Term
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Definition
| The midline cellular code tha forms when mesenchymal cells migrate cranially from the primitive node |
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Term
| Notochordal Process grows cranially between the _______ and _______ until it reaches the _________ |
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Definition
| endoderm and ectoderm; prechordal plate |
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Term
| Transitory neurenteric canal |
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Definition
| Cell of Notohordal process that fuse with the embryonic ectoderm to connect the amniotic cavity with the yolk sac |
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Term
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Definition
| forms when cells from transitory neurenteric canal separate |
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Term
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Definition
| solid rod of cells in the midline between the embryonic ectoderm and endoderm |
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Term
| What 4 things do inductive signals from the notochord do? |
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Definition
| 1) Stimulates a: conversion of overlying surface ectoderm into neural tissue b: the earliest steps in the development of the dorsal pancreas 2) Specify the identity of certain cells within early nervous system 3) Transfom certain mesodermal cells of somites into vertebral bodies. |
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Term
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Definition
| The circular area that is caudal to the primitive streak and covers cloaca |
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Term
| What is extraembryonic mesoderm derived from? |
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Definition
| Cytotrophoblast and sometimes the primitive streak |
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Term
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Definition
| Shallow depression outside cloacal membrane |
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Term
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Definition
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Term
| Describe the migration of the cells from the primitive streak into the cardiogenic area. |
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Definition
| Cells from primitive streak migrate craniallyon each side of the notochordal process around the prechordal plate, where they meet cranially in the cardiogenic area |
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Term
| At what 2 sites does the embryonic disc remain bilaminar? |
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Definition
| The cloacal membrane and oropharyngeal membrane. |
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Term
| Why does the embryonic disc remain bilaminar at specific sites? |
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Definition
| The embryonic ectoderm and endoderm are fused at these sites, thus preventing migration of mesenchymal cells between them |
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Term
| Intraembryonic mesoderm separates th ectoderm and endoderm everywhere except? |
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Definition
| 1) Oropharyngeal membrane cranially 2)Cloacal membrane caudally 3) In the midline cranial to the primitive node, where the notochordal process extends |
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Term
| Where does the notochord extend? |
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Definition
| From the oropharyngeal membrane to the primitive node |
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Term
| When does the notochord degenerate and disappear? |
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Definition
| As the bodies of vertebrae form |
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Term
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Definition
| Notochord that persists inside of each intervertebral disc. |
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Term
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Definition
| tiny, finger-like outpouching or diverticulu from the caudal wall of the yolk sac |
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Term
| What 2 functions does the allantois serve in embryos of reptiles, birds, and some mammals? |
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Definition
| 1) Respiratory function 2) Storage place for urine during embryonic life |
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Term
| Allantois is involved in early ____ ______ |
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Definition
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Term
| Where do blood vessels come from in the allantois? |
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Definition
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Term
| Blood vessels from allantois become what? |
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Definition
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Term
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Definition
| Urinary bladder to umbilicus (belly button) |
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Term
| The urachus in adults is represented as the ____ _____ ________ |
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Definition
| Median umbilical ligament |
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Term
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Definition
| Formation of the neural plate, the neural folds, and their closure to form the neural tube |
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Term
| When is neuralation complete? |
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Definition
| At the end of the 4th week when closure of caudal neuropore occurs |
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Term
| What is the embryonic ectoderm of neural plate called? |
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Definition
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Term
| What happens to the neuroectoderm as the notochord develops? |
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Definition
| It thickens to form the neural plate |
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Term
| What is neural plate formation induced by? |
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Definition
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Term
| What main thing does the neuroectoderm give rise to? |
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Definition
| Central nervous system (consists of brain and spinal cord) |
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Term
| How does the neural plate first appear? |
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Definition
Cranial to the primitive node
Dorsal to the notochordal process and the mesoderm adjacent to it |
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Term
| How far does the neural plate extend as the notochord forms and elongates? |
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Definition
| To the oropharyngeal membrane |
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Term
| What happens to the neural plate on the 18th day? |
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Definition
| It invaginates along its central axis to fom a neural groove (neural folds on each side) |
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Term
| What fuses to form the neural tube? |
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Definition
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Term
| Explain how the surface ectoderm becomes continuous with the back of the embryo? |
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Definition
| The neural tube separates from the surface ectoderm and the fre edges of surface ectoderm fuse |
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Term
| What happens to some neuroectodermal cells as neural folds fuse? |
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Definition
| They lose their epithelial affiniites and attachments to neighboring cells. |
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Term
| What happens to neuroectodermal cels as the neural tube separates from surface ectoderm? |
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Definition
| These neural crest cells migrate ventrolaterally on each side of the neural tube |
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Term
| What is the neural crest? |
