Which of the following statements is incorrect?
- A. both luteinising hormone and follicle stimulating hormone are secreted by the hypothalamus
- B. testosterone stimulates sertoli cells
- C. luteinising hormone stimulates Leydig cells to make testosterone
- D. sertoli cells secrete inhibin
Correct Answer: A
Rationale: The correct answer is A because luteinising hormone (LH) and follicle stimulating hormone (FSH) are not secreted by the hypothalamus, but by the anterior pituitary gland. LH stimulates Leydig cells to produce testosterone, not the hypothalamus. Testosterone stimulates sertoli cells, not the other way around. Inhibin is indeed secreted by sertoli cells, but it does not relate to the incorrect statement regarding the origin of LH and FSH.
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Infertility could develop when the sperm cells display _____.
- A. a count of 120 million per ml semen
- B. increased acrosomal activity
- C. normal morphology
- D. a count of less than 20 million per ml semen
Correct Answer: D
Rationale: The correct answer is D because a low sperm count (less than 20 million per ml semen) can lead to infertility as it decreases the chances of successful fertilization. A high sperm count (choice A) is actually beneficial for fertility. Increased acrosomal activity (choice B) can enhance fertilization potential. Normal morphology (choice C) refers to the shape and size of sperm, which is important for fertility but not the primary factor in infertility due to low sperm count. Overall, a low sperm count is the most significant factor in infertility.
The tiny female sex cell that unites with male sperm to form a zygote or fertilized egg.
- A. Ovary
- B. Ovum
- C. Gonad
- D. Gamets
Correct Answer: B
Rationale: The correct answer is B: Ovum. The ovum is the mature female sex cell that unites with a male sperm during fertilization to form a zygote. Ovary (A) is the organ that produces eggs but is not the actual female sex cell. Gonad (C) is a general term for reproductive organs, not the specific female sex cell. Gametes (D) refer to both male and female sex cells, so it is a broad term and not the specific female sex cell. The ovum is the only choice that accurately represents the tiny female sex cell involved in fertilization.
Sexual feelings are normal and necessary
- A. for reproduction to occur
- B. for the heart and lungs to function properly
- C. for an ovum to be released from a female’s ovary each month
- D. for teens to become adults
Correct Answer: A
Rationale: The correct answer is A because sexual feelings are indeed necessary for reproduction to occur. Sexual arousal and desire play a vital role in initiating the process of conception and ensuring the continuation of the human species. Without sexual feelings, procreation would not be possible.
Explanation for why the other choices are incorrect:
B: Sexual feelings are not necessary for the heart and lungs to function properly. These bodily functions are regulated by the autonomic nervous system, not by sexual arousal.
C: While sexual feelings can influence the release of an ovum during ovulation, they are not the sole factor. Ovulation can occur without sexual arousal.
D: Sexual feelings are not a requirement for teenagers to become adults. Puberty and the physical and emotional changes that come with it mark the transition from adolescence to adulthood, not sexual feelings.
The roles of the testicle are:
- A. endocrine gland (to produce sperm cells);
- B. exocrine gland (to secrete androgenic hormones);
- C. spermatogenesis;
- D. generation of semen;
Correct Answer: C
Rationale: Rationale for correct answer (C): The main function of the testicles is spermatogenesis, which is the process of producing sperm cells. This is a crucial role in male reproductive system. Spermatogenesis occurs in the seminiferous tubules of the testes. Other functions like producing androgenic hormones (choice B) are mainly carried out by the Leydig cells in the testes, not the testicles themselves. While the testicles do play a role in semen production (choice D), this is not their primary function. Therefore, the correct answer is C as it directly relates to the main purpose of the testicles in the male reproductive system.
How long are the typical ovarian and uterine (menstrual) cycles in a female?
- A. 7 days
- B. 14 days
- C. 28 days
- D. 40 days
Correct Answer: C
Rationale: The correct answer is C (28 days) because the typical ovarian and uterine (menstrual) cycles in a female are both around this duration. The menstrual cycle is typically 28 days, with ovulation occurring around day 14. This cycle is regulated by hormonal fluctuations and prepares the uterus for potential pregnancy. Choices A, B, and D are incorrect because a 7-day cycle is too short for a full menstrual cycle, a 14-day cycle is typically the duration of ovulation, and a 40-day cycle is longer than the average menstrual cycle length.