Physio: Fertlization, Implantion And Pregnancy

Question 1

Which structure directs the oocyte from the pelvic cavity into the fallopian tube after ovulation?
A) Uterus
B) Cervix
C) Fimbriae of the fallopian tube
D) Ovary
E) Endometrium

Answer 1

C) Fimbriae of the fallopian tube

Question 2

Following its release from the follicle, the oocyte is primarily transported through the infundibulum into the ampulla of the fallopian tube by which mechanisms?
A) Peristaltic contractions of the uterus
B) Gravity alone
C) Muscular contractions of the fallopian tube and ciliary movement of the tubular epithelium
D) Sperm motility
E) Ovarian ligament contractions

Answer 2

C) Muscular contractions of the fallopian tube and ciliary movement of the tubular epithelium

Question 3

Which part of the spermatozoon contains hydrolytic enzymes to facilitate penetration into the oocyte?
A) Tail
B) Midpiece
C) Nucleus
D) Acrosome
E) Plasma membrane

Answer 3

C) Nucleus

Question 4

Which part of the spermatozoon provides the ATP required for swimming action?
A) Head
B) Midpiece
C) Tail (flagellum)
D) Acrosome
E) Plasma membrane

Answer 4

B) Midpiece (containing mitochondria)

What about the tail?
Tail has micro tubules for change of direction of tail during swimming action

Question 5

What is the first step in the process of fertilization listed in the source?
A) Adherence of sperm to the zona pellucida
B) Penetration of sperm through the zona pellucida
C) Chemoattraction of sperm to the ovum
D) Fusion of sperm with the cell membrane of the ovum
E) Release of the sperm nucleus into the ovum cytoplasm

Answer 5

C) Chemoattraction of sperm to the ovum

Question 6

The zona pellucida is described as a mucopolysaccharide membrane that surrounds which part of the ovum?

A) Nucleus
B) Mitochondria
C) Cytoplasm
D) Plasma membrane
E) Cortical granules

Answer 6

D) Plasma membrane

Question 7

Penetration of sperm through the zona pellucida is facilitated by which reaction?
A) Cortical reaction
B) Decidual reaction
C) Acrosome reaction
D) Capacitation
E) Implantation reaction

Answer 7

C) Acrosome reaction

Question 8

The acrosomal reaction involves the breakdown of the acrosome, described as a lysosome-like organelle on the head of the sperm. This reaction is followed by what?
A) Fusion with the ovum membrane
B) Binding to a sperm receptor in the zona
C) Release of proteolytic enzymes
D) Completion of Meiosis II
E) Formation of pronuclei

Answer 8

C) Release of proteolytic enzymes

Facilitate penetration of sperm through zona pellucida

Question 9

Immediately upon fertilization, what process does the secondary oocyte complete?
A) Meiosis I
B) Mitosis
C) Meiosis II
D) Cleavage
E) Syncytiotrophoblast formation

Answer 9

C) Meiosis II

Question 10

The completion of Meiosis II generates the ovum and which other cell?
A) Primary oocyte
B) Spermatid
C) Secondary polar body
D) First polar body
E) Zygote

Answer 10

C) Secondary polar body

Question 11

After completing Meiosis II, the ovum contains 23 maternal chromosomes. How does the diploid genotype of 46 chromosomes (zygote) result?
A) The ovum replicates its chromosomes.
B) The 23 maternal chromosomes pair with
23 paternal chromosomes from the spermatozoa.
C) The ovum fuses with the first polar body.
D) The ovum absorbs chromosomes from the surrounding fluid.
E) Mitotic division occurs immediately.

Answer 11

B) The 23 maternal chromosomes pair with
23 paternal chromosomes from the spermatozoa.

