MCAT Biology : Reproductive System

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

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Example Question #1 : Systems Biology And Tissue Types

Follicle-stimulating hormone (FSH) stimulates the growth of a follicle in the ovary, a process that occurs __________.

Possible Answers:

only before the female is born

between puberty and menopause

between birth and puberty

between fertilization and birth

Correct answer:

between puberty and menopause

Explanation:

At puberty, the oocytes arrested at birth in meiosis I resume growth. This most often happens once a month, if fertilization has not occurred, and continues from puberty until menopause. The oocytes arrested at birth complete meiosis I, and are then arrested in meiosis II until fertilization occurs. During ovulation, the follicle ruptures and develops into the corpus luteum. Without fertilization, the endometrium is shed and the cycle continues. Once menopause is reached, this cycle ceases and most often women are no longer fertile.

Example Question #1 : Female Reproductive Physiology

The hormones FSH and LH are involed in oogenesis in women. When LH surges in the ovarian cycle, what event will result?

Possible Answers:

Menstruation

Corpus luteum degradation

None of the above

Endometrium proliferation

Ovulation

Correct answer:

Ovulation

Explanation:

Follicles are stimulated to grow when FSH level rises. The follicles produce estrogen that exerts a positive feedback on LH, whose levele begin to rise. When LH levels peak on the 14th day of the cycle, the follicle ruptures, releasing the egg from the ovary and leaving the corpus luteum behind in the ovary. After ovulation, the corpus luteum secretes both estrogen and progesterone to inhibit GnRH. When GnRH is inhibited, FSH and LH will also be inhibited. 

Example Question #1 : Female Reproductive Physiology

An environmental toxin has been found to directly disrupt normal gamete production in women. What tissue or organ is the toxin likely localizing to?

Possible Answers:

Ovaries

None of these

Oviduct

Endometrium

Uterus

Correct answer:

Ovaries

Explanation:

The most likely localization of the toxin would be to the ovaries, since this is where gamete production begins for females. For males, gametes are produced in the testes. The incorrect answers are all parts of the female reproductive system. The oviduct is where fertilization takes place. The endometrium (the lining of the uterus) is where the embryo will eventually implant.

Example Question #1 : Systems Biology And Tissue Types

Which of the following describes the function of follicle-stimulating hormone in females?

Possible Answers:

Promote growth of immature follicles in ovaries

Increase basal metabolic rate

Promote milk production

Stimulate estrogen secretion from ovaries

Correct answer:

Promote growth of immature follicles in ovaries

Explanation:

Follicle-stimulating hormone stimulates the growth of granulosa cells surrounding the primary oocyte within the ovary, which further promotes maturity of the immature follicle. Prolactin is the hormone that promotes milk production from mammary glands during pregnancy. In females, luteinizing hormone (LH) supports theca cells in the ovaries, which subsequently give rise to precursors to estrogen production. Thyroid hormones regulate metabolism by increasing basal metabolic rate. 

Example Question #1 : Reproductive System

Progesterone is primarily secreted by which of the following structures?

Possible Answers:

Secondary follicle

Ovum

Primary follicle

Spermatozoon

Corpus luteum

Correct answer:

Corpus luteum

Explanation:

The corpus luteum is the remnant structure of the secondary follicle after the egg is released during ovulation. It secretes progesterone following this process. The other structures do not release appreciable amounts of progesterone; the primary follicle differentiates into the secondary follicle, which in turn releases the ovum, or the egg. The spermatozoon is involved with the fertilization of the egg, and does not release any progesterone. 

Example Question #2 : Reproductive System

 

The presence of which of the following hormones can determine if a woman is two weeks pregnant?

Possible Answers:

Human chorionic gonadotropin (hCG)

Progesterone

Estrogen

Oxytocin 

Testosterone

Correct answer:

Human chorionic gonadotropin (hCG)

Explanation:

Human chorionic gonadotropin (hCG) is a hormone produced by a fertilized egg and can be detected about six days after conception; it is only found in pregnant women, and can be used to help detect pregnancy.

The other answers are hormones that are present in both pregnant and nonpregnant women, so they cannot be used to determine pregnancy. 

