1.
The prechordal plate will be the location of:
Correct Answer
C. Mouth
Explanation
The prechordal plate is a region in the early embryonic development that gives rise to the mouth. It is responsible for the formation of the oral cavity and structures associated with it, such as the lips and tongue. The heart, stomach, and spinal cord, on the other hand, develop from different regions of the embryo. Therefore, the correct answer is "Mouth".
2.
Which one of these is not formed by the neural crest?
Correct Answer
A. The CNS
Explanation
The CNS (Central Nervous System) is not formed by the neural crest. The neural crest is a group of cells that develop along the edges of the neural tube during embryonic development. It gives rise to various structures including pigment cells, the adrenal gland medulla, and peripheral ganglia. However, the CNS is formed from the neural tube itself, not the neural crest.
3.
The process by which the bilaminar disc is converted into trilaminar disc is:
Correct Answer
B. Gastrulation
Explanation
Gastrulation is the correct answer because it is the process by which the bilaminar disc, which consists of two layers (epiblast and hypoblast), is converted into a trilaminar disc. During gastrulation, the epiblast cells migrate and invaginate to form the three germ layers - ectoderm, mesoderm, and endoderm. This process is crucial for the development of various organs and tissues in the embryo.
4.
The cells by which the embryo will be nourished are:
Correct Answer
C. Decidual
Explanation
Decidual cells are the cells that form the decidua, which is the lining of the uterus during pregnancy. These cells are responsible for the nourishment and support of the developing embryo. They provide nutrients and oxygen to the embryo, as well as remove waste products. Additionally, decidual cells play a crucial role in the implantation of the embryo into the uterine wall and the formation of the placenta. Overall, decidual cells are essential for the successful development and growth of the embryo.
5.
The part involved in the formation of blood is:
Correct Answer
D. Allantois
Explanation
The allantois is involved in the formation of blood. The allantois is a structure that develops during embryonic development in mammals, birds, and reptiles. It plays a crucial role in the formation of blood vessels and the production of blood cells. The allantois connects the embryo to the developing placenta and is responsible for the exchange of gasses, nutrients, and waste products between the embryo and the mother. Additionally, it serves as a site for the production of blood cells, contributing to the formation of the circulatory system.
6.
The fluid will start to accumulate within the morula :
Correct Answer
A. 5 DAF
7.
The epiblast is formed of:
Correct Answer
C. Columnar cells
Explanation
The epiblast is formed of columnar cells. Columnar cells are elongated and have a tall, narrow shape, resembling columns. They are found in various tissues and organs of the body, including the epiblast. These cells are specialized for functions such as absorption and secretion due to their shape and arrangement. Therefore, the correct answer is columnar cells.
8.
After the blastocyst cavity is surrounded by exocoelomic membrane it is called:
Correct Answer
B. Exocoelomic cavity
Explanation
After the blastocyst cavity is surrounded by the exocoelomic membrane, it is called the exocoelomic cavity. This is the space that forms within the blastocyst, which is the early stage of development of an embryo. The exocoelomic cavity plays a crucial role in the development of the embryo, as it is involved in the formation of the yolk sac and the establishment of the circulatory system. It eventually gives rise to the primary umbilical vesicle, which is an important structure for the exchange of nutrients and waste between the mother and the developing embryo.
9.
First spontaneous movement of the embryo is in:
Correct Answer
C. 6th week
Explanation
During the 6th week of pregnancy, the embryo undergoes a significant development known as the beginning of spontaneous movement. This is when the embryo starts to make its first voluntary movements, which are often small and uncoordinated. These movements are essential for the normal development of the musculoskeletal system and the nervous system. By the 6th week, the embryo has developed enough to have the capability to move, marking an important milestone in its growth and development.
10.
The fetal period is:
Correct Answer
C. The period from 9th week till birth
Explanation
The fetal period refers to the stage of prenatal development that starts from the 9th week of gestation and continues until birth. During this period, the major organs and systems of the fetus develop and mature. It is characterized by rapid growth and refinement of structures, as well as the development of more distinct human characteristics.
11.
To diagnose any abnormality in the fetal heart we use:
Correct Answer
A. Fetal monitoring
Explanation
Fetal monitoring is used to diagnose any abnormality in the fetal heart. This involves monitoring the baby's heart rate and rhythm during pregnancy using various techniques such as electronic fetal monitoring or Doppler ultrasound. By continuously monitoring the fetal heart, healthcare providers can detect any irregularities or signs of distress, allowing for timely intervention and appropriate management. Ultrasonography, chorionic villus sampling, and cell culture are not specifically used for diagnosing abnormalities in the fetal heart.
12.
All of these can result in a variation in human species except:
Correct Answer
B. Implantation
Explanation
Implantation refers to the attachment of a fertilized egg to the lining of the uterus, which is a crucial step in pregnancy. However, implantation does not directly cause a variation in the human species. On the other hand, crossing-over during meiosis, mutations in DNA, and the mingling of chromosomes from two different individuals can all lead to genetic variations and contribute to the diversity within the human species.
13.
The blastocyst is called (later blastocyst) after:
Correct Answer
C. Hatching
Explanation
The blastocyst is called "later blastocyst" after hatching. Hatching refers to the process in which the blastocyst breaks out of its protective zona pellucida and implants itself into the uterine lining. This marks an important stage in embryonic development as it allows the blastocyst to establish a connection with the maternal blood supply and continue its growth and development. Therefore, the term "later blastocyst" is used to describe the blastocyst after it has successfully hatched.
14.
Extraembryonic Splanchnic mesoderm covers:
Correct Answer
B. Umbilical vesicle
Explanation
The extraembryonic splanchnic mesoderm covers the umbilical vesicle. This is a structure that forms during early embryonic development and is responsible for providing nutrients to the developing embryo. The splanchnic mesoderm surrounds and protects the umbilical vesicle, ensuring its proper function and development.