DEVELOPMENT Session 15

Question 1

During the second week , what happens during implantation ?

Answer 1

• The chorion secretes enzymes to digest away some of the tissue
• it also secretes HCG

Question 2

At the end of the second week gastrulation occurs , what is gastrulation ?

Answer 2

• The inner cell mass becomes the embryonic disk

Question 3

What is the first organ to appear ?

Answer 3

• The nervous system

Question 4

What occurs around the embryo in third week ?

Answer 4

• A thickening appears along the length of the embryo
• Then the centres begins to fold inward , forming a pocky and neural folds
• Next , the neural tube forms which later develops into the brain and the spinal cord

Question 5

In the fourth and fifth week , what connects the developing embryo to the placenta ?

Answer 5

• Umbilical cord

Question 6

during the fourth and fifth week what development occurs to the limbs and head ?

Answer 6

• limb buds appear which later develop into arms and legs
• during fifth week , the head enlarges and it is possible to make out the developing eyes , ears and nose

Question 7

in which week does the end of organogenesis happen ?

Answer 7

• during week 6 through 8

Question 8

What 5 adaptive features is the fetal circulation based on ?

Answer 8

• the umbilical vein
• the ductus venosus
• The foramen ovale
• The ductus arteriosus
• two umbilical arteries