Question 12

The second meiotic division in the secondary oocyte is triggered by an increase in the intracellular levels of which ion upon fusion of sperm with the plasma membrane?
A) Na+
B) K+
C) Ca2+
D) Cl-
E) Mg2+

Answer 12

C) Ca2+

Question 13

A fertilized egg containing two pronuclei, each with 23 chromosomes (one from sperm, one from oocyte), is called what?
A) Ovum
B) Secondary oocyte
C) Morula
D) Blastocyst
E) Zygote

Answer 13

E) Zygote

Question 14

Which mechanism ensures that the ovum is fertilized by only one sperm cell, preventing polyspermy?
A) Chemoattraction
B) Capacitation
C) Cortical reaction
D) Acrosome reaction
E) Decidual reaction

Answer 14

C) Cortical reaction

To prevent polyspermy, enzymes release cortical granules

Question 15

The cortical reaction involves the release of enzymes from which structures located beneath the oocyte membrane?

A) Mitochondria
B) Zona pellucida
C) Blastocele
D) Cortical granules
E) Endoplasmic reticulum

Answer 15

D) Cortical granules

Question 16

Exocytosis of enzymes from the cortical granules into the perivitelline space causes what change to the zona pellucida?
A) It becomes thinner.
B) It dissolves completely.
C) It becomes harder due to cross-linking of glycoproteins.
D) It increases its permeability to sperm.
E) It changes color.

Answer 16

C) It becomes harder due to cross-linking of glycoproteins, — allowing sperm not to pass through

Question 17

Polyspermic embryos are described as abnormal and usually do not develop beyond which stage?

A) Blastocyst
B) Implantation
C) Early cleavage stages
D) Morula
E) Zygote formation

Answer 17

C) Early cleavage stages

Question 18

What is the process called where sperm gain the ability to fertilize eggs during passage through the female reproductive tract?
A) Acrosome reaction
B) Cortical reaction
C) Decidualization
D) Capacitation
E) Implantation

Answer 18

D) Capacitation

Question 19

Capacitation is achieved through the removal of factors present in the sperm membrane that are dissolved in cholesterol. These factors are acquired in which structures?

A) Ovary and fallopian tube
B) Uterus and cervix
C) Epididymis and seminal vesicles
D) Testes and vas deferens
E) Prostate gland and bulbourethral gland

Answer 19

C) Epididymis and seminal vesicles

Question 20

At approximately 48-96 hours after fertilization, repeated cleavage divisions result in a ball of about eight cells called what?
A) Zygote
B) Blastomere
C) Blastocyst
D) Morula
E) Embryoblast

Answer 20

D) Morula

Question 21

After arriving in the uterus, the morula remains unattached for about two days, floating free and receiving nutrients from the intrauterine fluid. By approximately what day after fertilization is the morula converted into a blastocyst?
A) Day 1
B) Day 3
C) Day 4
D) Day 6
E) Day 8

Answer 21

D) Day 6

Question 22

The blastocyst is described as a hollow structure containing about 100 cells. The fluid-filled cavity within the blastocyst is called the:
A) Amniotic cavity
B) Yolk sac
C) Blastocele
D) Chorionic cavity
E) Decidual space

Answer 22

C) Blastocele

Question 23

On approximately what day after fertilization does the blastocyst implant into the uterine wall?
A) Day 3
B) Day 5
C) Day 7
D) Day 9
E) Day 14

Answer 23

C) Day 7

Question 24

Prior to implantation, the blastocyst undergoes important changes including the loss of the zona pellucida and differentiation of cells into the trophoblast and which other group of cells?

A) Syncytiotrophoblast
B) Cytotrophoblast
C) Endometrium
D) Embryoblast
E) Decidua

Answer 24

D) Embryoblast

Question 25

What is the first stage of implantation, characterized by loose connections between the trophoblast and the endometrium? A) Adhesion B) Invasion C) Apposition D) Decidualization E) Differentiation

Answer 25

C) Apposition — The (—) charged trophoblast connect to the endometrium

Question 26

During the adhesion stage of implantation, the trophoblast differentiates into the cytotrophoblast and which other layer? A) Embryoblast B) Syncytiotrophoblast C) Endoderm D) Mesoderm E) Ectoderm

Answer 26

B) Syncytiotrophoblast They contain microvilli that attach to the endormetion by ligand- receptor interactions

