Nokea
Circular movement around an axis is known as ___________________.
- A. Dorsiflexion
- B. Rotation
- C. Extension
- D. Pronation
Correct Answer: B
Rationale: The correct answer is B: Rotation. Circular movement around an axis is described as rotation. This movement involves turning or spinning around a fixed point. Dorsiflexion (A) is the movement of bringing the top of the foot towards the shin. Extension (C) refers to straightening or increasing the angle of a joint. Pronation (D) is the inward rotation of the forearm or foot. Rotation (B) specifically signifies movement around an axis, making it the most appropriate choice for circular movement.
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A 20-year-old woman is not having menstrual cycles. Her plasma progesterone concentration is found to be minimal. What is the explanation for the low level of progesterone?
- A. LH secretion rate is elevated
- B. LH secretion rate is suppressed
- C. FSH secretion rate is suppressed
- D. No corpus luteum is present
Correct Answer: D
Rationale: The correct answer is D: No corpus luteum is present. The corpus luteum is responsible for producing progesterone after ovulation. Without a corpus luteum, progesterone levels will be minimal, leading to a lack of menstrual cycles.
A: If LH secretion rate is elevated, it would lead to increased corpus luteum formation and progesterone production.
B: If LH secretion rate is suppressed, there would be insufficient stimulation for corpus luteum formation and progesterone production.
C: FSH is responsible for follicle development, not progesterone production.
Which of the following are all components of sperm?
- A. acrosome, flagellum, nucleus
- B. codpiece, flagellum, midpiece
- C. nucleus, seminal vesicles, mitochondria
- D. DNA, flagellum, efferent ductules
Correct Answer: A
Rationale: The correct answer is A: acrosome, flagellum, nucleus. The acrosome contains enzymes for penetrating the egg. The flagellum is the tail for movement. The nucleus contains genetic material. Choice B is incorrect because a codpiece is a protective garment and not a component of sperm. Choice C is incorrect because seminal vesicles and mitochondria are not components of sperm. Choice D is incorrect because efferent ductules are part of the male reproductive system, not a component of sperm.
The endocrine role of the testicle:
- A. occurs at the level of the interstitial cells;
- B. consists in the secretion of androgenic hormones;
- C. consists in the secretion of testosterone;
- D. determines the maturation of the sex organs;
Correct Answer: C
Rationale: The correct answer is C because the endocrine role of the testicle primarily involves the secretion of testosterone. Testosterone is the main androgenic hormone produced by the testicles, which plays a crucial role in various physiological functions such as the development of male reproductive organs, sperm production, and secondary sexual characteristics.
Choice A is incorrect because while interstitial cells (Leydig cells) are involved in the production of testosterone, the endocrine role of the testicle is not limited to these cells alone.
Choice B is incorrect as it is too general. While androgenic hormones are indeed secreted by the testicles, testosterone specifically is the main androgenic hormone produced by them.
Choice D is incorrect as the maturation of sex organs is primarily regulated by the action of testosterone but is not the sole endocrine role of the testicle.
The accessory glands of the male reproductive system are:
- A. corpus spongiosum;
- B. corpus cavernosum;
- C. penis;
- D. seminal vesicles;
Correct Answer: D
Rationale: The correct answer is D: seminal vesicles. Seminal vesicles are accessory glands that produce a significant portion of the fluid that makes up semen. They contribute nutrients and substances that support sperm viability and motility. Choices A, B, and C are incorrect as they are structures of the penis involved in erection and urination, not accessory glands of the male reproductive system.
The sperm cells:
- A. become mobile in the seminal fluid;
- B. are microscopic cells;
- C. are stored in the crotum;
- D. are of three different kinds;
Correct Answer: A
Rationale: Step-by-step rationale for choice A being correct:
1. Sperm cells need to be mobile to reach the egg for fertilization.
2. Seminal fluid provides the environment for sperm motility.
3. Sperm cells acquire motility in the seminal fluid due to specific nutrients and ions present.
Summary of why other choices are incorrect:
- Choice B: Being microscopic is a general characteristic of sperm cells but not specific to their mobility.
- Choice C: Sperm cells are stored in the epididymis, not the "crotum."
- Choice D: Sperm cells are all of the same kind, not three different kinds.