Human pregnancy: landmarks and pathologies

Question 1

Describe steps in implantation

Answer 1

1. Apposition between the outer trophectoderm layer of embryo and uterine epithelium which should become adhesion
   
   2. Trophectoderm cells ten proliferate and differentiate into cytotrophoblast
      
      • Invade the maternal decidualising endometrium
   3. The invading cytotrophoblast cells anchor the embryo into uterine decidua
   4. In parallel with invasion of cytotrophoblast, Decidua grows over the blastocyst until it completely buried in maternal tissue
      
      • Completes implantation process
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Question 2

Describe the pattern of human embryo development

Answer 2

• Main tissues develop during first 8 weeks
  
  • structural and functional development are generally focused in the first and second halves of pregnancy respectively, although there may be some overlap
  • the brain, lungs and digestive system show a different pattern, in that development starts early in pregnancy, and then continues throughout pregnancy
  • the later stages of pregnancy show accelerated development, as these tissues are key to life after delivery - the brain must control all the relevant systems, the lungs must absorb oxygen from the air, and the gut must absorb nutrients

Question 3

what is parturition

Answer 3

process that occurs at the end of pregnancy

Question 4

Describe process of parturition

Answer 4

b. Lasts the longest as cervix changes from rigid structure to a pliable tissue allowing passage of baby
- Myometrium changes substantially during first stage of labour
- From muscular tissue that as relaxed to permit expansion of uterus to tissue showing powerful coordinated contractions that propel the infant through cervix, vagina

Question 5

What complications may arise in pregnancy

Answer 5

early pregnancy loss, miscarriage, pre-eclampsia, pre-term labour, maternal bleeding

Question 6

how is pre-eclampsia diagnosed

Answer 6

with high blood pressure of 140/90 and presence of protein in urine

Question 7

Effect of pre-eclampsia effects

Answer 7

decreased growth in uterus

Question 8

causes of pre-term labour

Answer 8

infections in the uterus and result of pre-eclampsia

Question 9

causes of maternal bleeding

Answer 9

uterus infection and uncontrolled bleeding

Question 10

Ethical reasons for studying human pregnancy

Answer 10

may cause harm to mother or infant. If only study on some tissues, only limited information studied on progression of normal pregnancy

Question 11

What are the limitations of using model for studying human pregnancy

Answer 11

difficult to extrapolate from one species to another

time frames of pregnancy are very different and malfunctions do not resemble those in human