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 13:47, 15 May 2017

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 GA week 9.

Stage 18
Stage 18 - Right Lateral

Stage18 bf11.jpg

 ‎‎Mobile | Desktop | Original

Stage 18 | Embryo Slides
Stage 18 - Left Lateral

Stage18 bf12.jpg

 ‎‎Mobile | Desktop | Original

Stage 18 | Embryo Slides


Stage 18
Stage 19 - Left Lateral

Stage19 bf2.jpg

 ‎‎Mobile | Desktop | Original

Stage 19 | Embryo Slides
Stage 19 - Right Lateral

Stage19bf13-icon.jpg

 ‎‎Mobile | Desktop | Original

Stage 19 | Embryo Slides

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 continues.

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.

Neural

Neural System Development duramater appears [1]


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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.

Timeline

Week 7 - Human Embryo Stages and Events (GA week 9) 
Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9
Day
Stage
Event
43
{{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

44
Stage 18 Stage18 bf1c.jpg

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]

neural duramater appears[1]

45
   

liver (stage 18 to 23) biliary ductules developed in periportal connective tissue produces ductal plates that receive biliary capillaries[3]

46
   
47
   
48
Stage 19 Stage19 bf1c.jpg Neural System Development accessory olivary nucleus appears[4]
49
   
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
  1. 1.0 1.1 <pubmed>15478101</pubmed> Cite error: Invalid <ref> tag; name 'PMID15478101' defined multiple times with different content
  2. Müller F & O'Rahilly R. (2004). Olfactory structures in staged human embryos. Cells Tissues Organs (Print) , 178, 93-116. PMID: 15604533 DOI.
  3. 3.0 3.1 Godlewski G, Gaubert-Cristol R, Rouy S & Prudhomme M. (1997). Liver development in the rat and in man during the embryonic period (Carnegie stages 11-23). Microsc. Res. Tech. , 39, 314-27. PMID: 9407542 <314::AID-JEMT2>3.0.CO;2-H DOI.
  4. Müller F & O'Rahilly R. (1990). The human brain at stages 18-20, including the choroid plexuses and the amygdaloid and septal nuclei. Anat. Embryol. , 182, 285-306. PMID: 2268071


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