Pregnancy, Growth, Development And Genetics

Question 1

When does the prenatal period begin and end?

Answer 1

Begins at fertilisation, ends at birth

Question 2

When does the Postnatal period begin and end?

Answer 2

Begins at birth, ends at death

Question 3

Define: 
Ovum, 
Zygote,
Embryo,
Foetus

Answer 3

Ovum- from ovulation to fertilisation
Zygote- from fertilisation to implantation
Embryo- from implantation to 8th week of pregnancy
Foetus- 8+ weeks

Question 4

Define fertilisation. Where does fertilisation usually take place?

Answer 4

Fertilisation is the meeting of the secondary oocyte and the sperm cell. It typically within the uterine tubes.

Question 5

How is the body prepared for the transportation of sex cells?

Answer 5

Sperm cells contain large amount of mitochondria and prostaglandins which stimulate the tail to swim and give the cell energy. Prostaglandins also cause muscular contractions of the uterus and uterine tubes to help push the sperm cells forward

Question 6

What does fertilisation result in?

Answer 6

A diploid zygote containing 23 pairs of chromosomes

Question 7

What is the name of the protein which the sperm uses to erode away the corona radiata of the egg cell?

Answer 7

Acrosome

Question 8

When does the 1st, 2nd and 3rd trimester occur during pregnancy?

Answer 8

1st trimester- weeks 1-12
2nd trimester- weeks 13-27
3rd trimester- weeks 28+

Question 9

Following fertilisation, the cells undergo a period of mitosis where they divide to become increasingly smaller. What is this period called?

Answer 9

The period of cleavage

Question 10

How long does it take for the dividing mass of cells to move down the uterine tube and into the uterus?

Answer 10

On average, 3 days

Question 11

At the end of the first week following fertilisation, the mass of cells implants into the lining of the endometrium. At this point, what is the mass of cells called? What is the uterus lining called?

Answer 11

Mass of cells is called the blastocyst

Uterus endometrium is called the decidua

Question 12

What does the blastocyst become?

Answer 12

The embryo (embryoblast) and the placenta

Question 13

What is the outer layer of the blastocyst called?

Answer 13

The trophoblast

Question 14

Which hormone does the trophoblast secrete to maintain pregnancy? This hormone is also the basis of pregnancy testing.

Answer 14

HCG- human chorionic gonadotrophin

Question 15

Which four primary hormones does the placenta secrete? What are the roles of these hormones?

Answer 15

Placental lactogen- stimulates breast development
Estrogen and progesterone- maintain uterine lining, inhibit secretion of LH and FSH, stimulate development of mammary glands
Relaxin- relaxes the pelvis

Question 16

When does the neural tube form and what does it become? Which process forms the neural tube?

Answer 16

The tube forms during the 4th week of pregnancy and develops into the spinal cord and brain. Neurulation forms the neural tube.

Question 17

What occurs during gastrulation?

Answer 17

The inner cell mass becomes the 3 layer (ectoderm, endoderm and mesoderm) building blocks for the embryo

Question 18

What does the ectoderm become?

Answer 18

The nervous system and sensory organs

Question 19

What does the mesoderm become?

Answer 19

Muscle and bone tissue, blood, vessels, reproductive organs and kidneys.

Question 20

What does the endoderm become?

Answer 20

The epithelial linings of the digestive tract, respiratory tract, urinary bladder and urethra.

Question 21

Name the 5 roles of the placenta.

Answer 21

To obtain nutrients and oxygen for the foetus
To dispose of fetal waste products (e.g. CO2, urea, bilirubin)
To produce hormones (HCG)
Immunological role
Protects and nurtures the foetus

Question 22

What are the names of the two membranes surrounding the foetus?

Answer 22

The chorion (closest to mum) and the amnion (closest to baby)

Question 23

Give six functions of amniotic fluid

Answer 23

• barrier to infection
• prevents amnion from sticking to the foetus
• provides a constant environmental temperature
• allows the foetus to move freely
• cushions against knocks and bumps
• allows for symmetrical growth of the foetus

Question 24

What is the medical term given for too much amniotic fluid?

What about too little?

Answer 24

Polyhydramnios- too much

Oligohydramnios- too little

Question 25

What is a ‘normal’ amount of amniotic fluid?

Answer 25

Between 1000 and 1500 ml

Question 26

What is the name of the jelly which surrounds the umbilical cord?

Answer 26

Whartons jelly