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22 Cards in this Set
- Front
- Back
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Angiogenesis requires |
flipping of apical basal polarity and induction of endothelial cell
modulation of cell-cell contacts local matrix degredation |
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VEGF acts first on new capillaries |
loosens cell-cell contact so they can migrate Newly formed endothelial cells form new vessels by splitting a vessel in two and sprouting |
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TGFbeta and PDGF (platelet derived growth factor) |
stabilize network and recruit pericyte cells |
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Some vessels can sprout, others fail |
balance between VEGF and factors that promote endothelial inactivity (tight pericyte contact, ECM molecules, VEGF factors) VEGF guides sprouts PDGF b promotes reqruitment of PCs to sprouts |
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Sprout tip contact |
adhesive or repulsive reactions Fusion of vacuoles EC-EC surface, these need to be maintained to prevent leaks, continuous lumen Blood flow, O2 delivery, stabilization of junctions, matrix deposition, and tight PC attachment increase |
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Precursors of arteries Precursors of veins No ephrinB |
have ephrin B2 expressed have ephrin B2 receptors Vasculogenesis occurs but angiogenesis cant |
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EphB4 and ephrin B2 ensure |
that arteries only interact and fuse with veins proper fusing in non border areas |
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Sites of ephrin and eph |
1. arterial-venous: maintain directivity by insuring that EC dont intermingle 2. endothelial-endothelial interations: communication between cells 3. endothelial-mesenchimal interactions: patterning of the vasculature |
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Blood vessel specification |
Angioblasts- specified, will form arteries or veins Shh induces VEGF - notch- gridlock - ephrin Arteries first - more VEGF - more gridlock - ephrin B2 Veins next - less notch - less gridlock - ephB4 |
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Arteries align with |
nerves |
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Red blood cells Steady state Hematopoiesis stem cell |
killed in spleen and replaced from stem cells Blood cells, intestinal crypt, epidermal, spermatocytes is HSC - hematopeotic stem cell |
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Hematopoesis two phases |
primitive and definitive differ in sites of blood cell production, timing, morphology of cells and types of globin genes two types of hemopoetic stem cells |
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primitive phase |
yolk sack derived stem cells produce RBCs early, everything except lymphocytes origionate from lateral mesoderm surrounding aorta - aorta gonad mesonephros (AGM) |
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definitive phase |
splanchnopleur produce definitive hematopoeitic stem cell - pluripotent RARE - dependent on SCL transcription factor -binds to osteoblasts - keeps them pluipotent, attacts HSC, and prevents apoptosis |
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paracrine factors derive differention of HSC |
Cytokines are involved in blood cell and lymphocyte production Hemopoetic inductive microenvronments (HIM) - development is determined by which cytokines niches HSC interacts with |
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Niches provied |
physical support, soluble factors, cell mediated interactions to maintain and regulate HSC, aid in stem cell renewal and differentiation |
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Endoderm functions |
1. induction of mesodermal germ layer
2. lining digestive tube and respiratory tube |
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Human digestive system |
gut folds forming for and hindgut ectodermal entrence at both ends of the gut tube oral end is blocked by oral plate or stomodeum this breaks |
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brain ectoderm and stomodeum ectoderm interact |
oral ectoderm forms rathkes pouch and becomes glandular part of pituitary neural tissue forms infundibulum which becomes neural part of pituitary |
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digestive tube |
endodermal - lining smooth muscle surrounding is from the lateral plate mesoderm pharynx, esophagus, stomach, small, large intestines develop and yolk sac connection is severed endoderm meets ectoderm at cloacal membrane - ruptures to form anus |
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Differentiation of gut organs is based on |
mesodermal mesenchyme signals different structures in different regions specification happens before tube forms RA FGF gradients remain through development with flexible boundaries similar in chick frog and zebrafish |
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Wnt and BMP in gut |
wnt in posterior, bmp and wnt inhibitors in anterior (thymus, pancreas, stomach, liver) |
