Anatomy Flashcards
What is gestation?
The time required for full development of a foetus in utero
Which period of pregnancy is known as the ‘pre-embryonic period’?
The first 2 weeks of prenatal development (first 2 weeks of pregnancy)
Which period of pregnancy is known as the ‘embryonic period’?
3-8 weeks
How far into gestation does the embryo become the foetus?
After 9 weeks up until birth
Name the 6 events that occur during the pre-embryonic period
- Fertilisation
- Cleavage
- Formation of Blastocyst
- Implantation
- Formation of Germ Disc
- Formation of Embryonic Membranes
During fertilisation, the reproductive tract delivers the sperm to which part of the uterine tube?
a. Egg
b. Follicle
c. Ampulla
d. Ovary
C. Ampulla
How long after ovulation do the egg and sperm meet?
12-24 hours
How long is an oocyte viable for? How long is a sperm viable for?
Oocyte - 1 day; Sperm - 3 days
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
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
How long does sperm capacitation take?
6-8 hours
Which molecules, released by the sperm, allow it to penetrate the oocyte so that fertilisation can occur?
Acrosomal enzymes
During capacitation, which layer of the oocyte does the sperm bind to?
Zona pellucida
TRUE OR FALSE
Fusing of the sperm causes the ovum to become impermeable to other sperm cells.
TRUE
What is a conceptus?
A zygote + its associated membranes
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
A & D
What is cleavage during the pre-embryonic period?
Rapid mitotic divisions of the zygote following fertilisation
Approximately how long after fertilisation does cleavage occur?
30 hours
TRUE OR FALSE
During the process of cleavage, the size of the zygote increases as the number of blastomeres increases.
FALSE
The size of the zygote remains the same
Divisions resulting in how many blastomeres occur in the uterine tube?
8
How many hours does it take for cleavage to produce 16 blastomeres?
72 hours
What are 16 blastomeres collectively known as?
Morula
How many cells does there have to be within the conceptus for it to be called a blastocyst?
70-100
When a blastocyst starts to form, some of the blastomeres line the inside of the cell. What will these cells differentiate into?
Trophoblasts
What is the clump of blastomeres within the blastocyst referred to?
The inner cell mass
