Physiology 3120 Lecture Notes - Lecture 68: Organogenesis, Human Chorionic Gonadotropin, Endometrium
15 May 2018
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Lecture 68 – Pregnancy and Fetal Development
Implantation of blastocyst
- Syncytiotrophoblasts digest endometrium + hCG and P4
- Cytotrophoblasts: mitotic
- Organogenesis is initiated
- Moving form bilaminar (two cells) to trilaminar separation
- Epiblasts: become the fetus
- Hypoblasts: vessels for pregnancy
- LOOK AT TIME:
o Implantation occurs at day 6 and have bilaminar
o Trilayer forms later
o WEEK 3: differentiation of cell types of the ectoderm, mesoderm and endoderm
occurs = beginning of organogenesis
o Week 3 = cell layers start to form
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- Cells to make our sex (gonads) come from the mesoderm
- Different organs arise from the ecto, meso and endoderm
- THERE ARE THREE LAYERS
- Endo: inside
- Ecto: outside
- Meso: in the middle
Week 4 onwards – embryo and fetus
- In week 4 the organ systems start to develop
- Differentiation occurs and cell types start to establish their final lineage as we move into
organ development
- This occurs up to week 8 (all external and internal structures start to form)
- Week 8 is the end of the embryonic stage
- From week 8 as we move to 32-40 weeks, there is a growth/fetal phase
- Form has been established between week 3-8 and from week 8- term there is the fetal stage
which is associated with growth
- There is still the differentiation of some cell types but the majority have been formed before
week 8
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Moving form bilaminar (two cells) to trilaminar separation. Implantation occurs at day 6 and have bilaminar: trilayer forms later, week 3: differentiation of cell types of the ectoderm, mesoderm and endoderm occurs = beginning of organogenesis, week 3 = cell layers start to form. Cells to make our sex (gonads) come from the mesoderm. Different organs arise from the ecto, meso and endoderm. In week 4 the organ systems start to develop. Differentiation occurs and cell types start to establish their final lineage as we move into organ development. This occurs up to week 8 (all external and internal structures start to form) Week 8 is the end of the embryonic stage. From week 8 as we move to 32-40 weeks, there is a growth/fetal phase. Form has been established between week 3-8 and from week 8- term there is the fetal stage which is associated with growth.
