Nokea
In male embryos, which hormone is responsible for the development of the urethra, prostate, and external genitals?
- A. dihydrotestosterone (DHT)
- B. FSH
- C. Progesterone
- D. Estrogen
Correct Answer: A
Rationale: The correct answer is A: dihydrotestosterone (DHT). DHT is a potent form of testosterone responsible for male sexual development, including the formation of the urethra, prostate, and external genitals. It binds to androgen receptors in target tissues, promoting their growth and differentiation. FSH (Choice B) is follicle-stimulating hormone, which primarily regulates sperm production in males. Progesterone (Choice C) is a female sex hormone involved in the menstrual cycle and pregnancy. Estrogen (Choice D) is a female sex hormone responsible for female reproductive development. Thus, A is the correct answer as it specifically pertains to male sexual differentiation.
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Within which structure in the human body does specialization of parts of the developing baby take place?
- A. ovary
- B. uterus
- C. testis
- D. pancreas
Correct Answer: B
Rationale: The correct answer is B: uterus. Specialization of parts of the developing baby takes place in the uterus during pregnancy. The uterus is where the fertilized egg implants and the embryo develops into a specialized structure known as a fetus. The other choices (A: ovary, C: testis, D: pancreas) do not play a direct role in the development of the baby during pregnancy. The ovary is involved in producing eggs, the testis produces sperm, and the pancreas is responsible for producing digestive enzymes and hormones, but they are not directly involved in the specialization of parts of the developing baby.
The following take part in the fecundation process:
- A. a single ovule;
- B. a single fecundated spermatozoon;
- C. one ovule with two nuclei, which means the pregnancy is monovitelline twin;
- D. two ovules, which means the pregnancy is bivitelline twin;
Correct Answer: C
Rationale: The correct answer is C, one ovule with two nuclei, which means the pregnancy is monovitelline twin. This is correct because during fertilization, a single sperm fertilizes an ovum, resulting in the formation of a zygote with two nuclei. Monovitelline twins originate from the splitting of a single fertilized egg, leading to two embryos with shared genetic material. The other choices, A and B, are incorrect as they do not accurately represent the process of fecundation. Choice A refers to a single ovule before fertilization, and choice B refers to a single spermatozoon, which is involved in fertilization but does not lead to the formation of twins. Choice D is also incorrect as it describes bivitelline twins, which result from the fertilization of two separate eggs by two different sperm, leading to genetically distinct individuals.
Which structure will actually become the fetus?
- A. morula
- B. blastocyst
- C. inner cell mass
- D. zygote
Correct Answer: C
Rationale: The correct answer is C: inner cell mass. After fertilization, the zygote undergoes several cell divisions to form a hollow ball of cells called a blastocyst. Within the blastocyst, the inner cell mass contains cells that will develop into the fetus. The morula is an earlier stage consisting of a solid ball of cells. The zygote is the initial cell formed from the fusion of egg and sperm, but it does not directly become the fetus. Therefore, the inner cell mass is the structure that will actually develop into the fetus, making it the correct answer.
When a nurse is educating a group of women about the risks of breast cancer, she includes which of the following common risk factor?
- A. Older than 30 years of age
- B. Family history of breast cancer
- C. African-American heritage
- D. Breast tenderness, without any sensation
Correct Answer: B
Rationale: Family history is a well-established risk factor for breast cancer.
With respect to the effects of testosterone in the male which statement is incorrect?
- A. testosterone inhibits the secretion of luteinising hormone
- B. testosterone stimulates the secretion of inhibin from leydig cells
- C. testosterone induces and maintains male sexual functions
- D. testosterone stimulates protein anabolism and bone growth.
Correct Answer: B
Rationale: The correct answer is B because inhibin is primarily secreted by Sertoli cells in the testes, not Leydig cells. Testosterone actually stimulates the secretion of inhibin from Sertoli cells. In contrast, Leydig cells produce testosterone in response to luteinising hormone (Choice A). Testosterone does play a key role in inducing and maintaining male sexual functions (Choice C) and also stimulates protein anabolism and bone growth (Choice D). Thus, Choice B is incorrect as Leydig cells do not secrete inhibin.