Deck 24: Pregnancy and Development

Question 1

Describe the major functions of the placenta.

Answer 1

The physiological as well as the mechanical attachment found among the fetus and maternal tissues for excretion, nutrition as well as for the respiration purpose are known as placenta. Placenta forms an intimate connection between the wall of uterus and the membranes of the fetus. Fetal placenta is formed by the chorion membrane of the fetus combines with the maternal placenta, which is formed by the wall of the uterus of the mother results into the formation of the placenta.
The intimacy between the fetal and the maternal placenta is very strong. The chorion membrane of the fetus has villi, which are completely dipped into the blood of the mother. Placenta facilitates the close contact of the mother's blood with the fetus blood but mixing of the mother and the fetus blood never takes place. Maternal blood supplies the food, nutrients and oxygen to the fetus and takes away all the waste present in the fetus blood. The fetus is connected to the placenta by umbilical cord.
Major functions of the placenta are as follows:
The transport of the nutrients to the fetus from the mother's blood is done by placenta.
Placenta also helps in the transfer of oxygen from mother blood to the fetus and carbon dioxide from fetus to the mother. Various enzymes are also secreted by placenta like, estrogen, progesterone, thus it also functions like an endocrine organ.
Placenta has the function of storage as it stores iron, fats and glycogen. Placenta also facilitates the transfer of immunity from the mother to the fetus against various diseases. Various nitrogenous wastes are also diffused through the placenta from fetus blood to the mother blood for the excretion purpose.

Question 2

An implantation occurring somewhere other than in the uterus is called

A) placenta previa
B) an ectopic pregnancy
C) an abortion
D) hydramnios

Answer 2

B
Placenta previa is a condition, which occurs during pregnancy. Under this condition the abnormal implantation of the placenta in the uterus takes place because of, which the uterine cervix get covered. Causes of the placenta previa are still unknown. It usually occurs, during the third trimester of the pregnancy and causes the painless bleeding. Ultrasonography is the techniques used to diagnose the placenta previa.
An abortion is type of medical process and used to terminate the pregnancy. Spontaneous abortion or the natural abortions are those, which occur on its own and also known as the miscarriage.
Hydramnios is a condition arises due to the excess accumulation of the amniotic fluid around the fetus. The amniotic fluid provides the protection to the fetus inside of the uterus. Hydramnios may cause the early labor.
Hence, the options A, C and D are incorrect.
Ectopic pregnancy causes the implantation of the embryo to the locations other than the uterus. Mostly in the case of ectopic pregnancy the transplantation of the embryo takes place in the fallopian tube. Causes of the ectopic pregnancy are related to the history of endometriosis, female organ surgery due to some infection and deformed fallopian tubes. Symptoms of ectopic pregnancy include the pain in the abdomino-pelvic region, cramping in pelvic region and abnormal bleeding from vagina.

Question 3

The solid ball of cells after several rounds of cell division is called a

A) blastocyst
B) morula
C) blastula
D) chorion

Answer 3

B
Blastocyst forms after approximately 5 days of the conception. Blastocyst is a hollow cell ball, which attaches with the uterus endometrium. One layer of the blastocyst is made up of the trophoblast cells. Trophoblast cells have flat and large structure. Blastocyst has inner cell mass, which is composed of the cluster of twenty to thirty round shaped cells and fluid is also present inside of blastocyst. Inner cell mass of the blastocyst give rise to the embryo, whereas the outer layer forms the placenta and other tissues required for the development of the fetus.
Blastula is a sphere of blastomeres and it is hollow from inside. Blastula is formed due to the frequent cleavage of the morula, which is in turn formed by the cleavage of the fertilized egg. Cells of the blastula construct a covering made up of the epithelial cell, which is known as the blastoderm. Blastoderm encloses the fluid cavity known as blastocoel.
Chorion is a membrane, which exists during the period of the pregnancy. It acts as a fetal membrane and present between the mother and the developing fetus. Combination of the amnion and chorion forms the sac called as the amniotic sac.
Hence, the options A, C and D are incorrect.
Morula is formed by the sequence of the cleavage and divisions of the single celled fertilized egg. It is a solid mass or ball made up of approximately sixteen blastomeres or the cells. Embryo's extra embryonic structures are formed by the blastomeres present on the outer surface of the morula. Morula usually forms three days after the conception.

Question 4

A developing fetus may be distinguished as either male or female at

A) 8 weeks of development
B) 12 weeks of development
C) 4 months of development
D) 6 months of development

Question 5

Explain which body system and other parts of the body develop from ectodermal cells.

Question 6

Which of the following hormones is involved in milk production?

A) estrogen
B) progesterone
C) relaxin
D) prolactin

Question 7

A blastocyst is a

A) solid ball of cells
B) hollow ball of cells
C) portion of the ovary
D) part of the penis

Question 8

Describe fetal circulation.

Question 9

Most of the blood in the pulmonary trunk bypasses the lungs by entering a fetal vessel called the

A) foramen ovale
B) ductus venosus
C) ductus arteriosus
D) umbilical vein

Question 10

Explain the stages of labor.

Question 11

What substance fills the space between the amnion and embryonic disc?

A) amniotic fluid
B) aqueous fluid
C) allantois
D) colostrum

Question 12

A couple that has been trying to have a baby for 3 years goes to see a fertility specialist. After testing, the woman tests normal, but the man is shown to be "subfertile." He has a very low sperm count.
How can this affect the couple's chances of having a baby?

Question 13

Define the terms karyotypes, autosomes, and heterozygous.

Question 14

Describe the process of fertilization.

Question 15

The hormone that increases the flexibility of the symphysis pubis and causes dilation of the cervix during pregnancy is

A) estrogen
B) luteinizing hormone
C) human placental lactogen
D) relaxin

Question 16

The union of a sperm cell and an egg cell is called

A) cleavage
B) implantation
C) plantation
D) fertilization

Question 17

Describe the three major modes of inheritance.

Question 18

A couple that has been trying to have a baby for 3 years goes to see a fertility specialist. After testing, the woman tests normal, but the man is shown to be "subfertile." He has a very low sperm count.
What can the physician suggest to this couple that may help the woman become pregnant?

Question 19

The first stage of labor is the

A) dilation stage
B) expulsion stage
C) decidual stage
D) neonate stage

Question 20

Describe cleavage and blastocyst formation.

Question 21

Explain environmental factors that may affect inherited traits and conditions.

Question 22

The process of cell division that occurs after fertilization is called

A) blastulation
B) cleavage
C) embryogenesis
D) implantation

Question 23

The time spent in prenatal development is referred to as

A) implantation
B) embryogenesis
C) plantation
D) gestation

Question 24

What is the function of gastrulation?

Question 25

An individual who has two identical alleles of a gene is referred to as

A) homozygous
B) homologous
C) heterozygous
D) autosome

Question 26

The inner cell mass of the blastocyst will form

A) the embryo
B) the placenta
C) the morula
D) blood vessels of the placenta

Question 27

Chromosomes that are not sex chromosomes are referred to as

A) heterozygous
B) homozygous
C) homologous
D) autosomes