Table Of ContentEmbryology
at a Glance
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Embryology
at a Glance
Second Edition
Samuel Webster
Senior Lecturer in Anatomy & Embryology
Medical School
Swansea University
Swansea, UK
Rhiannon de Wreede
Honorary Lecturer
College of Medicine
Swansea University
Swansea, UK
This edition first published 2016 © 2016 by John Wiley & Sons, Ltd
Previous edition © 2012 John Wiley & Sons, Ltd
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Cover image: ©Steve Atherton
Set in 9.5/11.5pt Minion by SPi Global, Pondicherry, India
1 2016
v
Contents
Preface vii
Acknowledgements viii
List of abbreviations ix
Timeline x
About the companion website xi
Part 1
Early development 1
1
Embryology in medicine 2
2
Language of embryology 4
3
Introduction to development 6
4
Cell signalling genes 8
5
Embryonic and foetal periods 10
6
Mitosis 12
7
Meiosis 14
8
Spermatogenesis 16
9
Oogenesis 18
10
Fertilisation 20
11
From zygote to blastocyst 22
12
Implantation 24
13
Placenta 26
14
Gastrulation 28
15
Germ layers 30
16
Stem cells 32
17
Neurulation 34
18
Neural crest cells 36
19
Body cavities (embryonic) 38
20
Folding of the embryo 40
21
Segmentation 42
22
Somites 44
Part 2
Systems development 47
23
Skeletal system (ossification) 48
24
Skeletal system 50
25
Muscular system 52
26
Musculoskeletal system: limbs 54
27
Circulatory system: heart tube 56
28
Circulatory system: heart chambers 58
29
Circulatory system: blood vessels 60
30
Circulatory system: embryonic veins 62
31
Circulation system: changes at birth 64
32
Respiratory system 66
33
Digestive system: gastrointestinal tract 68
34
Digestive system: associated organs 70
35
Digestive system: congenital anomalies 72
36
Urinary system 74
vi
37
Reproductive system: ducts and genitalia 76
38
Reproductive system: gonads 78
39
Endocrine system 80
40
Head and neck: arch I 82
41
Head and neck: arch II 84
42
Head and neck: arch III 86
43
Head and neck: arches IV–VI 88
44
Central nervous system 90
45
Peripheral nervous system 92
46
The ear 94
47
The eye 96
48
Antenatal screening 98
Self-assessment MCQs 100
Self-assessment MCQ answers 104
Self-assessment EMQs 105
Self-assessment EMQ answers 107
Glossary 108
Index 112
vii
Preface
W
e wrote this book for our students; those studying medicine
with us, those listening to the podcasts wherever they may
be, and those studying the other forms that biology takes
on their paths to whatever goals they may have in life. We have
introduced many students to the fascinating and often surprising
processes of embryological development, and we hope to do the
same in this book. It is written for anyone wondering, “where did I
come from?”
The content of this book extends beyond the curricula of most
medicine, health and bioscience teaching programmes in terms of
breadth, but we have limited its depth. Many embryology textbooks
cover development in detail, but students struggle to get started,
and to get to grips with early concepts. Hopefully we have addressed
these difficulties with this book.
We hope that you will use this book to begin your studies of
embryology and development, but also that you will return to it
when preparing for assessments or checking your understanding.
You will find example assessment questions at the end of the book
as well as a Glossary.
Let this be the start of your integration of embryonic development
with anatomy, to the ends of improved understanding and better
patient care or scientific insight.
Samuel Webster
Rhiannon de Wreede
viii
Acknowledgements
T
hank you to Kim and Robin for being so encouraging and
putting up with the time demands of completing this book.
We would also like to thank the editors at Wiley‐Blackwell
for leading us through this process and for their support and
encouragement, and Jane Fallows for all her work with the
illustrations.
ix
List of abbreviations
AER
Apical ectodermal ridge
CAM
Cell adhesion molecule
CN
Cranial nerve
CSF
Cerebrospinal fluid
ECMO
Extracorporeal membrane oxygenation
FGF
Fibroblast growth factor
FSH
Follicle stimulating hormone
GnRH
Gonadotrophin releasing hormone
HbF
Foetal haemoglobin
hCG
Human chorionic gonadotrophin
hCS
Human chorionic somatomammotrophin
IUD
Intrauterine device – contraceptive device
IUGR
Intrauterine growth restriction
IVC
Inferior vena cava
IVD
Intervertebral disc
IVF
In vitro fertilisation
LH
Luteinising hormone
LMP
Last menstrual period
PDA
Patent ductus arteriosus
PFO
Patent foramen ovale
PTH
Parathyroid hormone
PZ
Proliferating zone
Rh
Rhesus
SVC
Superior vena cava
TGF
Transforming growth factor
ZPA
Zone of polarising activity
x
Timeline
Language of embryology (Chapter 2)
Introduction to development (Chapter 3)
Embryonic and foetal periods (Chapter 4)
Spermatogenesis (Chapter 7)
Oogenesis (Chapter 8)
Fertilisation (Chapter 9)
From zygote to blastocyst (Chapter 10)
Implantation (Chapter 11)
Placenta (Chapter 12)
Gastrulation (Chapter 13)
Formation of germ layers (Chapter 14)
Formation of the heart tube (Chapter 25)
Folding of the embryo (Chapter 18)
Neurulation (Chapter 15)
Segmentation (Chapter 19)
Formation of blood vessels (Chapter 27)
Somite development (Chapter 20)
Development of digestive system (Chapter 31)
Development of body cavities (Chapter 17)
Development of urinary system (Chapter 34)
Development of head and neck structures (Chapter 38–41)
Development of the eye (Chapter 45)
Migration of neural crest cells (Chapter 16)
Development of muscular system (Chapter 23)
Development of the ear (Chapter 44)
Development of central nervous system (Chapter 42)
Cranial neuropore closes (Chapter 15)
Development of endocrine system (Chapter 36)
Caudal neuropore closes (Chapter 15)
Heart tube divides into four chambers (Chapter 26)
Development of skeletal system (Chapter 22)
Development of peripheral nervous system (Chapter 43)
Development of musculoskeletal system (Chapter 24)
Development of respiratory system (Chapter 30)
Formation of the atrial septa (Chapter 26)
Ossification of skeletal system (Chapter 21)
Development of reproductive system (Chapter 35)
Foetus can hear external sounds (Chapter 44)
0
10
20
30
Days
Weeks
40
50
60
10
20
30
40
Death
Menopause
Days
Weeks
Adult
Puberty
Adult
0
10
20
30
40
50
60
10
20
30
40
Death
Puberty
Menopause
xi
About the
companion website
Don’t forget to visit the companion website for this book:
www.ataglanceseries.com/embryology
There you will find valuable material designed to enhance your
learning, including:
• Podcasts and animations hosted on Dr Webster’s website
• An additional instructor resource comprising an image bank
of all the figures from the book.
Scan this QR code to visit the companion website
1
Early development
Chapters
1
Embryology in medicine 2
2
Language of embryology 4
3
Introduction to development 6
4
Cell signalling genes 8
5
Embryonic and foetal periods 10
6
Mitosis 12
7
Meiosis 14
8
Spermatogenesis 16
9
Oogenesis 18
10
Fertilisation 20
11
From zygote to blastocyst 22
12
Implantation 24
13
Placenta 26
14
Gastrulation 28
15
Germ layers 30
16
Stem cells 32
17
Neurulation 34
18
Neural crest cells 36
19
Body cavities (embryonic) 38
20
Folding of the embryo 40
21
Segmentation 42
22
Somites 44
Part 1
