* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download gastrulation - Instructure
Survey
Document related concepts
Vectors in gene therapy wikipedia , lookup
Embryonic stem cell wikipedia , lookup
Polyclonal B cell response wikipedia , lookup
Cell growth wikipedia , lookup
Drosophila melanogaster wikipedia , lookup
Neuronal lineage marker wikipedia , lookup
State switching wikipedia , lookup
Microbial cooperation wikipedia , lookup
Adoptive cell transfer wikipedia , lookup
Cell culture wikipedia , lookup
Somatic cell nuclear transfer wikipedia , lookup
Cellular differentiation wikipedia , lookup
Regeneration in humans wikipedia , lookup
Cell (biology) wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell theory wikipedia , lookup
Transcript
Outline Questions Understanding Gastrulation and Body Folding • Why do developing organisms need multiple cell layers? • What are the three tissue layers created by gastrulation? • How does gastrulation proceed in various vertebrate model organisms (examples: amphibians and birds)? • What is an inducer, and why is this structure so important in development? • What is body folding? – How is a three dimensional structure created? – How does this explain the tubular structure of many organisms? Bio200 Gastrulation and Migration Our Goals: Body Axes and Multiple cell layers • Axis plan – Anterior/posterior – Dorsal/ventral • All tissues come from one of: – Ectoderm – Mesoderm – Endoderm • Gastrulation is the process of creating cell tissue layers Our Goals: Body Axes and Multiple cell layers • Axis plan – Anterior/posterior – Dorsal/ventral • All tissues come from one of: – Ectoderm – Mesoderm – Endoderm • Gastrulation is the process of creating cell tissue layers Ectoderm-derived Nervous system Cornea and lens of eye Epidermis of skin Epithelial lining of: mouth and rectum Mesoderm-derived Skeletal system Circulatory system Lymphatic system Muscular system Excretory system Reproductive system Dermis of skin Lining of body cavity Endoderm-derived Epithelial lining of: digestive tract respiratory tract reproductive tract urinary tract Liver Pancreas Thyroid Parathyroids Thymus Gastrulation is amazing Sea Urchin Gastrulation http://www.youtube.com/watch?v=Lgb4wMsZwZA Fruit Fly Gastrulation http://www.youtube.com/watch?v=j87y7EAj8qE Frog Gastrulation http://www.youtube.com/watch?v=dXpAbezdOho !"#$%&$"'&$()*$)('+,$"'-'.$/0#$$"'&$#($1 • What is the structure at top left? • !"2#('&+3'*'--&*+-+('45-)'7('47#,42'--+6/ Why are *'--& some cells red, blue !"2 #(' &+3' *+-+('4 5-)'colored ('4 #,4 2'--+6/ and yellow? • What do the arrows indicate? Frog Gastrulation Ectoderm Mesoderm Endoderm Blastocoel Dorsal lip Cross section Blastopore Pre-Gastrulation Whole embryo 1. Regions of the frog blastula contain cytoplasmic determinants that determine their fate during gastrulation. Initial Gastrulation Blastopore 2. Formation of the blastopore opening in the embryo. Surface cells move into the interior through the blastopore. Frog Gastrulation Ectoderm Mesoderm Endoderm Presumptive gut Cross section Whole embryo 3. The blastocoel shrinks as the surface cells continue to move inward, forming the three embryonic tissue layers. 4. The three embryonic tissue layers are formed, ready for organogenesis. The blastopore (future anus in frogs) surrounds a plug of yolk cells. http://www.mun.ca/biology/desmid/brian/BIOL3530/DEVO_03/ch03f12.jpg Chicken Gastrulation: Creating the Primitive Streak Top view Side view A Cell migration increases density in the center P Single layer of embryonic cells above a layer of extraembryonic tissue Primitive streak The Henson s node cell group (inducer) forms at one end of the primitive streak If Hensen’s node from a quail embryo is transplanted into a developing chicken embryo, a second embryo begins to develop. What does this experiment imply? Chicken Gastrulation: Inducing Cell movement from A to P Top view Henson s node sends out signal to gastrulate Side view Signaled cells invade into the embryo, creating cell layers Henson s node migrates posteriorly… Inducer: Cells that signal gastrulation • A group of cells in developing embryos that release the necessary signals for gastrulation • This function is – transferrable – At least partially conserved between related species Inducer: Cells that signal gastrulation • A group of cells in developing embryos that release the necessary signals for gastrulation • This function is – transferrable – At least partially conserved between related species Body folding: Creating basic embryo morphology • As development proceeds, the body shape folds anteriorly then posteriorly • The embryo gradually loses most contact points with yolk Top view Side view Body folding: Creating basic embryo morphology • As development proceeds, the body shape folds anteriorly then posteriorly • The embryo gradually loses most contact points with yolk • Sustained by vasculature (blood vessels) • Apoptosis links endoderm to outside in front and back This creates the digestive tract • Top view Side view Gastrulation through Neurulation http://www.youtube.com/watch?v=D76B0K-D4rY Key Concepts • Gastrulation is the process of creating three cell layers – These cell layers are ectoderm, mesoderm, and endoderm – Each cell layer is destined for a set of tissues in the body • Gastrulation requires coordinated cell movements, signaling, differentiation and proliferation to create cell layers. – Inducers are key signaling cells that influence surrounding tissues to initiate tissue formation. – Different organisms have different patterns of gastrulation typified by particular cell movements. • Body folding creates a three dimensional shape from a flat sheet of cells using cell movements and sometimes apoptosis to arrive at a final shape.