UNSW Embryology

Human Embryo Low Power

© Dr Mark Hill (2011)

Acknowledgements

Introduction

These are sections from the Carnegie stage stage 22 Human Embryo is 27mm in size and approximately equal to day 54 - 56 of development. Levels indicated on images are only approximate. The table below takes you to each image with features labelled. From there you can sequentially step through the images or go to the unlabelled or tutorial figures. There is also a high power set of selected images showing details of specific structures.

New 2010 Sections

New Serial Sections Carnegie stage 13 | Carnegie stage 22 | Carnegie stage 22 selected Embryonic Development 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23

Stage 22 Embryo

A1	A2	A3	A4	A5	A6	A7
B1	B2	B3	B4	B5	B6	B7
C1	C2	C3	C4	C5	C6	C7
D1	D2	D3	D4	D5	D6	D7
E1	E2	E3	E4	E5	E6	E7
F1	F2	F3	F4	F5	F6	F7
G1	G2	G3	G4	G5	G6	G7

Stage 22 Embryo (Human) Systems

Coelomic Cavity and Derivatives

Endocrine

Gastrointestinal Tract Development

Head and Neck (pharyngeal arches)

Heart Development

Musculoskeletal Systems

Nervous System

Neural Crest

Organs of Senses

Respiratory System

Skin, Hair and Nails

Urogenital

Placenta and Fetal Membranes

Stage 22 Embryo (Human) Systems

A1 t/s head forebrain	A2 Developing Cortex	A3 t/s head at eye level	A4 Optic Nerve	A5 Optic Retina	A6 Optic Lens
A7 t/s head above mouth	B1 Trigeminal Ganglion	B2 Developing Pituitary	B3 t/s head at ear level	B4 Choroid Plexus	B5 Cochlear & Utricle	B6 Cochlear
B7 t/s upper neck	C1 Larynx	C2 t/s lower neck	C3 Thyroid	C4 Trachea & Oesophagus
C5 t/s upper chest	C6 Thymus	C7 t/s chest	D1 Lung	D2	D3 Foot
D4 t/s chest	D5 Heart valves	D6 Spinal Cord	D7 t/s heart	E1 Heart	E2 Heart Valves
E3 t/s abdomen	E4 Liver	E5 Liver	E6 t/s abdomen	E7 pyloroduodenal junction
F1 t/s peritoneum	F2 Pancreas	F3 Adrenal Gland	F4 t/s peritoneum	F5 Kidney	F6 Renal Corpuscle
F7 t/s peritoneum	G1 Mesonephros	G2 Aorta	G3 Testis	G4 Testis (hp)
G5 t/s pelvis	G6 Bladder, Ureters, Para & Mesonephric Ducts			G7 Bladder, Ureters, Para & Mesonephric Ducts (hp)

About Sections

• The serial sections are showing only 2 specific stages of development, early (Carnegie stage 13/14) and late (Carnegie stage 22).
  • The 6mm Pig embryo is approximately day 42 Human and Carnegie stage 13/14.
  • The 27mm Human embryo is approximately day 56 and Carnegie stage 22.
• Levels indicated on images are only approximate.
• There are also grouped sections for Pig and Human to show how individual slices relate to adjacent levels above and below the selected level.
• The sagittal sections are from a late stage Human embryo.
• The original image sets from microfiche used in both the Medicine and Science Embryology Courses in the School of Anatomy, University of New South Wales.

Serial Images History

The original principle of using serial sections on microfiche cards was developed by Dr M. Smith, Prof. C. Watson and the late Prof. I. Tork in the early 1980's. The original 27mm Human embryo microfiche images were developed by Dr M. Smith and the 6mm Pig Embryo microfiche images by Dr M. Smith and Prof. I. Tork.

Glossary of Terms

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 |

UNSW Embryology ISBN: 978 0 7334 2609 4

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