Nokea
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.
You may also like to solve these questions
A patient comes in having had repeated colds and infections. Problems in his ear are shown to be due to accumulation of fluid in the middle ear. This is due to a blockage of the:
- A. Saccule
- B. Utricle
- C. External ear
- D. Eustachian tube
Correct Answer: D
Rationale: The correct answer is D: Eustachian tube. The Eustachian tube connects the middle ear to the back of the nose and throat, helping to equalize air pressure and drain fluid from the middle ear. Blockage of the Eustachian tube can lead to fluid accumulation in the middle ear, causing ear problems. The other choices, A: Saccule and B: Utricle, are structures in the inner ear related to balance and hearing, not fluid drainage. Choice C: External ear, refers to the outer ear structures and is not involved in middle ear fluid accumulation.
Which of the following is/are an example(s) of asexual reproduction?
- A. Fission.
- B. Fragmentation.
- C. Budding.
- D. All of the abov
Correct Answer: D
Rationale: The correct answer is D: All of the above. Asexual reproduction involves the production of offspring from a single parent without the involvement of gametes or fertilization.
- Fission: Organism splits into two or more parts, each regenerating into a new individual.
- Fragmentation: Parent organism breaks into fragments, with each fragment developing into a new individual.
- Budding: New individuals develop as outgrowths or buds from the parent organism.
All these processes result in genetically identical offspring, making them examples of asexual reproduction.
With respect to Sertoli cells which of the following statements is incorrect
- A. Nourish developing sperm
- B. receive stimulation by testosterone
- C. phagocytose defective sperm
- D. secrete the hormone inhibin which inhibits luteinizing hormone secretion
Correct Answer: D
Rationale: The correct answer is D because Sertoli cells do secrete inhibin, but it does not inhibit luteinizing hormone secretion. Inhibin actually inhibits follicle-stimulating hormone (FSH) secretion. Sertoli cells support spermatogenesis by nourishing developing sperm (A), they are stimulated by testosterone (B), and they also phagocytose defective sperm (C). Therefore, option D is incorrect as it misrepresents the role of inhibin in the endocrine regulation of the male reproductive system.
How many autosomes does a human primary spermatocyte have?
- A. 34
- B. 44
- C. 54
- D. 33
Correct Answer: B
Rationale: The correct answer is B (44 autosomes) because a human primary spermatocyte is a diploid cell containing a total of 44 autosomes. This is because humans have 22 pairs of autosomes in their somatic cells. During meiosis I, the primary spermatocyte undergoes replication and recombination, resulting in 22 pairs of autosomes (44 autosomes) that will be divided into two haploid secondary spermatocytes. Choices A, C, and D are incorrect because they do not reflect the correct number of autosomes present in a human primary spermatocyte.
Menarche is the
- A. first menses
- B. permanent cessation of menses
- C. first sign of sperm production
- D. time of first ovulation
Correct Answer: A
Rationale: The correct answer is A: first menses. Menarche refers to the onset of a girl's first menstrual period, signifying the beginning of her reproductive years. This event marks the maturation of the reproductive system and the ability to conceive. The other choices are incorrect because menarche does not refer to the permanent cessation of menses (choice B), the first sign of sperm production (choice C), or the time of first ovulation (choice D). Menarche specifically pertains to the first menstrual cycle in females, indicating the initiation of their menstrual and reproductive functions.