BIOL 252 | BIOL252 Module 9: Human Anatomy &
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. During the first trimester, which structure is primarily responsible for secreting
progesterone to maintain the endometrial lining?
A. The placenta
B. The anterior pituitary
C. The corpus luteum
D. The blastocyst trophoblast
Correct Answer: C
Explanation: The corpus luteum is the temporary endocrine structure that produces high
levels of progesterone during the early weeks of pregnancy. This hormone is vital for
maintaining the uterine environment and preventing menstruation until the placenta is
fully functional. Around week 12, the placenta takes over the primary role of steroid
hormone production. Without sufficient progesterone from the corpus luteum in the early
stages, the pregnancy would likely terminate. This transition period is often referred to as
the luteal-placental shift.
2. Which embryonic membrane is responsible for forming the structural base for the umbilical
cord and becomes part of the urinary bladder?
A. Yolk sac
B. Chorion
C. Amnion
D. Allantois
Correct Answer: D
Explanation: The allantois is a small outpocketing of embryonic tissue that develops from
the yolk sac. It serves as the structural foundation for the development of the umbilical
cord. Later in fetal development, the allantois contributes to the formation of the urinary
bladder. It plays a critical role in the early waste management and vascularization of the
embryo. Understanding the four extraembryonic membranes is essential for tracing fetal
development.
3. A patient in her third trimester experiences a significant increase in cardiac output. Which
physiological change primarily contributes to this adaptation?
A. Increased stroke volume and heart rate
,B. Decreased heart rate
C. Decreased blood volume
D. Systemic vasoconstriction
Correct Answer: A
Explanation: Maternal cardiac output increases by approximately 30 to 50 percent during
pregnancy to meet fetal oxygen demands. This increase is achieved through elevations in
both stroke volume and maternal heart rate. Blood volume also expands significantly to
support the placenta and protect against blood loss during delivery. Systemic vascular
resistance actually decreases due to the vasodilatory effects of progesterone. These
adaptations ensure adequate perfusion to both the mother’s vital organs and the growing
fetus.
4. At which stage of development does the conceptus transition from being called an embryo
to being called a fetus?
A. End of week 8
B. End of week 4
C. End of week 12
D. End of the first month
Correct Answer: A
Explanation: The embryonic period officially spans from fertilization through the eighth
week of gestation. During this time, all major organ systems begin to form in a process
known as organogenesis. Once the ninth week begins, the developing human is referred to
as a fetus until birth. The fetal period is characterized primarily by rapid growth and the
maturation of these organ systems. Distinguishing between these periods is important for
understanding developmental milestones and vulnerability to teratogens.
5. The ‘morning sickness’ often experienced during the first trimester is most closely
associated with rising levels of which hormone?
A. Relaxin
B. Human chorionic gonadotropin (hCG)
C. Oxytocin
D. Prolactin
Correct Answer: B
Explanation: Human chorionic gonadotropin is produced by the trophoblast cells and later
the chorion. Its levels peak around the end of the second month of pregnancy. High
concentrations of hCG are thought to stimulate the area postrema in the brain, leading to
, nausea. While other hormones like estrogen play a role, hCG is the primary marker linked
to these symptoms. As hCG levels stabilize later in pregnancy, most women find that
morning sickness subsides.
6. During gastrulation, the three primary germ layers are formed. Which layer is responsible
for the development of the nervous system and the epidermis?
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Hypoblast
Correct Answer: A
Explanation: Gastrulation is a critical process that establishes the three-layered embryo
consisting of ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer
and gives rise to the entire nervous system including the brain and spinal cord. It also
forms the skin’s outer layer, known as the epidermis, and various sensory organs. The
mesoderm forms muscles and bones, while the endoderm forms internal organ linings.
Accurate identification of these layers is a fundamental concept in embryology.
7. Which fetal circulatory shunt allows blood to flow directly from the right atrium to the left
atrium, bypassing the non-functional lungs?
A. Ductus venosus
B. Ductus arteriosus
C. Umbilical vein
D. Foramen ovale
Correct Answer: D
Explanation: The foramen ovale is an opening in the interatrial septum that exists during
fetal life. Since the fetal lungs are collapsed and non-functional for gas exchange, this shunt
redirects oxygenated blood. It allows blood entering the right atrium from the inferior vena
cava to pass straight into the left atrium. This bypassed blood then enters the systemic
circulation more efficiently. Upon the first breath at birth, pressure changes cause this
opening to close and become the fossa ovalis.
8. A pregnant woman reports increased joint laxity and a change in her gait. Which hormone
is primarily responsible for these skeletal changes?
