decreased sperm count, with a higher percentage of abnormal sperm. As you might expect – the lack of DHT also renders the sperm immotile in 5ARD deficient individuals.

Collectively though, please recognize that testosterone and FSH are the primary endocrine hormones that regulate spermatogenesis.

Explanation
This woman's menstrual periods can be defined as oligomenorrhea. Oligomenorrhea refers to infrequent menstrual cycles, with intervals longer than 35 days. In this case, the woman's cycles are occurring every 7-10 weeks, which is significantly longer than the normal 28-day cycle. The fact that her plasma levels of estradiol and progesterone are normal for the luteal phase of the menstrual cycle suggests that ovulation is occurring, but at irregular intervals.

Explanation
During the late proliferative phase of the menstrual cycle, estrogen concentration increases markedly. This increase in estrogen stimulates the release of the gonadotropins, which are hormones responsible for the development and maturation of the ovarian follicles. This phase occurs after the menses phase, when the uterine lining is shed, and before the mid-secretory phase, when the uterine lining thickens in preparation for potential implantation.

Explanation
Finasteride is the most likely drug prescribed in this case. It is a medication commonly used to treat benign prostatic hyperplasia (BPH), which is characterized by an enlarged prostate gland. Finasteride works by inhibiting the conversion of testosterone to dihydrotestosterone (DHT), a hormone that contributes to prostate enlargement. By reducing DHT levels, finasteride can help prevent further enlargement of the prostate and may even help reduce its size. This drug is frequently prescribed for patients with BPH to alleviate urinary symptoms such as frequent urination, difficulty starting urination, and dribbling after urination.

Explanation
The most likely reason for adding the low-dose oral contraceptive (OC) is to prevent bone loss. Leuprolide, a gonadotropin-releasing hormone (GnRH) agonist, is known to cause estrogen deficiency, which can lead to bone loss and osteoporosis. By prescribing a low-dose OC, the physician can provide exogenous estrogen, which helps maintain bone density and prevent bone loss. This is especially important for the patient who wishes to have children in the future and wants to minimize the impact of endometriosis treatment on her fertility and overall health.

Explanation
The structures indicated by the pointer in the photomicrograph of the ovary produce androstenedione.

Explanation
The structures indicated by the pointer in the photomicrograph can be derived from primordial, primary, secondary, and Graafian follicles.

Explanation
The correct answer is "Influenced mainly by progesterone". During the luteal phase of the menstrual cycle, the endometrium undergoes changes in response to increased progesterone levels. Progesterone stimulates the development of the secretory glands in the endometrium, preparing it for potential implantation of a fertilized egg. If fertilization does not occur, progesterone levels decrease, leading to shedding of the endometrium during menstruation.

Explanation
Pay close attention to the TWO barr bodies. while the XXY can give excessive height, there would ABSOLUTELY not be TWO barr bodies.