BGDA Practical 12 - Embryo to Fetus

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Practical 12: Embryo to Fetus | Second Trimester | Third Trimester | Birth | Neonatal | Abnormalities



Introduction

Identify the development and form of the week 8 embryo (Stage 22 and 23). This 3D reconstruction animations showing specific systems and the histological sections from which these were prepared. There are also virtual slides and selected cross-sections showing specific features.

Then look at the week 10 early fetus and observe developmental changes. The selected mid-sagittal section shows the overall fetal anatomy and the gallery of excerpts have further detailed descriptions of these regions.


Week 8 - Stage 22

Stage22 bf1c.jpg
stage 22, Week 8, 54 - 56 days, 23 - 28 mm

Mesoderm: heart prominence, ossification continues

Head: nose, eye, external acoustic meatus

Body:straightening of trunk, heart, liver, umbilicus: placental cord, midgut herniation, allantois, vitelline duct

Limb: upper limbs longer and bent at elbow, foot plate with webbed digits, wrist, hand plate with separated digits

Straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, ear auricle, scalp vascular plexus, separated digits (fingers), thigh, ankle, umbilical cord

Embryo Anatomy

Now examine selected regions of the Stage 22 embryo and their overall development in the 3D animations.


Stage22 ALL3d.jpg
 ‎‎Systems
Page | Play
Stage22-GIT-icon.jpg
 ‎‎GIT Stage 22
Page | Play
Stage22-CVS-icon.jpg
 ‎‎Cardiovascular
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Stage 22 Neural
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Urogenital
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Skeletal
Page | Play

Virtual Slides

Stage 22 - Eye and Nose

Stage 22 image 008.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Eye

Stage 22 image 008-eye.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Oral Cavity and Inner Ear

Stage 22 image 011.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Larynx and Medulla

Stage 22 image 015.jpg

 ‎‎Mobile | Original

Stage 22 | Embryo Slides
Stage 22 - Neck

Stage 22 image 017.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Atria and Lungs

Stage 22 image 025.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Liver and Ductus Venosus

Stage 22 image 034.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Pelvis

Stage 22 image 048.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Spinal Cord

Stage 22 image 033-spinal-cord.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Stage 22 - Spinal Cord (rotated)

Human Stage22 spinal cord03.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides

Week 8 - Stage 23

Stage23 bf1c.jpg
Week 8, 56 - 60 days, 27 - 31 mm

scalp vascular plexus, eylid, eye, nose, auricle of external ear, mouth, sholder, arm, elbow, wrist, toes separated, sole of foot, umbilical cord

Mesoderm: ossification continues

Head: eyelids, external ears, rounded head

Body: straightening of trunk, intestines herniated at umbilicus

Limbs: hands and feet turned inward

Carnegie Stage 23 MRI movies
Stage23 MRI 3D01 icon.jpg
 ‎‎Embryo Surface
Page | Play
Stage23 MRI 3D02 icon.jpg
 ‎‎Embryo CNS
Page | Play
Stage23 MRI S02 icon.jpg
 ‎‎Sagittal Embryo
Page | Play
Stage23 MRI T01 icon.jpg
 ‎‎Trans. Embryo
Page | Play
Stage23 MRI C01 icon.jpg
 ‎‎Coronal Embryo
Page | Play
Stage23 MRI S01 icon.jpg
 ‎‎Sagittal Head
Page | Play
Stage23 MRI S04 icon.jpg
 ‎‎Sagittal GIT
Page | Play

Stage 23 MRI Movies: Surface | Central Nervous System | CNS (labeled) | Sagittal | Sagittal (labeled) | Transverse | Transverse (labeled) | Coronal | Sagittal Head (labeled) | Sagittal GIT (labeled) | Carnegie stage 23


Week: 1 2 3 4 5 6 7 8
Carnegie stage: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23


Stage 23 Links: Week 8 | System Development | Lecture - Limb | Lecture - Head Development | Lecture - Sensory | Science Practical - Head | Science Practical - Sensory | Science Practical - Urogenital | Historic - Skull Development | Carnegie Embryos | Madrid Embryos | Category:Carnegie Stage 23 | Next Fetal Development
  Historic Papers: 1954 Stage 19-23



Oral Cavity


Week 10 - Fetus (40mm)

Human week 10 fetus 01.jpg

Size comparison embryo-fetus actual.jpg This is an image of the actual size comparison shown in the introduction of the Embryonic stage 13, 23 and Fetal stage 10 week 40mm. This stage of development is after the embryonic period (up to week 8), but only 2 weeks into early fetal development.
Size comparison embryo-fetus.jpg The fetal period is a time of extensive growth in size and mass as well as differentiation of organ systems established in the embryonic period. In particular, the brain continues to grow and develop, the respiratory system differentiates, the urogenital system further differentiates between male/female, endocrine and gastrointestinal tract begins to function.

Compare this 10 week fetus with the earlier Carnegie stage embryos: size, head/body proportions, brain, head, skeletal development.

Note that in the early fetus the midgut remains herniated and will only be taken into the peritoneal cavity on further body wall growth.

There are 4 sections taken in the sagittal plane (moving from the right at Plane A towards the midline at Plane D). Click on the small images (or the text below) to open the linked large image pages.


Related Images

Human- fetal week 10 planes icon.jpg

Fetus (week 10) Planes A (most lateral), B (lateral), C (medial) and D (midline) from lateral towards the midline.

Image Source: UNSW Embryology, no reproduction without permission.







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Practical 12: Embryo to Fetus | Second Trimester | Third Trimester | Birth | Neonatal | Abnormalities



Additional Information

Links: Fetal Development - 10 Weeks | Stage 22 embryo slices


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BGDA: Lecture 1 | Lecture 2 | Practical 3 | Practical 6 | Practical 12 | Lecture Neural | Practical 14 | Histology Support - Female | Male | Tutorial

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2024, March 29) Embryology BGDA Practical 12 - Embryo to Fetus. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/BGDA_Practical_12_-_Embryo_to_Fetus

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G