Deck 44: Survey of Embryonic Development

Question 1

This structure surrounds the early embryo and the fluid that fills it protects the embryo.

A) amnion
B) chorion
C) allantois

Answer 1

A

Question 2

Fertilization .

A) is the process of fusion of egg and sperm
B) is the process of providing nutrients to the embryo
C) is the division of the zygote into a mass of cells
D) is the final step to occur before implantation into the uterus

Answer 2

A

Question 3

Chorionic villi look like _.

A) feathery extensions of the chorion in the uterine wall
B) blood-filled channels in the uterine wall
C) fingers stuck into the uterine wall
D) rings of chorionic canals in the uterine wall

Answer 3

A

Question 4

Implantation of the blastocyst in the uterine wall is complete by day _ after ovulation.

A) 14
B) 4
C) 7
D) 10

Question 5

This embryonic membrane provides the structural basis for the umbilical cord.

A) amnion
B) chorion
C) allantois
D) yolk sac

Question 6

This cord attaches the embryo to the placenta.

A) umbilical cord
B) yolk sac
C) allantois
D) abdominoplacental cord

Question 7

The human blastocyst consists of two populations of cells with different functions. Select the correct match between population and its function.

A) trophoblast; becomes fetal amnion
B) trophoblast; becomes yolk sac
C) inner cell mass (ICM); forms the embryo and three of the four extraembryonic membranes
D) inner cell mass (ICM); becomes fetal chorion

Question 8

The function of cleavage is to .

A) begin specialization of the cells to form specific tissues and organs
B) form the organ systems
C) increase the number of cells forming the blastocyst

Question 9

Once fertilization has occurred, the activities of development begin. The first such activity is .

A) cellular specialization
B) the formation of organ systems
C) an increase in cell number

Question 10

What organs appear very early in development?

A) skeletal muscles
B) kidneys and glands
C) lungs and alimentary canal
D) brain and heart

Question 11

The trophoblast cells of the blastocyst form the , which extends elaborate villi into the blood-filled sinusoids of the uterine wall.

A) amnion
B) yolk sac
C) chorion
D) allantois

Question 12

In the human, this germ cell layer gives rise to many of the organ systems, including the skeleton, skeletal muscles, walls of GI organs, urinary system, and circulatory system.

A) endoderm
B) mesoderm
C) ectoderm

Question 13

The placenta is formed by .

A) maternal and fetal tissues
B) maternal tissues
C) fetal tissues

Question 14

This portion of the blastocyst forms the embryo proper.

A) zona pellucida
B) trophoblast
C) morula
D) inner cell mass (ICM)

Question 15

The three primary germ layers develop during this stage of human fetal development.

A) morula
B) gastrula
C) cleavage
D) blastula

Question 16

All exchanges between mother and embryo occur _.

A) through the allantois
B) through the amniotic fluid
C) as maternal and fetal blood mix in the placenta
D) across the chorionic membranes

Question 17

In humans, the yolk sac .

A) is no longer a useful structure
B) forms the human urinary bladder
C) passes nutrients to the embryo after digesting the yolk mass
D) is the site of origin for blood cells and primordial germ cells

Question 18

The decidua basalis and decidua capsularis are portions of the uterine wall. Which is (are) involved in formation of the placenta?

A) decidua basalis
B) decidua capsularis
C) both
D) neither

Question 19

The is the final product of cleavage.

A) trophoblast
B) zygote
C) blastocyst
D) gastrula

Question 20

During the process of implantation, the inner cell mass (ICM) gives rise to three embryonic membranes. Which of the following is not one of these membranes?

A) allantois
B) chorion
C) yolk sac
D) amnion

Question 21

What is true of the structure of the human placenta?

A) It forms a belt around the embryo.
B) It is diffuse, with villi distributed over the surface of the chorion.
C) It is disc-shaped.

Question 22

In humans, this primary germ layer gives rise to the epidermis and the nervous system.

A) endoderm
B) ectoderm
C) mesoderm

Question 23

Development progresses .

A) from the head and the distal limbs towards the trunk
B) simultaneously upwards, outwards, and downwards from the trunk
C) from the midline lateral to the body walls, then proximal to distal on the limbs
D) in rostral to caudal and proximal to distal directions

Question 24

In what region of the uterus does implantation usually occur (as indicated by the position of the placenta)?

A) anywhere in the body of the uterus
B) close to the cervix
C) in the upper part of the uterus