BGDA Practical 7 - Week 5: Difference between revisions

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==Introduction==
==Introduction==
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Key Events of Human Development during the fifth week (week 5) following fertilization or Clinical week 7 (LMP).
Key Events of Human Development during the fifth week (week 5) following fertilization or clinical {{GA}} week 7.


By this week there are many different organs and tissues differentiating throughout the embryo, only a few select systems will be discussed.
By this week there are many different organs and tissues differentiating throughout the embryo, only a few select systems will be discussed.
[[File:Stage15 sagittal section upper half 01.jpg|thumb|Later week 5 development ([[Carnegie_stage_15|Stage 15]]) showing a sagittal section upper half of human embryo.]]


{{SlideStage15bf2}}
===Cardiovascular===
===Cardiovascular===
* Heart - [[S#septation|septation]] starts, [[A#atrial septation|atrial septation]] and [[V#ventricular septation|ventricular septation]]
* Heart - [[S#septation|septation]] starts, [[A#atrial septation|atrial septation]] and [[V#ventricular septation|ventricular septation]]
* Vascular - 3 vascular systems (systemic, placental, [[V#vitelline|vitelline]]) extensively remodelled
* Vascular - 3 vascular systems (systemic, placental, [[V#vitelline|vitelline]]) extensively remodelled


{| border='0px'
|-
| [[File:Heart1_looping icon.jpg|90px|link=Heart Looping Movie]]
| [[File:Heart1_realign icon.jpg|90px|link=Heart Realign Movie]]
| [[File:Heart1_atrium icon.jpg|90px|link=Heart Atrial Septation Movie]]
| [[File:heart1 ventricle icon.jpg|90px|link=Heart Outflow Septation Movie]]
|-
| [[Heart Looping Movie|Heart Looping]]
| [[Heart Realign Movie|Heart Realign]]
| [[Heart Realign Movie|Heart Atrial Septation]]
| [[Heart Realign Movie|Heart Outflow Septation]]
|-
|}
See also Heart Development Timeline - [[Basic Cardiac Embryology]]
See also Heart Development Timeline - [[Basic Cardiac Embryology]]
===Respiratory===
===Respiratory===
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Heart Development Timeline (see [[Basic Cardiac Embryology]])
Heart Development Timeline (see [[Basic Cardiac Embryology]])
{|
| valign=bottom|{{Cardiovascular stage 13 movie}}
|
{{CVS cartoons}}
|}


[[File:Stage13-CVS-icon.jpg|200px|link=Movie_-_Cardiovascular_3D_stage_13]]
===Atrial Septation===
[[File:Stage_13_image_067.jpg|600px]]
[[File:Stage_13_image_068.jpg|600px]]


==Respiratory==
==Respiratory==
[[File:Stage14_respiratory_tract.jpg|thumb|Respiratory Tract (stage 13)]]
 
{|
{|
|-
|-
| [[File:Stage13-GIT-icon.jpg|200px|link=Movie_-_Gastrointestinal_Tract_3D_stage_13]]
| {{Gastrointestinal stage 13 movie}}
| '''Week 4''' - [[L#laryngotracheal groove|laryngotracheal groove]] forms on floor foregut.
| '''Week 4''' - [[L#laryngotracheal groove|laryngotracheal groove]] forms on floor foregut.


Line 65: Line 59:
|}
|}


==Neural==
The trachea can be see making its initial branching into the lung bud mesenchyme.
[[File:Embryo_stage13-_brain_flexures.jpg|thumb|Neural tube - brain flexures (stage 13)]]
[[File:CNS secondary vesicles.jpg|thumb|Neural - 5 secondary vesicles]]