Question 27

A group of endometrium cells at the site of implantation develop hypertrophy and contain large amounts of glycogen and lipids. These cells are called: A) Trophoblast B) Embryoblast C) Decidua D) Cytotrophoblast E) Syncytiotrophoblast

Answer 27

C) Decidua

Question 28

Decidualization of endometrial cells is caused by which hormone? A) Estrogen B) Progesterone C) hCG (human chorionic gonadotropin) D) Oxytocin E) Relaxin

Answer 28

B) Progesterone If progesterone is absent, decidualization does not occur

Question 29

The decidual reaction, occurring as the blastocyst implants, involves several changes. Which of the following is listed as part of the decidual reaction? A) Decreased capillary permeability B) Constriction of blood vessels C) Atrophy of endometrial glands D) Dilation of blood vessels and increased capillary permeability E) Increased smooth muscle contraction

Answer 29

D) Dilation of blood vessels and increased capillary permeability Also, edema and proliferation of endometrial glandular and epithelial cells.

Question 30

The decidual reaction is induced by multiple agents produced by the blastocyst, including steroids, prostaglandins, and what other category of molecules? A) Antibodies B) Hormones from the mother C) Neurotransmitters D) Growth factors E) Electrolytes

Answer 30

D) Growth factors

Question 31

In the invasion stage of implantation, which cells release proteolytic enzymes that digest pathways between endometrial cells, allowing penetration into the depth of the endometrium? A) Cytotrophoblast cells B) Embryoblast cells C) Syncytiotrophoblast cells D) Decidual cells E) Endometrial stromal cells

Answer 31

C) Syncytiotrophoblast cells Once pathway have been digest, the rods of the trophoblast attach into the holes and pathway digest and penetrate into the endometrium.

Question 32

By approximately what day after fertilization is the blastocyst completely buried in the endometrium? A) Day 5-7 B) Day 7-10 C) Day 10-14 D) Day 14-21 E) Day 21-28

Answer 32

B) Day 7-10

Question 33

At approximately week 2-3, the embryoblast differentiates into three germ layers. Which layer will form the epidermis, its appendages, and the entire nervous system? A) Endoderm B) Mesoderm C) Ectoderm D) Trophoblast E) Syncytiotrophoblast

Answer 33

C) Ectoderm

Question 34

At approximately week 2-3, the embryoblast differentiates into three germ layers. Which layer will form the lining of the digestive system? A) Endoderm B) Mesoderm C) Ectoderm D) Trophoblast E) Syncytiotrophoblast

Answer 34

A) Endoderm

Question 35

At approximately week 2-3, the embryoblast differentiates into three germ layers. Which layer will form the bulk of the body? A) Endoderm B) Mesoderm C) Ectoderm D) Trophoblast E) Syncytiotrophoblast

Answer 35

B) Mesoderm

Question 36

During the first 12 weeks of pregnancy, when the embryo is small, metabolic fuel is provided by the digestion of nutrient-rich endometrial cells at the implantation site. What is this mode of nutrition called? A) Placental nutrition B) Amniotic fluid nutrition C) Yolk sac nutrition D) Trophoblastic nutrition E) Decidual nutrition

Answer 36

D) Trophoblastic nutrition

Question 37

What serves as the organ of exchange between the mother and fetus for the rest of pregnancy after approximately 12 weeks? A) Yolk sac B) Amnion C) Umbilical cord D) Decidua basalis E) Placenta

Answer 37

E) Placenta

Question 38

The maternal part of the placenta is formed by the decidua basalis. What forms the embryonic part? A) Amnion B) Umbilical cord C) Chorion frondosum D) Yolk sac E) Embryoblast

Answer 38

C) Chorion frondosum

Question 39

What forms the placental barrier that separates maternal and fetal blood, preventing mixing? A) The entire chorion and amnion B) The syncytiotrophoblast layer only C) The decidua basalis layer only D) The layer of trophoblast cells in the villi and the layer of endothelial cells in the fetal capillaries E) The uterine wall and the blastocyst outer membrane

Answer 39

D) The layer of trophoblast cells in the villi and the layer of endothelial cells in the fetal capillaries