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Revision as of 20:28, 25 August 2009
--Mark Hill 21:59, 5 August 2009 (EST) Where are your answers from Laboratory 1 Assessment?
--Emily Wong 13:06, 6 August 2009 (EST) on the discussion page... sorry
--Emily Wong 13:13, 6 August 2009 (EST)
Lab 2 Questions
1. What factor do the synctiotrophoblast cells secrete to support the ongoing pregnancy?
2. What does the corpus luteum secrete to prevent continuation of the menstrual cycle?
3. What are the 2 main tissues to be derived from the germ cell layer continuous with the lining of the amniotic sac?
1. hCG- human chronionic gonadotrophin
2. Progesterone and oestrogen
3. The germ cell layer is the ectoderm and the 2 main tissues derived from this tissue is the nervous system and the epithelial skin surrounding the embryo
--Emily Wong 13:06, 13 August 2009 (EST)
Lab 3 Questions:
1. What period of human development (in weeks) do the 23 Carnegie stages cover?
2. What part of the somite will contribute to the vertebral column?
3. At what Carnegie stage does the human neural tube normally completely close?
1. till day 60 which is the first 8 weeks of human development
2. the sclerotome
3. stage 13
--Emily Wong 13:28, 20 August 2009 (EST)
Lab 4 Questions
1. Into what structure do most blood vessels empty before they enter the embryonic heart?
2. What do the dorsal aortas become in the adult?
3. What are the layers of cells found in a tertiary villi?
1. Sinus Venosus
2. the descending aorta
3. trophoblasts, mesoderm and blood vessels
- Development of the Mouse Embryo
Day 1 Dividing Egg. Cleavage of cells has begun. The Day ends with 4 cells present.
Day 3 Advanced segmentation of the Morula. 16-25 cells within same sized morula.
Day 4 Blastocyst formation
Day 4.5 Implantation and Invasion of the blastocyst into the uterine epithelium
Day 5 Formation of the egg cylinder
Day 6 Differentiation of the egg cylinder
Day 6.5 Gastrulation starts during the period of Advanced Endometrial Reaction
Day 7.5 Neural plate and presomite stage
Day 8 Formation of the first seven somites.
Day 8.5 Rotation of the embryo. The embryo now has between 8 and 12 somites.
Day 9 Formation and closure of the anterior neuropore. There are 13 - 20 somites present in the embryo
Day 9.5 Formation of the posterior neuropore and forelimb bud. There are 21 to 29 somites present and the embryo measures 1.8 - 3.3 mm in length.
Day 10 The posterior neuropore closes and formation of the hind limb bud and tail bud occurs. there are 30 - 34 somites present and the embryo is 3.1 - 3.9mm
Day 10.5 Deep eye lens indentation occurs. There are 35-30 somites present and the embryo is now 3.5-4.9mm.
Day 11 Closure of the lens vesicle. There are 40-44 somites present and the embryo has reached 5-6mm in length.
Day 11.5 The lens vesicle is completely separated from the surface epithelium. There are currently 45 - 47 somites and the embryo reaches a length of 6 - 7mm
Day 12 First signs of fingers. The embryo is 7 - 9mm in length from crown to rump and there are 48 - 51 somites.
Day 13 The anterior footplate becomes indented and the external ear structure is more defined. The embryo is now 9 - 11mm in length and has 52 - 55 somites.
Day 14 The fingers separate. The embryo has 56 - 66 somites and is 11-12mm in length.
Day 15 The toes separate. At this stage the embryo is 12 - 14.4m from crown to rump
Day 16 The umbilical hernia is repositioned. The fetus now measures between 14 and 17 mm.
Day 17 The fingers and toes become joined together. The skin is wrinkled and thickened and the umbilical hernia has disappeared. The fetus measures 16.5 - 20mm depending on the degree of curvature.
Day 18 Whiskers elongate. The length of the embryo varies between 18 and 23 mm due to the degree of curvature of the fetus.
Day 19 The newborn mouse is between 23 and 27mm depending on the degree of flexure of the body axis