Nokea
The fecundated spermatozoon contains:
- A. 11 pairs of somatic chromosomes;
- B. 22 somatic chromosomes ;
- C. only the X sex chromosome;
- D. the X or Y sex chromosome
Correct Answer: D
Rationale: The correct answer is D because the fecundated spermatozoon can contain either the X or Y sex chromosome, determining the genetic sex of the offspring. Spermatozoa are haploid cells, meaning they contain only one set of chromosomes. During fertilization, the spermatozoon fuses with the ovum, which also contains a single set of chromosomes, resulting in a diploid zygote with a complete set of chromosomes. Choices A and B are incorrect as somatic chromosomes refer to the non-reproductive cells in the body, not the chromosomes found in gametes. Choice C is incorrect because the spermatozoon can carry either the X or Y sex chromosome, not exclusively the X chromosome.
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Primary spermatogonium undergo:
- A. two mitotic divisions to become a secondary spermatocyte
- B. mitosis and then meiosis to become a secondary spermatocyte
- C. two meiotic divisions to become a secondary spermatocyte
- D. meiosis and differentiation to become a secondary spermatocyte
Correct Answer: B
Rationale: The correct answer is B. Primary spermatogonium undergo mitosis to replicate and maintain the diploid chromosome number, then meiosis to reduce the chromosome number, resulting in secondary spermatocytes. Choice A is incorrect as it skips meiosis. Choice C is incorrect as it suggests two meiotic divisions from primary spermatogonium, which is not accurate. Choice D is incorrect because it fails to mention the initial step of mitosis before meiosis in the process.
A mature ovarian follicle that is ready to be ejected from an ovary is called a(n) ________.
- A. primary oocyte
- B. vesicular (Graafian) follicle
- C. ovum
- D. corpus luteum
Correct Answer: B
Rationale: The correct answer is B: vesicular (Graafian) follicle. A mature ovarian follicle ready for ovulation is called a vesicular follicle. It is the final stage before ovulation. A: primary oocyte is incorrect as it refers to an immature egg cell. C: ovum is incorrect as it refers to a mature egg cell after fertilization. D: corpus luteum is incorrect as it forms after ovulation and is responsible for producing progesterone, not the mature follicle.
________ vertebrae are the strongest and largest of the vertebral column.
- A. Lumbar
- B. Sacrum
- C. Thoracic
- D. Cervical
Correct Answer: A
Rationale: The correct answer is A: Lumbar vertebrae. The lumbar vertebrae are the largest and strongest of the vertebral column due to their weight-bearing function in supporting the upper body. They have a larger body and thicker structures compared to other vertebrae, providing stability and support. The sacrum, thoracic, and cervical vertebrae are not as large or strong as the lumbar vertebrae, as they have different functions and shapes tailored to their specific roles in the spine.
The scrotum:
- A. is located above the external male genital organ;
- B. shelters the male gonad;
- C. is made up of concentric tunics, a continuation of the ones from the anterior abdominal wall;
- D. is part of the external genital organs;
Correct Answer: B
Rationale: The correct answer is B: shelters the male gonad. The scrotum houses and protects the testes, the male gonads responsible for sperm production. This is crucial for maintaining optimal temperature for spermatogenesis. Choices A, C, and D are incorrect as the scrotum is located below the external male genital organ, has separate tunics from the abdominal wall, and is considered part of the external genital organs.
About the vascularization of the uterus we can state the following:
- A. the arteries branch off the common iliac artery;
- B. the arteries are branches off the abdominal aorta;
- C. the veins open in the inferior vena cava;
- D. the arteries are branches off the internal iliac artery;
Correct Answer: B
Rationale: The correct answer is B because the arteries supplying the uterus arise from the abdominal aorta. The uterine arteries branch off the anterior division of the internal iliac artery, which itself arises from the posterior division of the internal iliac artery. This vascular supply ensures that the uterus receives oxygenated blood rich in nutrients necessary for its proper function.
Choice A is incorrect because the common iliac artery does not directly supply blood to the uterus. Choice C is incorrect because the veins draining the uterus ultimately empty into the internal iliac veins, which then drain into the common iliac veins and not directly into the inferior vena cava. Choice D is incorrect because while the uterine arteries are indeed branches off the internal iliac artery, the internal iliac artery itself arises from the common iliac artery and not directly from the abdominal aorta.