BGDA Practical 7 - Week 7: Difference between revisions
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* '''intramembranous ossification''' - The term used to describe the process of replacement of a membranous mesenchyme with bone by osteoblasts (bone-forming cells). Mesenchymal cells (osteoprogenitor cells) differentiate into osteoblasts at the initial sites of ossification (ossification centre). Occurs in skull (jaw, cranial vault) and clavicle. The majority of the skeleton is formed by an alternative process of bone formation on a cartilaginous template, endochondral ossification. | * '''intramembranous ossification''' - The term used to describe the process of replacement of a membranous mesenchyme with bone by osteoblasts (bone-forming cells). Mesenchymal cells (osteoprogenitor cells) differentiate into osteoblasts at the initial sites of ossification (ossification centre). Occurs in skull (jaw, cranial vault) and clavicle. The majority of the skeleton is formed by an alternative process of bone formation on a cartilaginous template, endochondral ossification. | ||
==Neural== | |||
[[Neural System Development]] duramater appears <ref name=PMID15478101><pubmed>15478101</pubmed></ref> | |||
Revision as of 12:47, 15 May 2017
Introduction
Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 |
Key Events of Human Development during the seventh week (week 7) following fertilization or clinical GA week 9.
Stage 18 | |||||||
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Stage 18 | |||||||
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Endocrine Development
Pancreas Development Week 7 to 20 pancreatic hormones secretion increases, small amount maternal insulin.
Week 7 | Week 8 |
Musculoskeletal Development
Musculoskeletal System Development
Limb Development
- Digits - hand and foot "paddles", death (apoptosis) of cells between digits continues.
- Ossification - bones form by endochondral ossification and throughout embryo replacement of cartilage with bone (week 5 onward).
- mesenchyme condensation -> cartilage development -> cartilage death -> vascularisation -> bone development (primary ossification)
- endochondral ossification - (Greek, endon = within) The developmental term used to describe the process of the replacement of the embryonic body skeleton "template" formed by cartilage with bone. The osteoblasts are the bone-forming cells. The other bone formation process is intramembranous ossification.
- intramembranous ossification - The term used to describe the process of replacement of a membranous mesenchyme with bone by osteoblasts (bone-forming cells). Mesenchymal cells (osteoprogenitor cells) differentiate into osteoblasts at the initial sites of ossification (ossification centre). Occurs in skull (jaw, cranial vault) and clavicle. The majority of the skeleton is formed by an alternative process of bone formation on a cartilaginous template, endochondral ossification.
Neural
Neural System Development duramater appears [1]
Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 |
Additional Information
Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page. |
Timeline
Week 7 - Human Embryo Stages and Events (GA week 9) | ||
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Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9 | ||
Event | ||
{{Pancreas{{ Week 7 to 20 pancreatic hormones secretion increases, small amount maternal insulin
respiratory Week 7 - enlargement of liver stops descent of heart and lungs | ||
Stage 18 |
limb bone form by endochondrial ossification and throughout embryo replacement of cartilage with bone (week 5-12). smell vomeronasal fibres and nervus terminalis[2] liver obturation due to epithelial proliferation, bile ducts became reorganized, continuity between liver cells and gut[3] | |
liver (stage 18 to 23) biliary ductules developed in periportal connective tissue produces ductal plates that receive biliary capillaries[3] | ||
Stage 19 | Neural System Development accessory olivary nucleus appears[4] | |
Note - the day timing of stages is only approximate, system names link to first page of that specific system, and events are based upon the literature cited below. | ||
References
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See also the 1914 Historic description of a 17.8 mm Human Embryo that from external appearance is approximately a Stage 19 human embryo. 1914 Human Embryo 17.8 mm Harvard Collection
Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 |