BIO 351 Embryology & Development Exam Questions &
Answers 2026 | Complete Study Guide | Graded A+
1. Which area of the neural tube is active in division of neuronal progenitors?
pial surface
central canal
ventricular surface
2. Describe the sequence of events that occurs during heart morphogenesis
leading to the formation of the heart structure.
The first step is the formation of the linear heart tube, followed by
looping and septation.
The sequence begins with the specification of the cardiogenic
mesoderm, followed by the formation of heart fields, then the linear
heart tube, which undergoes looping and septation.
Heart morphogenesis begins with septation and ends with the
specification of the cardiogenic mesoderm.
The heart morphogenesis starts with the formation of the second
heart field, followed by looping and septation.
3. What is the first step in the process of heart morphogenesis?
Specification of cardiogenic mesoderm
Formation of the second heart field
Formation of the linear heart tube
Septation
,4. Which of the following tissues is formed from the trophoblast cells of the
embryo?
ectoderm
endoderm
placenta
mesoderm
5. Which of the following processes occurs when a salamander regenerates a
lost limb
a new salamander develops from the lost limb
the homeotic genes of the regenerating limb are expressed
certain cells in the limb dedifferentiate, divide, and then
redifferentiate to form a new limb
the homeotic genes of the regenerating cells turn off
6. What is the primary reason infants born between 25-30 weeks gestation
experience respiratory distress?
disruption of diaphragm and intercostal muscle determination
branching morphogenesis of the lung is inhibited
insufficient production of pulmonary surfactant
aberrant lung bud specification
7. A male client visits a fertility clinic after one year of attempting unsuccessfully
to impregnate his wife. Which of the following is a risk factor associated with
male infertility?
Sperm density about 20 million/mL
, Morphology of sperm within normal limits
2 to 5 mL of semen ejaculated
Azospermia or oligospermia
8. Describe the significance of Wnt genes in the context of morphollactic
regeneration in hydra.
Wnt genes play a crucial role in specifying the formation of head
structures during the regeneration process.
Wnt genes inhibit the regeneration of tissues in hydra.
Wnt genes are not involved in the regeneration process of hydra.
Wnt genes are responsible for the regeneration of foot structures in
hydra.
9. Toxoplasmosis is often linked to hydrocephalus, a potentially harmful
condition that directly results from:
loss of lung surfactant
loss of nodal cells
obstruction of blood flow to the placenta
Obstruction of CSF flow
10. Lack of production of in a fetus before 35 weeks causes respiratory distress
syndrome
Mucous
Urine
Surfactant
Air in blood
, 11. If a scientist is studying a species that exhibits high levels of tissue repair after
injury, what implications might this have for understanding human healing
processes?
It would have no relevance to human healing processes.
It would suggest that humans can regenerate limbs like this species.
It could provide insights into improving human wound healing and
tissue regeneration therapies.
It would indicate that human healing is less effective than in all other
species.
12. One of the many reasons for early trimester miscarriage is luteal
insufficiency, a condition that inhibits the luteal phase of the ovarian cycle. As
a result, the corpus luteum never fully develops or releases any hormones.
Which of the following is also a likely result of luteal insufficiency?
high levels of progesterone
endometrium does not maintain thickened lining
dramatic spike in LH
chronic low FSH
13. Describe the role of the trophoblast in the development of the placenta and
its significance in nutrient transfer.
The trophoblast forms the outer layer of the blastocyst and is
crucial for the implantation of the embryo and the formation of the
placenta, facilitating nutrient transfer between maternal and fetal
blood.
The trophoblast generates the mesoderm, which is involved in muscle
and bone development.
Answers 2026 | Complete Study Guide | Graded A+
1. Which area of the neural tube is active in division of neuronal progenitors?
pial surface
central canal
ventricular surface
2. Describe the sequence of events that occurs during heart morphogenesis
leading to the formation of the heart structure.
The first step is the formation of the linear heart tube, followed by
looping and septation.
The sequence begins with the specification of the cardiogenic
mesoderm, followed by the formation of heart fields, then the linear
heart tube, which undergoes looping and septation.
Heart morphogenesis begins with septation and ends with the
specification of the cardiogenic mesoderm.
The heart morphogenesis starts with the formation of the second
heart field, followed by looping and septation.
3. What is the first step in the process of heart morphogenesis?
Specification of cardiogenic mesoderm
Formation of the second heart field
Formation of the linear heart tube
Septation
,4. Which of the following tissues is formed from the trophoblast cells of the
embryo?
ectoderm
endoderm
placenta
mesoderm
5. Which of the following processes occurs when a salamander regenerates a
lost limb
a new salamander develops from the lost limb
the homeotic genes of the regenerating limb are expressed
certain cells in the limb dedifferentiate, divide, and then
redifferentiate to form a new limb
the homeotic genes of the regenerating cells turn off
6. What is the primary reason infants born between 25-30 weeks gestation
experience respiratory distress?
disruption of diaphragm and intercostal muscle determination
branching morphogenesis of the lung is inhibited
insufficient production of pulmonary surfactant
aberrant lung bud specification
7. A male client visits a fertility clinic after one year of attempting unsuccessfully
to impregnate his wife. Which of the following is a risk factor associated with
male infertility?
Sperm density about 20 million/mL
, Morphology of sperm within normal limits
2 to 5 mL of semen ejaculated
Azospermia or oligospermia
8. Describe the significance of Wnt genes in the context of morphollactic
regeneration in hydra.
Wnt genes play a crucial role in specifying the formation of head
structures during the regeneration process.
Wnt genes inhibit the regeneration of tissues in hydra.
Wnt genes are not involved in the regeneration process of hydra.
Wnt genes are responsible for the regeneration of foot structures in
hydra.
9. Toxoplasmosis is often linked to hydrocephalus, a potentially harmful
condition that directly results from:
loss of lung surfactant
loss of nodal cells
obstruction of blood flow to the placenta
Obstruction of CSF flow
10. Lack of production of in a fetus before 35 weeks causes respiratory distress
syndrome
Mucous
Urine
Surfactant
Air in blood
, 11. If a scientist is studying a species that exhibits high levels of tissue repair after
injury, what implications might this have for understanding human healing
processes?
It would have no relevance to human healing processes.
It would suggest that humans can regenerate limbs like this species.
It could provide insights into improving human wound healing and
tissue regeneration therapies.
It would indicate that human healing is less effective than in all other
species.
12. One of the many reasons for early trimester miscarriage is luteal
insufficiency, a condition that inhibits the luteal phase of the ovarian cycle. As
a result, the corpus luteum never fully develops or releases any hormones.
Which of the following is also a likely result of luteal insufficiency?
high levels of progesterone
endometrium does not maintain thickened lining
dramatic spike in LH
chronic low FSH
13. Describe the role of the trophoblast in the development of the placenta and
its significance in nutrient transfer.
The trophoblast forms the outer layer of the blastocyst and is
crucial for the implantation of the embryo and the formation of the
placenta, facilitating nutrient transfer between maternal and fetal
blood.
The trophoblast generates the mesoderm, which is involved in muscle
and bone development.