{|
{|
| [[File:Stage 13 image 070.jpg|600px]]
| [[File:Gray0961.jpg|300px]]
|-
|-
| [[File:Stage13-CNS-icon.jpg|200px|link=Movie_-_Central_Nervous_System_3D_stage_13]]
| Bifurcation of the trachea into the main or primary bronchi, the left and right bronchus.
| Rapid growth folds the neural tube forming 3 brain flexures:
| Adult bronchial tree.
# [[C#cranial flexure|cranial flexure]] (cephalic)- pushes mesencephalon upwards
# [[P#pontine flexure|pontine flexure]] - generates 4th ventricle
# [[C#cervical flexure|cervical flexure]] - between brain stem and spinal cord
 
|}
|}


==Neural==
During week 5 the five secondary brain vesicles form from the original primary vesicles formed in week 4 and the cranial end of the neural tube now has 3 flexures (bends).


(see also [[BGDA_Practical_7_-_Week_5#Neural_Development|Additional Information]]).


[[File:CNS secondary vesicles.jpg|600px]]


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{|
 
 
 
===Embryo Stages and Events===
 
{| class="prettytable"
| width= "50px" | '''Day'''
| width= "100px" | '''Stage'''
| '''Event'''
 
|-
|-
| <center>29</center>
| {{Neural stage 13 movie}}
|  
| Rapid growth folds the neural tube forming '''3 brain flexures''':
| [http://embryology.med.unsw.edu.au/Notes/endocrine7.htm Pituitary] Week 5  elongation, contacts infundibulum, diverticulum of diencephalon
# [[C#cranial flexure|cranial flexure]] (cephalic)- pushes mesencephalon upwards
# [[P#pontine flexure|pontine flexure]] - generates 4th ventricle
# [[C#cervical flexure|cervical flexure]] - between brain stem and spinal cord


[http://embryology.med.unsw.edu.au/Notes/heart.htm Heart] Week 5 septation starts, atrial and ventricular
|}


[http://embryology.med.unsw.edu.au/Notes/respire.htm Respire] Week 5 left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity)
[[File:Embryo_stage13-_brain_flexures.jpg|600px]]


[http://embryology.med.unsw.edu.au/Notes/respire.htm Respire]  Week 5 to 17 lung histology - pseudoglandular
Neural tube - brain flexures (stage 13)


[http://embryology.med.unsw.edu.au/Notes/Ear.htm Sense - Hearing]  Week 5 cochlear part of otic vesicle elongates (humans 2.5 turns)


|-
{{BGDA Practical 6 - Week 5 Interactive}}
| <center>30</center>
| &nbsp;
| &nbsp;


|-
| <center>31</center>
| &nbsp;
| &nbsp;


|-
| <center>32</center>
| [[Carnegie stage 14|Stage 14]]
| [[File:Stage14_bf1c.jpg|200px|link=Carnegie stage 14]] '''Ectoderm - '''sensory placodes, lens pit, otocyst, nasal placode, primary/secondary vesicles, fourth ventricle of brain


'''Mesoderm - '''continued segmentation of paraxial mesoderm (somite pairs), heart prominence
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'''Head - '''1st, 2nd and 3rd pharyngeal arch, forebrain, site of lens placode, site of otic placode, stomodeum
==Additional Information==
{{Med Prac additional Information}}


'''Body - '''heart, liver, umbilical cord, mesonephric ridge visible externally as bulges.
===Timeline===
{{Week 5 Embryo Stages and Events table}}


'''Limb - '''upper and lower limb buds growing
===Neural Development===


[http://embryology.med.unsw.edu.au/Notes/neuron.htm Neural]  first appearance of the future cerebral hemispheres. Cerebellar plate differentiated to an intermediate layer, and future rhombic lip identifiable [http://www.ncbi.nlm.nih.gov/pubmed/3377191 PMID: 3377191]
{{Carnegie stages CNS images table}}


