BGDA Practical 7 - Week 7: Difference between revisions

From Embryology
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===Limb Development===
===Limb Development===
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* Digits - hand and foot "paddles", death (apoptosis) of cells between digits commences.
* Digits - hand and foot "paddles", death (apoptosis) of cells between digits commences.
| [[File:Mouse_interdigit_apoptosis_01.jpg|300px]]
[[File:Mouse_interdigit_apoptosis_01.jpg|200px]]
|}
 
* Ossification - bones form by [[E#endochondral ossification|endochondral ossification]] and throughout embryo replacement of cartilage with bone (week 5 onward).
* Ossification - bones form by [[E#endochondral ossification|endochondral ossification]] and throughout embryo replacement of cartilage with bone (week 5 onward).
** mesenchyme condensation -> cartilage development -> cartilage death -> vascularisation -> bone development (primary ossification)


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<gallery>

Revision as of 11:01, 19 May 2014

Introduction

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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 week 9 (GA week 9).

(Place 7 week ultrasounds here)

Endocrine Development

Pancreas Development Week 7 to 20 pancreatic hormones secretion increases, small amount maternal insulin.

Thyng1914 fig02.jpg Stage22 pancreas a.jpg
Week 7 Week 8

Musculoskeletal Development

Musculoskeletal System Development

Limb Development

  • Digits - hand and foot "paddles", death (apoptosis) of cells between digits commences.

Mouse interdigit apoptosis 01.jpg

  • 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.


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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.


Detailed Week by Week

The following information is a detailed timeline of embryonic development between week 3 to 8 and content does not form part of the current practical class.

Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8

Embryo Stages and Events

Day Stage Event
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Endocrine - Pancreas Development Week 7 to 20 pancreatic hormones secretion increases, small amount maternal insulin

Respiratory System Development Week 7 - enlargement of liver stops descent of heart and lungs

44
Stage 18 Stage18 bf1.jpg

Limb Bone form by endochondrial ossification and throughout embryo replacement of cartilage with bone (week 5-12).

Smell vomeronasal fibres and nervus terminalis PMID 15604533

Liver obturation due to epithelial proliferation, bile ducts became reorganized, continuity between liver cells and gut PMID 9407542

Neural System Development duramater appears PMID 15478101

45
   

Liver (stage 18 to 23) biliary ductules developed in periportal connective tissue produces ductal plates that receive biliary capillaries PMID 9407542

46
   
47
   
48
Stage 19 Stage19 bf1.jpg Neural System Development accessory olivary nucleus appears PMID 2268071
49
   


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


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Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8