Lecture 19- Maternal Recognition of Pregnancy

Question 1

Conceptus

Answer 1

embryo and developing placental cells

Question 2

early embryonic development

Answer 2

ootid –> syngamy –> zygote –> cell division –> morula –> differentiation –> early blastocyst –> hatching blastocyst –> hatched blastocyst

Question 3

Hatching process (blasocyte)

Answer 3

1. blastocyst growth and fluid accumulation
2. production of enzymes by the trophoblast
3. contraction of the blastocyst

Question 4

Embryonic Genome Activation (maternal to embryonic Transition )

Answer 4

• degradation of maternal RNA and protein accumulated in ooplasm during oogenesis
• embryo takes ‘ownership’ of gene expression and cell biology of blastomeres

Question 5

when does embryonic genome activation happen (by species)

Answer 5

ruminants- 8-16 cell transition

swine - 4 cell stage

human - 4 cell stage

mice - 2 cell stage

Question 6

Maternal Recognition of Pregnancy

Answer 6

developing conceptus signals its presence to prevent luteolysis and to assure maintenance of the corpus lute and sustained secretion of progesterone beyond the normal cyclical activity

Question 7

Bovine conceptus signalling

Answer 7

secrets interferon tau
INFt blocks up regulation of oxytocin receptors in the endometrium at late diestrus –> no pulsatile secretion of PGF2alpha by the endometrium –> maintenance of CL and progesterone secretion

Question 8

Histotroph

Answer 8

amino acids
proteins
saccharides
growth factors
lipids
minerals
ions
vitamins

Question 9

Elongation of Preimplantation Conceptus

Answer 9

ovoid, tubular or filamentous 
accumulation of elongation drivers in the uterine lumen causes changes in trophectoderm biology 
- cellulose reprogramming 
- rapid proliferation 
- cytoskeleton modification 
- cellular migration