Question 1

During gestation, the digestive system develops from the layer of cells called the:

Accepted Answer

The endoderm gives rise to the epithelial linings of the digestive and respiratory tracts as well as associated organs such as the liver and pancreas.

Question 2

The umbilical cord:

Accepted Answer

The umbilical cord is a flexible cord that connects the embryo or fetus to the placenta, which provides oxygen and nutrients to the developing embryo or fetus. It also carries waste products away from the embryo or fetus back to the mother's body for elimination.

Question 3

The germinal period of prenatal development ends with:

Accepted Answer

The germinal period of prenatal development begins at conception and lasts for approximately two weeks until implantation of the fertilized egg in the uterine wall. Therefore, the germinal period ends with implantation in the uterine wall (Choice C). The formation of major organ systems (Choice D) occurs during the embryonic period of prenatal development, which follows the germinal period. Birth (Choice A) marks the end of the entire prenatal period, while the first cell division (Choice B) occurs during the initial stages of the germinal period.

Question 4

The umbilical cord is filled with a substance called:

Accepted Answer

The substance in the umbilical cord is called Wharton's jelly, which provides cushioning and protection for the blood vessels in the cord. Baldwin's effect and uterine waste are not substances found in the umbilical cord, and though amniotic fluid surrounds the baby in the womb, it is not contained within the umbilical cord.

Question 5

The cephalocaudal pattern of development refers to which pattern of body development?

Accepted Answer

The cephalocaudal pattern of development refers to the pattern of growth and development that begins with the head and moves down towards the feet. This is evident in the way that infants gain control of their head and neck muscles before developing control of their torso, arms, and legs.

Question 6

The placenta acts as a(n):

Accepted Answer

The placenta acts as a barrier and filter between the mother's blood and the developing organism, preventing the transfer of harmful substances to the fetus.

Question 7

The ____________ period lasts for approximately 6 weeks after implantation.

Accepted Answer

The embryonic period begins after the germinal period (which lasts for the first 2 weeks after fertilization) and lasts until the end of the 8th week of pregnancy, which is approximately 6 weeks after implantation. During this time, the major organs and systems of the body begin to form.

Question 8

What is the primary function of the umbilical cord?

Accepted Answer

The umbilical cord serves as a conduit for blood flow between the developing embryo and the placenta. This blood flow delivers necessary oxygen and nutrients to the embryo and removes waste products like carbon dioxide.

Question 9

A cell's environment provides information that regulates the:

Accepted Answer

The answer of A cell's environment provides information that regulates...

Question 10

The structure that provides the fetal contribution to the placenta is the:

Accepted Answer

The chorion is the outermost membrane surrounding the embryo during development and is responsible for the formation of the placenta. The other options (amnion, umbilicus, uterine lining) are not directly involved in the formation of the placenta.

Question 11

The structure that surrounds the developing organism, and holds in the fluid in which it floats, is the:

Accepted Answer

The amnion is a membrane that forms around the developing organism and holds in the amniotic fluid in which it floats. The amniotic fluid provides cushioning and protection for the developing fetus.

Question 12

The first step of the process of differentiation is the separation of the inner cell mass into two layers, the ____________ and the ____________.

Accepted Answer

The first step of differentiation is the separation of the inner cell mass into two layers: the endoderm and the ectoderm. The mesoderm is the third layer that forms later in development. Placenta is not one of the layers of differentiation.

Question 13

An early example of the interaction between biology and the environment is:

Accepted Answer

Epigenesis is the process by which the environment can influence gene expression and development. This was first proposed by Aristotle in ancient Greece, who observed that embryos develop gradually and are shaped by the environment in which they grow. This early idea of epigenesis laid the foundation for our modern understanding of how genes and the environment interact to shape the development of organisms.

Question 14

The outer layer of cells in early embryonic development is called the ____________. This layer gives rise to the outer surface of the skin, the nails, part of the teeth, the lens of the eye, and the nervous system.

Accepted Answer

The outer layer of cells in early embryonic development is called the ectoderm, which gives rise to the outer surface of the skin, the nails, part of the teeth, the lens of the eye, and the nervous system. The endoderm gives rise to the inner lining of the digestive tract and respiratory system, while the mesoderm gives rise to the muscles, bones, and other organs. Chorion is a membrane that forms around the embryo and helps form the placenta.

Question 15

The structure that transports nutrient-rich blood from the placenta to the embryo is called the:

Accepted Answer

The umbilical cord is a structure that connects the developing embryo to the placenta, allowing for the exchange of oxygen, nutrients, and waste products between the embryo and the mother's blood supply.

Question 16

Which of the following structures is the last to appear?

Accepted Answer

The answer of Which of the following structures is the...

Question 17

The embryonic period lasts for approximately ____________ weeks after implantation.

Accepted Answer

The embryonic period lasts for approximately 6 weeks after implantation.

Question 18

Which of the following develop from the part of the inner cell mass called the mesoderm?

Accepted Answer

Bones and muscles develop from the mesoderm layer.

Question 19

Epigenesis is the process by which:

Accepted Answer

Epigenesis refers to the development of an individual organism from a single fertilized egg cell through a process that involves environmental factors as well as genetic information. Therefore, new forms of the zygote can emerge from the interactions of the preceding form and its current environment, making option D the best choice. Option A is incorrect because meiosis is the process of cell division that produces gametes, not zygotes. Option B is incorrect because after fertilization, the zygote does not immediately divide into four cells. Option C is incorrect because implantation occurs after the process of epigenesis has already begun.

Question 20

The first organized responses of the developing organism to the environment occur during which period?

Accepted Answer

During the embryonic period, which occurs from the second week to the eighth week after conception, the developing organism is especially sensitive to environmental influences, and the first organized responses to the environment occur during this period.

Quiz 3: Prenatal Development and Birth