Anatomy

Question 1

What is gestation?

Answer 1

The time required for full development of a foetus in utero

Question 2

Which period of pregnancy is known as the ‘pre-embryonic period’?

Answer 2

The first 2 weeks of prenatal development (first 2 weeks of pregnancy)

Question 3

Which period of pregnancy is known as the ‘embryonic period’?

Answer 3

3-8 weeks

Question 4

How far into gestation does the embryo become the foetus?

Answer 4

After 9 weeks up until birth

Question 5

Name the 6 events that occur during the pre-embryonic period

Answer 5

1. Fertilisation
2. Cleavage
3. Formation of Blastocyst
4. Implantation
5. Formation of Germ Disc
6. Formation of Embryonic Membranes

Question 6

During fertilisation, the reproductive tract delivers the sperm to which part of the uterine tube?

a. Egg
b. Follicle
c. Ampulla
d. Ovary

Answer 6

C. Ampulla

Question 7

How long after ovulation do the egg and sperm meet?

Answer 7

12-24 hours

Question 8

How long is an oocyte viable for? How long is a sperm viable for?

Answer 8

Oocyte - 1 day; Sperm - 3 days

Question 9

Which of these DOES NOT occur during the acrosomal reaction of fertilisation?

a. the sperm sheds its acrosomal cap
b. a foetus is formed
c. lots of enzymes released
d. the oocyte is encapsulated by the Zona pellucida and the Corona radiata

Answer 9

b. a foetus is formed

The foetus is not formed until week 9 of the pregnancy.

The acrosomal reaction involves the shedding of the acrosomal cap, leading to a large release of enzymes that allow the oocyte to be encapsulated by the Corona radiata & the Zona pellucida

Question 10

How long does sperm capacitation take?

Answer 10

6-8 hours

Question 11

Which molecules, released by the sperm, allow it to penetrate the oocyte so that fertilisation can occur?

Answer 11

Acrosomal enzymes

Question 12

During capacitation, which layer of the oocyte does the sperm bind to?

Answer 12

Zona pellucida

Question 13

TRUE OR FALSE

Fusing of the sperm causes the ovum to become impermeable to other sperm cells.

Answer 13

TRUE

Question 14

What is a conceptus?

Answer 14

A zygote + its associated membranes

Question 15

Which of the following 2 mechanisms are responsible for projecting the conceptus towards the uterus?

a. motility of cilia
b. uterine contractions
c. cervical contractions
d. peristalsis of the uterine tube

Answer 15

A & D

Question 16

What is cleavage during the pre-embryonic period?

Answer 16

Rapid mitotic divisions of the zygote following fertilisation

Question 17

Approximately how long after fertilisation does cleavage occur?

Answer 17

30 hours

Question 18

TRUE OR FALSE

During the process of cleavage, the size of the zygote increases as the number of blastomeres increases.

Answer 18

FALSE

The size of the zygote remains the same

Question 19

Divisions resulting in how many blastomeres occur in the uterine tube?

Answer 19

8

Question 20

How many hours does it take for cleavage to produce 16 blastomeres?

Answer 20

72 hours

Question 21

What are 16 blastomeres collectively known as?

Answer 21

Morula

Question 22

How many cells does there have to be within the conceptus for it to be called a blastocyst?

Answer 22

70-100

Question 23

When a blastocyst starts to form, some of the blastomeres line the inside of the cell. What will these cells differentiate into?

Answer 23

Trophoblasts

Question 24

What is the clump of blastomeres within the blastocyst referred to?

Answer 24

The inner cell mass

Question 25

The evolution of blastomeres within the blastocyst form a….?

a. blastocoel
b. zygote
c. foetus
d. blastocyte

Answer 25

A.

Question 26

Which layer of the conceptus breaks down in order for the blastocyst to be released?

Answer 26

Zona pellucida

Question 27

Where does NORMAL implantation of a conceptus occur?

Answer 27

Uterine wall lining

Question 28

Which cells are responsible for releasing enzymes that allow implantation of the conceptus to occur?

Answer 28

Trophoblasts

Question 29

Name the two cell subtypes that trophoblasts differentiate into after implantation of the conceptus

Answer 29

Cytotrophoblast & syncytiotrophoblast

Question 30

Which trophoblast subtype allows blastocyst implantation by digesting part of the uterine epithelium?

Answer 30

Syncytiotrophoblast

Question 31

Which hormone is produced by the syncytiotrophoblasts?

Answer 31

hCG

Question 32

Explain how the release of hCG by syncytiotrophoblasts helps to maintain the uterine endometrium & the pregnancy

Answer 32

hCG triggers the corpus luteum to produce progesterone which maintains the uterine lining and allows the pregnancy to continue

Question 33

Name the 2 layers of the bilaminar germ disc, formed during week 2 of the pregnancy

Answer 33

Epiblast & hypoblast

Question 34

What is the name of the cavity that starts to form within the inner cell mass of the embryo?

Answer 34

Amniotic sac/cavity

Question 35

Embryoblast is another name for which part of the blastocoel?

Answer 35

The inner cell mass

Question 36

What type of cells surround the amniotic cavity?

Answer 36

Amnioblasts

Question 37

What is the name of the cavity formed by the hypoblast of the bilaminar germ disc?

Answer 37

Primitive yolk sac

Question 38

What is the name of the outermost foetal membrane that develops from the yolk sac?

Answer 38

Chorion

Question 39

What is the name of the process that occurs in week 3 of pregnancy?

Answer 39

Embryogenesis

Question 40

What is the name of the process that transforms the bilaminar germ disc into the trilaminar germ disc?

Answer 40

Gastrulation

Question 41

Name the 3 layers of the trilaminar germ disc

Answer 41

ectoderm, mesoderm & endoderm