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Definition
| An irregular flattened mass between the neural tube and the overlying surface ectoderm |
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Term
| What does neura crest come from? |
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Definition
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Term
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Definition
| region where neural folds haven't fused into a tube; they eventually close (if not, defect happens like spina bifida) |
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Term
| What 5 types of ganglia does the neural crest give rise to? |
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Definition
| 1) dorsal root ganglia 2) sympathetic ganglia 3) enteric ganglia 4) parasympathetic ganglia of CN V11, 1X, X 5) Part of sensory ganglia of cranial nerves |
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Term
| Other than ganglia, what does the neural crest give rise to? |
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Definition
| 1) Schwann cells 2) melanocytes 3) satellite cells of peripheral ganglia 4) cartilage of pharyngeal arches 5) chromafin cell of adrenal medulla 6) pia and arachnoid membranes |
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Term
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Definition
| specialized epidermal cells that join neuralcrest to form sensory ganglia of cranial nerves V V11-X |
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Term
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Definition
| a longitudinal column of intraembryonic mesoderm that forms on each side of the notochord and neural tube |
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Term
| When is the paraxial mesoderm formed? |
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Definition
| As the notochord and neural tube forms |
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Term
| What is the paraxial mesodem continuous with? |
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Definition
| The intermediate mesoderm which gradually things into the lateral mesoderm |
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Term
| What does the intermediate mesoderm produce? |
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Definition
| produce the urinary system and part of the genital system |
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Term
| What is the lateral mesoderm continuous with? |
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Definition
| The extraembryonic mesoderm covering the yolk sac and amnion |
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Term
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Definition
| A series of regular pairs of segments thatare sometimes confused with closely packed mesenchymal cells |
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Term
| What do somitomeres #1-7 do? |
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Definition
| contribute mesoderm to pharyngeal arches; don't form somites |
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Term
| What is head mesenchyme derived from? |
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Definition
| Head mesoderm, ectodermal neural crest and (in the most cranial midline) the prechordal plate |
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Term
| Mesoderm from somitomeres 1-7 give rise to what type of mesenchyme? |
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Definition
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Term
| What happens to the remaining somitomeres (apart from 1-7)? |
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Definition
| condense in a craniocaudal sequence to form 22-44 pairs of somites |
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Term
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Definition
| paired cuboidal bodies that are derived from the paraxial mesoderm |
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Term
| What do somites give rise to? |
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Definition
| Most of the axial skeleton and associated musculature; adjacent dermis of the skin |
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Term
| where are somites located? |
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Definition
| on each side of the developing neural tube |
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Term
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Definition
| dermis and subcutaneous tissue of back |
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Term
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Definition
| muscles of back (epimeric and hypomeric muscles) |
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Term
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Definition
| 1)bones of vertebra 2) cartilage of vertebra |
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Term
| What can somites be used in determining? |
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Definition
| an embryos age by counting them |
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Term
| Where does the intraembryonic coelem first appear? |
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Definition
| lateral mesoderm and the cardiogenic mesoderm |
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Term
| What 2 layers does intraembryonic mesoderm divide lateral mesoderm into? |
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Definition
| 1) somatic (parietal) 2) Splanchic (visceral) |
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Term
| What is somatic (parietal) layer continuous with? |
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Definition
| Extraembryonic mesoderm covering the amnion |
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Term
| What is splanchic (visceral) layer continuous with? |
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Definition
| Extraembryonic mesoderm covering the yolk sac |
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Term
| Somatic (parietal) gives rise to what? |
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Definition
| Inner lining o body wall and parts of the limbs |
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Term
| Splanchic (visceral) gives rise to what? |
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Definition
| Mesothelial covering of visceral organs and part of the wal of the viscera |
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Term
| What do the somatic mesoderm and overlying embryonic ectoderm form? |
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Definition
| Embryonic wall or somatopleure |
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Term
| What does splanchic mesoderm and embryonic ectoderm form? |
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Definition
| Embryonic gut wall or splanchnopleure, or wall of primitive gut |
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Term
| Which body cavities is the intraembryonic coelem divided into during the 2nd month? |
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Definition
| 1) pericardial cavity 2) pleural cavities 3) peritoneal cavity |
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Term
| When do primary chorionic villi began to branch? |
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Definition
| Shortly after they appear at the end of the second week |
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Term
| What grows into primary chorionic villi early in the third week? |
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Definition
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Term
| Secondary chorionic villi |
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Definition
| primary chorionic villi plus the mesenchymal core |
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Term
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Definition
| villi plus mesenchymal core plus blood vessels |
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Term
| What forms the arteriocapillary venous networks? |
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Definition
| Mesenchymal cells that differentiate nto blood capillaries |
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Term
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Definition
| Villi that are attached to the maternal tissue vi the cytotrophoblastic shell |
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Term
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Definition
| Villi that grow from the side of the stem villi |
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