Example Question #1 : Reproductive System

Passage:

In a fictional universe, a new life form is discovered that appears to have a number of similarities to humans. Since its discovery by humans, it has been studied with x-ray imaging, magnetic resonance imaging (MRI), computed tomography imaging (CT), as well as with blood chemistries and laboratory studies. Based upon such analyses, scientists have found that both structurally and functionally, this fictional species, called Lorempis marengis, is highly similar to humans. It has structures that appear similar to lungs that are active during respiration. It has a structure that is highly active at all times, especially so in different parts during different activities (similar to the human brain). It also appears to have a digestive tract with a mouth, esophagus, stomach, small intestine, large intestine, and anus that is assumed to carry out the same functions at the cellular level as the parts of the human digestive tract. Scientists are now hoping to continue studying the organism at the cellular level to confirm their assumption that the cellular functions are indeed similar to those of human tissues.

If we assume that Lorempis marengis female reproductive anatomy is identical to that of humans, in which of the following organs are eggs most likely to be stored in Lorempis marengis females?

Possible Answers:

Ovaries

Oviducts

Fallopian Tube

Bartholin's Glands

Uterus

Correct answer:

Ovaries

Explanation:

The most likely site of egg (also know as ovum) storage in Lorempis marengis females is the ovaries. This is the correct answer because we are told to assume that Lorempis marengis female reproductive anatomy is identical to that of humans, and in human females, the site of egg storage is the ovaries. 

Females are born with all of the eggs that they will have throughout their lifespan, and they are stored in the ovaries. When females begin menarche, ovulation begins, in which a single egg is released from one of the ovaries every 28-35 days (until menopause) in preparation for fertilization by sperm. The egg is released from the ovary into the fallopian tube, also known as the oviduct, at which time it may be fertilized by sperm. If fertilization successfully occurs, then the fertilized egg, also known as the zygote, travels down the fallopian tube to the uterus, where it may implant and continue to develop, eventually into a fetus. Thus, each of the above answer choices, other than ovaries, is incorrect, as they represent structures within the female reproductive tract that do not store eggs, but rather are sites than an egg may pass through after it is stored and released from the ovary. 

Bartholin's Glands is an incorrect choice, as they are not sites of egg storage, but rather they serve to secrete lubricating mucus to the vagina.

Example Question #1 : Male Reproductive Physiology

What cell type is responsible for testosterone production in human males?

Possible Answers:

Cells of Leydig

Spermatogonia

Sertoli cells

Zona pellucida

Correct answer:

Cells of Leydig

Explanation:

This question requires knowledge of the different cell types in the human male’s reproductive anatomy. The cells of Leydig (also known as the interstitial cells) secrete testosterone and other androgens (male sex hormones), while the Sertoli cells are responsible for nourishing developing sperm. Spermatogonia are sperm cell precursors, and the zona pellucida refers to one of the layers surrounding an ovum.

Example Question #1 : Male Reproductive Physiology

The scrotum is responsible for which of the following in the male repoductive system?

Possible Answers:

Nourishment of sperm

Androgen synthesis

Synthesis of sperm

Lubrication

Temperature regulation

Correct answer:

Temperature regulation

Explanation:

The scrotum is a bag of skin containing the testes. The importance of the scrotum is to regulate temperature because sperm synthesis in the testes must occur at a few degrees below body temperature. The testes are the location of sperm synthesis, androgen synthesis occurs in the interstitial cells, nourishment of the sperm takes place in the seminal vesicles, and lubrication occurs in the bulbourethral glands.

Example Question #1 : Male Reproductive Physiology

Which of the following answer choices correctly describes the path of a mature sperm, during normal male ejaculation?

Possible Answers:

Epididymis → Vas deferens → Ejaculatory duct → Urinary bladder

Vas deferens → Epididymis → Urethra → Penis

Seminiferous tubule → Epididymis → Vas deferens → Ejaculatory duct

Seminal vesicle → Epididymis → Vas deferens → Ejaculatory duct

Correct answer:

Seminiferous tubule → Epididymis → Vas deferens → Ejaculatory duct

Explanation:

This question requires knowledge of the ejaculatory path in human males. The quick mnemonic for memorizing the pathway is SEVEn UP (Seminiferous tubule, Epididymus, Vas deferens, Ejaculatory duct, nothing, Urethra, Penis). Additionally, this alerts us to an important characteristic of the MCAT. Oftentimes, answer choices for pathway questions will neither start at the beginning of the pathway nor end at the absolute end of the pathway. Because of this, be sure to know all steps of a pathway, not just the beginning or end.

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