Nokea
Human egg cells are most similar to human sperm cells in their
- A. degree of motility
- B. amount of stored food
- C. chromosome number
- D. shape and size
Correct Answer: C
Rationale: The correct answer is C: chromosome number. Human egg cells and sperm cells both have 23 chromosomes, which is half the total number of chromosomes in a human cell (46). This is crucial for maintaining the correct chromosome number in offspring. Choices A, B, and D are incorrect because:
A: Human egg cells are not motile, while sperm cells are highly motile.
B: Egg cells contain a larger amount of stored food (cytoplasmic material) compared to sperm cells.
D: Egg cells are larger and rounder in shape, while sperm cells are smaller and more streamlined.
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Sperm maturation occurs in the
- A. seminiferous tubules
- B. epididymis
- C. vas deferens
- D. urethra
Correct Answer: B
Rationale: The correct answer is B: epididymis. Sperm maturation occurs in the epididymis, a coiled tube located on the posterior surface of the testes. Here, sperm undergo the process of capacitation, gaining the ability to fertilize an egg. The seminiferous tubules (choice A) are responsible for sperm production, not maturation. The vas deferens (choice C) is a duct that carries mature sperm from the epididymis to the urethra, and the urethra (choice D) is a passage for both urine and sperm but not the site of sperm maturation.
The condition of a hidden testicle is of which type of tissue?
- A. skeletal muscle
- B. phimosis.
- C. epithelial tissue
- D. orchiditis.
Correct Answer: D
Rationale: The correct answer is D: orchiditis. Orchiditis refers to inflammation of the testicle, which is a type of tissue found in the male reproductive system. This condition specifically affects the testicular tissue, leading to pain, swelling, and possible complications. Skeletal muscle (choice A) is not related to the testicle, phimosis (choice B) is a condition of the foreskin, and epithelial tissue (choice C) primarily covers the surface of organs, not the testicle itself. Therefore, orchiditis is the most relevant choice for a condition affecting testicular tissue.
Structurally, the testicle is made up of:
- A. intratesticular spermatic ducts;
- B. lobules, delineated by connective septa;
- C. the cortical zone, in the center;
- D. the medullar zone, at the periphery;
Correct Answer: B
Rationale: The correct answer is B: lobules, delineated by connective septa. The testicle is structurally organized into lobules separated by connective tissue septa. Each lobule contains seminiferous tubules where sperm production occurs. This organization allows for efficient production and transport of sperm.
Incorrect choices:
A: Intratesticular spermatic ducts - Incorrect, as the testicle contains seminiferous tubules, not spermatic ducts.
C: The cortical zone, in the center - Incorrect, as the testicle structure does not have a defined cortical zone.
D: The medullar zone, at the periphery - Incorrect, as the medullary zone is not at the periphery but rather towards the center of the testicle.
Before intercourse, a woman irrigates her vagina with a solution that lowers the pH of the vaginal fluid to 4.5. What will be the effect on sperm cells in the vagina?
- A. Metabolic rate will increase
- B. Rate of movement will decrease
- C. Formation of prostaglandin E2 will increase
- D. Rate of oxygen consumption will increase
Correct Answer: B
Rationale: The correct answer is B: Rate of movement will decrease. Sperm cells require a slightly alkaline environment to maintain their motility. Lowering the pH to 4.5 will create an acidic environment, causing decreased sperm motility. Choice A is incorrect as lowering pH doesn't affect metabolic rate. Choice C is incorrect because prostaglandin E2 formation is not directly related to pH changes. Choice D is incorrect as oxygen consumption rate of sperm cells is not affected by vaginal pH.
Where does implantation of the blastocyst occur?
- A. uterine tubes
- B. endometrium
- C. cervix
- D. ovary
Correct Answer: B
Rationale: The correct answer is B: endometrium. After fertilization, the blastocyst travels through the uterine tubes and implants into the endometrium for further development. The endometrium is the inner lining of the uterus where implantation occurs to establish pregnancy. The uterine tubes (choice A) are the site of fertilization, but not implantation. The cervix (choice C) is the lower part of the uterus that connects to the vagina and does not play a role in implantation. The ovary (choice D) is where the egg is released during ovulation and not the site of implantation.