Conception, Embryology, Preconception Care

Question 1

Sequence of events for formation of baby

Answer 1

Genome: full complement of DNA and chromosomes
Genes: homeobox and regulatory genes
Pattern formation: cell specialisation and right organ in right place.

Question 2

What happens following 5 days of ovulation and fertilisation.

Answer 2

1. Zygote fertilised
2. Early cleavage (4 cell stage)
3. Morula (totipotent can become any cell)
4. Early blastocyst inner mass is pluripotent can become range of cells not all and outer cells form placenta.
5. Late blastocyst implants

Question 3

What is the embryonic disc?

Answer 3

It is the parts of the embryo that will develop into body structures
Ectoderm outer layer: becomes NS and skin
Mesoderm: muscle, skeleton, kidney and reproductive system
Endoderm inner layer: encode rinse glands, lungs, digestive tract, liver.

Forms around 2 weeks of fertilisation

Question 4

What is the function of the placenta? (SERPENT)

Answer 4

Storage- stores glycogen, iron, fat, soluble vitamins
Endocrine- produces steroid and placental proteins eg hCG or PAPP-A/ PAPP-B
Respiration- O2 and CO2 transferred from maternal circulation to fetus via diffusion
Protection- filter most bacteria prevents virus transfer
Excretion- CO2 and bilirubin is excreted to allow new RBS
Nutrition- receives raw material for growth and development protein, fats, carbohydrate, water
Transfer of substances- lipid, water, glucose, ions, endocytosis of macromolecules.

Question 5

What does the placenta look like?

Answer 5

Attached to decidua basalts in pregnancy it’s a dark red colour the fetal surface is greyish blue

Chorion: outer membrane rough thick produces enzymes reducing progesterone and hormones eg oxytocin
Amnion- inner membrane moves over chorion aided by mucous contains amniotic fluid