A. Progesterone
B. Relaxin
C. Estrogen
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. During the first trimester, which structure is primarily responsible for secreting
progesterone to maintain the endometrial lining?
A. The placenta
B. The anterior pituitary
C. The corpus luteum
D. The blastocyst trophoblast
Correct Answer: C
Explanation: The corpus luteum is the temporary endocrine structure that produces high
levels of progesterone during the early weeks of pregnancy. This hormone is vital for
maintaining the uterine environment and preventing menstruation until the placenta is
fully functional. Around week 12, the placenta takes over the primary role of steroid
hormone production. Without sufficient progesterone from the corpus luteum in the early
stages, the pregnancy would likely terminate. This transition period is often referred to as
the luteal-placental shift.
2. Which embryonic membrane is responsible for forming the structural base for the umbilical
cord and becomes part of the urinary bladder?
A. Yolk sac
B. Chorion
C. Amnion
D. Allantois
Correct Answer: D
Explanation: The allantois is a small outpocketing of embryonic tissue that develops from
the yolk sac. It serves as the structural foundation for the development of the umbilical
cord. Later in fetal development, the allantois contributes to the formation of the urinary
bladder. It plays a critical role in the early waste management and vascularization of the
embryo. Understanding the four extraembryonic membranes is essential for tracing fetal
development.
3. A patient in her third trimester experiences a significant increase in cardiac output. Which
physiological change primarily contributes to this adaptation?
A. Increased stroke volume and heart rate
,B. Decreased heart rate
C. Decreased blood volume
D. Systemic vasoconstriction
Correct Answer: A
Explanation: Maternal cardiac output increases by approximately 30 to 50 percent during
pregnancy to meet fetal oxygen demands. This increase is achieved through elevations in
both stroke volume and maternal heart rate. Blood volume also expands significantly to
support the placenta and protect against blood loss during delivery. Systemic vascular
resistance actually decreases due to the vasodilatory effects of progesterone. These
adaptations ensure adequate perfusion to both the mother’s vital organs and the growing
fetus.
4. At which stage of development does the conceptus transition from being called an embryo
to being called a fetus?
A. End of week 8
B. End of week 4
C. End of week 12
D. End of the first month
Correct Answer: A
Explanation: The embryonic period officially spans from fertilization through the eighth
week of gestation. During this time, all major organ systems begin to form in a process
known as organogenesis. Once the ninth week begins, the developing human is referred to
as a fetus until birth. The fetal period is characterized primarily by rapid growth and the
maturation of these organ systems. Distinguishing between these periods is important for
understanding developmental milestones and vulnerability to teratogens.
5. The ‘morning sickness’ often experienced during the first trimester is most closely
associated with rising levels of which hormone?
A. Relaxin
B. Human chorionic gonadotropin (hCG)
C. Oxytocin
D. Prolactin
Correct Answer: B
Explanation: Human chorionic gonadotropin is produced by the trophoblast cells and later
the chorion. Its levels peak around the end of the second month of pregnancy. High
concentrations of hCG are thought to stimulate the area postrema in the brain, leading to
, nausea. While other hormones like estrogen play a role, hCG is the primary marker linked
to these symptoms. As hCG levels stabilize later in pregnancy, most women find that
morning sickness subsides.
6. During gastrulation, the three primary germ layers are formed. Which layer is responsible
for the development of the nervous system and the epidermis?
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Hypoblast
Correct Answer: A
Explanation: Gastrulation is a critical process that establishes the three-layered embryo
consisting of ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer
and gives rise to the entire nervous system including the brain and spinal cord. It also
forms the skin’s outer layer, known as the epidermis, and various sensory organs. The
mesoderm forms muscles and bones, while the endoderm forms internal organ linings.
Accurate identification of these layers is a fundamental concept in embryology.
7. Which fetal circulatory shunt allows blood to flow directly from the right atrium to the left
atrium, bypassing the non-functional lungs?
A. Ductus venosus
B. Ductus arteriosus
C. Umbilical vein
D. Foramen ovale
Correct Answer: D
Explanation: The foramen ovale is an opening in the interatrial septum that exists during
fetal life. Since the fetal lungs are collapsed and non-functional for gas exchange, this shunt
redirects oxygenated blood. It allows blood entering the right atrium from the inferior vena
cava to pass straight into the left atrium. This bypassed blood then enters the systemic
circulation more efficiently. Upon the first breath at birth, pressure changes cause this
opening to close and become the fossa ovalis.
8. A pregnant woman reports increased joint laxity and a change in her gait. Which hormone
is primarily responsible for these skeletal changes?
A. Progesterone
B. Relaxin
C. Estrogen