[http://embryology.med.unsw.edu.au/Notes/git7.htm GIT - Liver]  hepatic gland and its vascular channels enlarge, hematopoietic function appears [http://www.ncbi.nlm.nih.gov/pubmed/9407542 PMID: 9407542]
{{Neural Table}}


|-
====References====
| <center>33</center>
| [[Carnegie stage 15|Stage 15]]
| [[File:Stage15_bf1c.jpg|200px|link=Carnegie stage 15]]


[http://embryology.med.unsw.edu.au/Notes/neuron.htm Neural]  cranial nerves (except olfactory and optic) are identifiable in more advanced embryos [http://www.ncbi.nlm.nih.gov/pubmed/3213956 PMID: 3213956]
<references/>


|-
| <center>34</center>
|
| &nbsp;


|-
| <center>35</center>
| &nbsp;
| [http://embryology.med.unsw.edu.au/Notes/Eye.htm Sense - Eye] 35 to 37 days retinal pigment present


|}


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[[Category:Week 5]]
[[Category:Week 5]]

Latest revision as of 20:51, 12 May 2019

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 fifth week (week 5) following fertilization or clinical GA week 7.

By this week there are many different organs and tissues differentiating throughout the embryo, only a few select systems will be discussed.

Later week 5 development (Stage 15) showing a sagittal section upper half of human embryo.
Stage 15 - Ventral View

Stage15 bf2.jpg

 ‎‎Mobile | Desktop | Original

Stage 15 | Embryo Slides

Cardiovascular

See also Heart Development Timeline - Basic Cardiac Embryology

Respiratory

  • left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity)

Neural

  • Central nervous system - secondary brain vesicles
  • Sensory - Hearing cochlear part of otic vesicle elongates (humans 2.5 turns)
  • Stage 14

    Stage 14

  • Stage 15

    Stage 15

Cardiovascular

Basic Heart Development Timeline.jpg

Heart Development Timeline (see Basic Cardiac Embryology)

Stage13-CVS-icon.jpg
 ‎‎Cardiovascular
Page | Play
Week3 folding icon.jpg
 ‎‎Week 3
Page | Play
Heart1 looping icon.jpg
 ‎‎Heart Looping
Page | Play
Heart1 realign icon.jpg
 ‎‎Heart Realign
Page | Play
Heart1 atrium icon.jpg
 ‎‎Atrial Septation
Page | Play
Heart1 ventricle icon.jpg
 ‎‎Outflow Septation
Page | Play

Atrial Septation

Stage 13 image 067.jpg Stage 13 image 068.jpg

Respiratory

Stage13-GIT-icon.jpg
 ‎‎GIT Stage 13
Page | Play
Week 4 - laryngotracheal groove forms on floor foregut.

Week 5 - left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity)

Week 6 - descent of heart and lungs into thorax. Pleuroperitoneal foramen closes.

Week 7 - enlargement of liver stops descent of heart and lungs.

Month 3-6 - lungs appear glandular, end month 6 alveolar cells type 2 appear and begin to secrete surfactant.

Month 7 - respiratory bronchioles proliferate and end in alveolar ducts and alveolar sacs.

The trachea can be see making its initial branching into the lung bud mesenchyme.

Stage 13 image 070.jpg Gray0961.jpg
Bifurcation of the trachea into the main or primary bronchi, the left and right bronchus. Adult bronchial tree.

Neural

During week 5 the five secondary brain vesicles form from the original primary vesicles formed in week 4 and the cranial end of the neural tube now has 3 flexures (bends).

(see also Additional Information).

CNS secondary vesicles.jpg

Stage13-CNS-icon.jpg
 ‎‎Stage 13 Neural
Page | Play
Rapid growth folds the neural tube forming 3 brain flexures:
  1. cranial flexure (cephalic)- pushes mesencephalon upwards
  2. pontine flexure - generates 4th ventricle
  3. cervical flexure - between brain stem and spinal cord

Embryo stage13- brain flexures.jpg

Neural tube - brain flexures (stage 13)


Week 5 Interactive Component

Attempt the Quiz - Week 5  
BGDsmall.jpg

Here are a few simple Quiz questions that relate to Week 5 (GA week 7) from the lecture and practical.

