Question 1

Which of the following best describes the sequence of events during fertilization leading to the formation of a diploid zygote?

Accepted Answer

Sperm undergoes capacitation, acrosome reaction digests zona pellucida, cortical reaction blocks polyspermy, secondary oocyte completes meiosis II, pronuclei fuse

Question 2

A newborn fails to close the ductus arteriosus after birth. Which of the following is the most likely physiological consequence?

Accepted Answer

Oxygenated and deoxygenated blood will mix between the aorta and pulmonary artery, potentially leading to hypoxemia

Question 3

During which stage of development does gastrulation occur, and what is its primary significance?

Accepted Answer

Embryonic stage; it establishes the three primary germ layers

Question 4

Which hormone is primarily responsible for maintaining the corpus luteum and preventing menstruation during early pregnancy?

Accepted Answer

Human chorionic gonadotropin (hCG)

Question 5

A mutation prevents the formation of surfactant in a newborn. Which immediate adaptation will be most severely affected?

Accepted Answer

The ability to inflate the lungs for the first breath

Question 6

Which of the following best explains why the umbilical vein carries oxygenated blood in fetal circulation?

Accepted Answer

It transports blood from the placenta, where gas exchange occurs, directly to the fetus

Question 7

A patient is given a drug that blocks oxytocin receptors during labor. Which stage of labor will be most directly affected and why?

Accepted Answer

Dilation and expulsion stages, because oxytocin is required for strong uterine contractions

Question 8

Which of the following is a correct sequence of fetal blood flow that bypasses the nonfunctional fetal lungs?

Accepted Answer

Right atrium → foramen ovale → left atrium → systemic circulation

Question 9

Which of the following best describes the role of brown fat in the neonate?

Accepted Answer

It generates heat to help maintain body temperature after birth

Question 10

A researcher blocks the acrosome reaction in sperm. What is the most likely outcome for fertilization?

Accepted Answer

Sperm will be unable to penetrate the zona pellucida, preventing fertilization

Question 11

Which of the following best explains why colostrum is important for a newborn?

Accepted Answer

It provides antibodies that help protect the infant from infection

Question 12

If the syncytiotrophoblast fails to secrete adequate hCG, which of the following is the most likely consequence?

Accepted Answer

The corpus luteum will degenerate, leading to menstruation and loss of the embryo

Question 13

Which event marks the transition from the pre-embryonic to the embryonic stage?

Accepted Answer

Gastrulation and the formation of the three germ layers

Question 14

A newborn is unable to produce sufficient prolactin. Which process will be most directly impaired?

Accepted Answer

Milk production by the mammary glands

Question 15

Which of the following best describes the function of the ductus venosus in fetal circulation?

Accepted Answer

It shunts oxygenated blood from the umbilical vein directly to the inferior vena cava, bypassing the liver

Question 16

Which of the following is a direct result of the cortical reaction during fertilization?

Accepted Answer

The zona pellucida hardens, preventing entry of additional sperm

Question 17

A woman experiences a failure of the positive feedback loop involving oxytocin during labor. Which of the following is the most likely outcome?

Accepted Answer

Weakened or stalled uterine contractions, prolonging labor

Question 18

Which of the following best explains why breast milk supports the infant's microbiome?

Accepted Answer

It contains prebiotics and beneficial bacteria that promote healthy gut flora

Question 19

A blastocyst fails to implant into the uterine wall. Which of the following will NOT occur?

Accepted Answer

Differentiation of trophoblast cells into cytotrophoblast and syncytiotrophoblast

Question 20

Which of the following best describes the main physiological purpose of the placental stage of labor?

Accepted Answer

To deliver the placenta and constrict uterine blood vessels, preventing maternal hemorrhage

Development and Heredity: Stages, Physiology, and Adaptations

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