Biology

Embryonic Development

621 Questions

Embryonic development questions cover the biological processes of gamete fusion, germ layer formation, and fetal maturation. The focus lies in identifying extraembryonic structures, trophoblast functions, and sequential developmental stages. This specialized topic appears regularly in biology screening tests and medical entrance examinations.

Germ layer formationBlastocyst implantationExtraembryonic structuresFetal development stagesReproductive physiology

Embryonic Development Questions

Multiple choice

In mammals, generally which of the following develop into the placenta?

  1. Trophectoderm

  2. Inner cell mass of the blastocyst

  3. Decidua

  4. Myoblast cells

  5. Stromal cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The developing embryo has two main populations of cells: an inner cell mass and a trophectoderm. The trophectoderm cells lie at the outer surface of the developing embryo and will become the placenta.

Multiple choice

Which among the following statements regarding the blastula stage is incorrect?

  1. The blastocyst contains an embryoblast.

  2. The blastula stage of early embryo development begins with the appearance of the blastocoele.

  3. In the mammalian blastocyst, there are numerous lineages that give rise to later tissue development.

  4. Mammalian embryos undergo compaction around the 8-cell stage.

  5. The tight junctions arise after the polarity of epithelial cells is established.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the mammalian blastocyst, there are three lineages that give rise to later tissue development. The epiblast gives rise to the fetus itself while the trophoblast develops into part of the placenta and the primitive endoderm becomes the yolk sac.

Multiple choice

In the course of development, the blastocoele becomes __________.

  1. gestational sac

  2. intraembryonic coelom

  3. septum primum

  4. primary yolk sac

  5. chorionic cavity
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Around the 9th day, cells from the hypoblast spread around the blastocoele, forming the exocoelomic or Heuser's membrane. When the blastocoele is surrounded by this membrane, it is referred to as the primary yolk sac or exocoelomic cavity.

Multiple choice

Trophoblast is the layer of extraembryonic ectoderm which nourishes the embryo or develops into fetal membranes with nutritive functions. In mammals, during the second week of development, the trophoblast differentiates into __________.

  1. syncytiotrophoblast

  2. ectoderm

  3. endoderm

  4. intraembryonic mesoderm

  5. glochidium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The trophoblast gives rise to both the syncytiotrophoblast and the cytotrophoblast, as well as the extraembryonic mesoderm. The ectoderm is a derivative of the epiblast, and the secondary yolk sac comes from endoderm cells that line the exocoelomic cavity or the primitive yolk sac.

Multiple choice

Oropharyngeal membrane is a transient ectodermal membrane formed in embryos. The intraembryonic coelom located cranial to the oropharyngeal membrane becomes _________.

  1. oral cavity

  2. pericardial cavity

  3. tongue

  4. stomodeum

  5. nasal cavity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cardiogenic region lies cranial to the prochordal plate and its descendant, the oropharyngeal membrane. The heart tubes form on the endoderm side of intraembryonic coelom in the cardiogenic region. Following the head and lateral body folding, heart and its portion of intraembryonic coelom called pericardial cavity lie in the chest.

Multiple choice

Blastema formation occurs in the process of?

  1. Embryo genesis

  2. Regeneration

  3. Ulceration

  4. Reproduction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blastema formation occurs in regeneration. It is the cellular aggregation from which new structures arise

Multiple choice

What happens in pre-functional state of development?

  1. Newborn becomes an adult

  2. Adult performs all metabolic functions to remain alive

  3. Adult reproduces individuals of its kind

  4. The size of embryo increases

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The size of embryo increases in pre-functional state of development

Multiple choice

Wharton's jelly is a specialised tissue serving many purposes for the developing fetus. The connective tissue associated with Wharton's Jelly is _________________________.

  1. dense regular connective tissue

  2. reticular connective tissue

  3. dense irregular tissue

  4. adipose tissue

  5. mucous connective tissue
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Mucous connective tissue is a type of connective tissue found during fetal development. It is composed mainly of ground substance with few cells or fibers. It is most easily found as a component of Wharton's jelly. Mucous connective tissue forms the umbilical cord.

Multiple choice

The mesenchyme developing just below the germinal epithelium is the origin of which analogous cell types?

  1. Ovarian tissue

  2. Sex cords

  3. Sertoli and granulosa cells

  4. Spermatogonia and oogonia

  5. Leydig and thecal cells
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Mesenchyme arising beneath the germinal epithelium in the testes is the precursor to testicular interstitial cells, or Leydig cells, while in the ovaries it is the precursor to ovarian stroma or thecal cells.

Multiple choice

The Müllerian ducts (or paramesonephric ducts) are paired ducts of mesodermal origin in the embryo. Which among the following structures originate(s) from the Mullerian ducts?

  1. Upper two-thirds of the vagina

  2. Uterus

  3. Ovaries

  4. Urinary bladder

  5. Urogenital sinus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Once the Mullerian ducts have reached the urogenital sinus and the vaginal plate has formed the ducts will begin to fuse centrally. This forms the body of the uterus.

Multiple choice

Which of the following characterises development, starting with the head and brain areas and moving downward?

  1. Critical development

  2. Cephalocaudal development

  3. Progressive development

  4. Teratology development

  5. Proximodistal development
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cephalocaudal development in an infant characterises development as starting with the head and brain areas and moving downwards. He gains control of his head movement, then neck, shoulders, back, hips, legs and feet.

Multiple choice

The blastocyst is a structure formed in the early development of all the mammals. It possesses an inner cell mass which subsequently gives rise to _________.

  1. amnion

  2. chorion

  3. embryo

  4. allantois

  5. trophoblast
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An embryo is a multicellular diploid structure in its earliest stage of development, from the time of the first cell division until birth. The internal cluster of cells forming the blastocyst later forms an embryo.

Multiple choice

In a female during the pregnancy the blastocyst digests its way through the rich lining of the uterine cavity called ____________ and slowly burrows into the wall of the uterus.

  1. Endometrium

  2. Cervix

  3. Oviduct

  4. Perimetrium

  5. Myometrium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is the lining of the inside of the uterus. During the follicular phase of the menstrual cycle, the endometrium thickens in preparation to accept an embryo should conception occur. In a female, during the pregnancy, the blastocyst digests its way through the endometrium.