See your Quiz Result - Answer all the questions, then click "submit" to complete. The page will reload and you can then reopen this table to see your result and feedback.

  

1 The important human cardiogenic event commencing during week 5 is

  heart tube fusion
  heart looping
  heart septation
  heart valve development

2 The 5 secondary brain vesicles listed in rostrocaudal order are:

  myelencephalon - metencephalon - mesencephalon - diencephalon - telencephalon
  telencephalon - diencephalon - mesencephalon - metencephalon - myelencephalon
  prosencephalon - diencephalon - mesencephalon - metencephalon - rhombencephalon
  telencephalon - diencephalon - mesencephalon - myelencephalon - metencephalon
  None of the above.


BGDsmall.jpg
Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8



BGDsmall.jpg
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 5 - Human Embryo Stages and Events (GA week 7) 
Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9
Day
Stage
 Event
29
 pituitary - Week 5 elongation, contacts infundibulum, diverticulum of diencephalon

heart - Week 5 septation starts, atrial and ventricular

respiratory - Week 5 left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity)

respiratory - Week 5 to 17 lung histology - pseudoglandular

hearing - Week 5 cochlear part of otic vesicle elongates (humans 2.5 turns)

30
    
31
    
32
 Stage 14
Stage14 bf1c.jpg
ectoderm - sensory placodes, lens pit, otocyst, nasal placode, primary/secondary vesicles, fourth ventricle of brain

mesoderm - continued segmentation of paraxial mesoderm (somite pairs), heart prominence

Head - 1st, 2nd and 3rd pharyngeal arch, forebrain, site of lens placode, site of otic placode, stomodeum

Body - heart, liver, umbilical cord, mesonephric ridge visible externally as bulges.

Limb - upper and lower limb buds growing

neural - first appearance of the future cerebral hemispheres. Cerebellar plate differentiated to an intermediate layer, and future rhombic lip identifiable[1]

liver hepatic gland and its vascular channels enlarge, hematopoietic function appears[2]

33
 Stage 15
Stage15 bf1.jpg

neural - cranial nerves (except olfactory and optic) are identifiable in more advanced embryos[3]

34
  
35
   vision - 35 to 37 days retinal pigment present
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. ↑ Müller F & O'Rahilly R. (1988). The first appearance of the future cerebral hemispheres in the human embryo at stage 14. Anat. Embryol. , 177, 495-511. PMID: 3377191
  2. ↑ 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.
  3. ↑ Müller F & O'Rahilly R. (1988). The development of the human brain, including the longitudinal zoning in the diencephalon at stage 15. Anat. Embryol. , 179, 55-71. PMID: 3213956

Neural Development

Embryonic Central Nervous System
Stage 13 Stage 14 Stage 16 Stage 21
Human Stage13 sagittal upper half01.jpg

scale bar = 1 mm

Human Stage14 neural01.jpg Human Stage16 neural03.jpg Human Stage21 neural01.jpg
Week 4 Week 5 Week 6 Week 8


Neural Tube Development
Neural Tube Primary Vesicles Secondary Vesicles Adult Structures
week 3 week 4 week 5 adult
neural plate
neural groove
neural tube

Brain
 prosencephalon (forebrain) telencephalon Rhinencephalon, Amygdala, hippocampus, cerebrum (cortex), hypothalamus‎, pituitary | Basal Ganglia, lateral ventricles
diencephalon epithalamus, thalamus, Subthalamus, pineal, posterior commissure, pretectum, third ventricle
mesencephalon (midbrain) mesencephalon tectum, Cerebral peduncle, cerebral aqueduct, pons
rhombencephalon (hindbrain) metencephalon cerebellum
myelencephalon medulla oblongata, isthmus
spinal cord, pyramidal decussation, central canal

References



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


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