Early human development

What does embryogenesis achieve?

patterning, major axis defined, three germ layers defined, rudiments of the major organs

What does gastrulation generate?

three germ layers

What are the three germ layers?

ectoderm, mesoderm, endoderm

What does the ectoderm layer mean?

outside

What does mesoderm layer mean?

everything between

What does endoderm layer mean?

inside

What happens in fertilisation? (first step)

sperm enters oocyte, meiosis II completed

What is the path of a sperm cell?

corona radiata, zona pellucida, plasma membrane of secondary oocyte, cytoplasm of secondary oocyte

What is cleavage?

a rapid form of cell division that does not allow cell growth

Do the cells increase in mass in cleavage?

no because no time

What steps does cleavage undergo?

zygote, 2 cells, 4 cells, morula, blastocyst

What are the structures in the blastocyst?

embryoblast (inner cell mass), blastocyst cavity, trophoblast

What does the trophoblast do?

form placenta

What cells are required to form the placenta?

cytotrophoblast cells

When does fertilisation happen?

within the uterine tube 12-24 hours after fertilization

When does cleavage happen?

30 hours after fertilization

When does morula happen?

3-4 days after fertilization

When does the blastocyst happen/form?

4.5-5 days after fertilization

When does implantation happen?

6 days after fertilization

What do stem cells do?

replace themselves and generate differentiated daughter cells

Why do we need stem cells?

growth, renewal, repair

What is the clinical utility of stem cells?

long lasting skin grafts (gene edited)

What happens after cleavage?

blastula formation/implantation

What happens after gastrulation?

organogenesis

What does CRISPR/Cas9 do?

creates target dsDNA cuts in genone, cell repairs the break, very versatile

Step 1 for CRISPR/Cas 9 gene therapy strategy for epidermolysis bullosa (EB)

isolate skin cells from patient biopsy

Step 2 for CRISPR/Cas 9 gene therapy strategy for epidermolysis bullosa (EB)

use CRISPR/Cas 9 to correct mutation in skin cells (fibroblasts and keratinocytes)

Step 3 for CRISPR/Cas 9 gene therapy strategy for epidermolysis bullosa (EB)

genomic, mRNA, protein analysis

Step 4 for CRISPR/Cas 9 gene therapy strategy for epidermolysis bullosa (EB)

grow gene corrected skin using novel skin engineering method

Step 5 for CRISPR/Cas 9 gene therapy strategy for epidermolysis bullosa (EB)

graft skin onto patient wounds

What do unipotent stem cells in the skin allow?

constant renewal

What is the stem cell hierarchy?

totipotent cell, pluripotent cell, multipotent cell, unipotent cell

What is a totipotent cell?

capable of giving rise to all cell types of body and extra-embryonic tissues

What is a pluripotent cell?

capable of giving rise to all cell types of the body

What is a multipotent cell?

capable of giving rise to all cell types of a particular tissue or organ

What is a unipotent cell?

not capable of giving rise to other cell types

What type of cell is this

totipotent

What type of cell is this

pluripotent

What type of cell is this?

multipotent

What type of cell is this?

unipotent

What is required to form placenta?

cytotrophoblast cells