Question 1

Which structure is responsible for maintaining the testes at a temperature lower than core body temperature, and what is the physiological significance of this temperature difference?

Accepted Answer

The scrotum; it keeps the testes at 3{C} below core body temperature, which is essential for proper spermatogenesis.

Question 2

During spermatogenesis, which cell type undergoes meiosis I, and what is the resulting cell type?

Accepted Answer

Primary spermatocytes undergo meiosis I to produce secondary spermatocytes.

Question 3

Which hormone is primarily responsible for stimulating the Leydig (interstitial) cells to produce testosterone, and what is the feedback mechanism involved?

Accepted Answer

LH; negative feedback by testosterone inhibiting GnRH and LH release.

Question 4

A patient presents with infertility due to immune destruction of sperm. Which cell type is most likely dysfunctional, and what is its primary role?

Accepted Answer

Sertoli cells; they form the blood-testis barrier to protect developing sperm from immune attack.

Question 5

During the ovarian cycle, what triggers the LH surge, and what is the immediate consequence of this surge?

Accepted Answer

High estrogen levels; triggers ovulation.

Question 6

If fertilization does not occur, what happens to the corpus luteum and how does this affect the uterine lining?

Accepted Answer

The corpus luteum degenerates into the corpus albicans, progesterone levels drop, and the stratum functionalis is shed during menstruation.

Question 7

Which event marks the completion of meiosis II in oogenesis, and what is the resulting cell type?

Accepted Answer

Fertilization; produces a diploid zygote ($$2n) $$and a second polar body.

Question 8

Which mechanism prevents polyspermy during fertilization, and what is the sequence of events?

Accepted Answer

Fast block: membrane depolarization; slow block: calcium influx causes cortical granules to harden the zona pellucida.

Question 9

A blastocyst consists of two main cell populations. Which cells form the placenta, and which become the embryo?

Accepted Answer

Trophoblast forms the placenta; inner cell mass forms the embryo.

Question 10

Which extraembryonic membrane is directly responsible for forming the structural base of the umbilical cord and linking to the urinary bladder?

Accepted Answer

Allantois

Question 11

During gastrulation, which germ layer gives rise to the nervous system, and what is the process called?

Accepted Answer

Ectoderm; neurulation

Question 12

A newborn is diagnosed with a patent ductus arteriosus. Which fetal circulatory shunt is involved, and what is its normal postnatal fate?

Accepted Answer

Ductus arteriosus; normally constricts and becomes ligamentum arteriosum.

Question 13

Which hormone is released in response to infant suckling and is responsible for the milk let-down reflex?

Accepted Answer

Oxytocin

Question 14

Colostrum differs from mature breast milk in which of the following ways?

Accepted Answer

It is low in fat, high in protein, and rich in IgA antibodies for passive immunity.

Question 15

A man with genotype $$XY$$ inherits an X-linked recessive allele for red-green color blindness. What is his phenotype?

Accepted Answer

He is affected and will express red-green color blindness.

Question 16

Which inheritance pattern is characterized by heterozygotes displaying a blended phenotype, and what is an example?

Accepted Answer

Incomplete dominance; familial hypercholesterolemia

Question 17

In autosomal recessive inheritance, what is the probability that two heterozygous parents ($$Aa 	imes Aa) $$will have a child affected by the disease?

Accepted Answer

25%

Question 18

A patient with Huntington's disease has genotype $$Aa. $$What is the inheritance pattern, and what is the expected phenotype?

Accepted Answer

Autosomal dominant; affected phenotype

Question 19

Which accessory gland contributes the majority of the volume to semen and what is its main function?

Accepted Answer

Seminal vesicles; produce alkaline fluid with fructose for energy and prostaglandins to reverse uterine contractions.

Question 20

During cleavage, the zygote undergoes rapid mitotic divisions. What is the main outcome of this process?

Accepted Answer

Formation of smaller cells called blastomeres without increasing overall volume.

Integrated Study Guide: The Reproductive System, Development, and Inheritance

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