UNSW Embryology
Embryology Home Page

Coelomic Cavity and its Derivatives - text only page
School of Anatomy

Page 1 | 2 | 3 | 4 | 5 | WWW

Cell Biology Lab

Page Links*Reading *Computer Activities* Objectives*Learning activities *Serial Sections*Self Assessment Questions*Abnormalities*OMIM Database*About Notes*Next Page*Pig Embryo*Human Embryo*Selected Human (high power)

Page 1 | Introduction
Page 2 | Questions | Abnormal | OMIM | Refs
Page 3 | Pig Stage 13/14
Page 4 | Human (Stage22)
Page 5 | Selected Highpower
Text only page | WWW Links

Introduction

The intraembryonic coelom is the primitive cavity that lies within the developing embryo that will form the 3 major body cavities: pericardial, pleural, peritoneal. The coelom forms very early in embryogenesis and is much later paritioned inferiorly by the diaphragm and pleuroperitoneal membrane; and superiorly initially by the pleuropericardial fold between the heart and lungs.

The intraembryonic coelom communicated through coelomic portals (at the level of midgut herniation) with the extraembryonic coelom. All cavities are fluid filled and developing organs push against a wall of the cavity, generating a double coat (serosal/adventital) surrounding an organ (for example the lungs). The serous membrane is the epithelium (squamous) and its associated underlying loose connective tissue.

Reading

  • Human Embryology (2nd ed.) Larson Ch6 p127-146
  • The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Ch9: p174-184
  • Before we Are Born (5th ed.) Moore and Persaud Ch10 p181-195
  • Essentials of Human Embryology Larson Ch6 p81-93
  • Human Embryology Fitzgerald and Fitzgerald Ch5 p29-32, Ch7 p47,48
  • Additional References
  • Search PubMed- Medline

Computer Activities

UNSW Embryology:

Embryo Images Unit:

Unit: Early Cell Populations & Establishment of Body Form, Body Cavities

Objectives

  • Describe the development of the intra- and extra-embryonic coeloms.
  • Describe the processes involved in the development of the three divisions of the intra-embryonic coelom; pericardium, pleural cavities and peritoneum.
  • Describe the fate of the extra embryonic coelom.
  • Describe the development of the diaphragm.

Learning activities

  • Review the development of the 3-layered embryo, with particular reference to the antero-posterior and lateral folding processes.
  • Examine the 6mm pig and 27mm human embryo microfiche cards identifying the main features of the developing coelom.
  • Identify the diaphragm in the 27mm human embryo and relate this to the development of the diaphragm.
  • Discuss the developmental anomalies associated with the formation of the diaphragm.

Development Overview

 

Extraembryonic Coelom

cavity surrounding the developing embryo
coelomic portals
transient communication between extra/intracoelom

Intraembryonic Coelom

horseshoe shaped structure forms 3 main cavities

Neural Tube
percardial cavity
Ventricular space
L/R pleural cavities
Spinal canal
peritoneal cavity
(not part of this section)
(see neural dev notes)

DEVELOPMENTAL ABNORMALITIES

DIAPHRAGMATIC HERNIA (POSTERO-LATERAL)

OMIM Database Online Mendelian Inheritence in Man Database. OMIM

Internet Search OMIM database with the keyword "coelom" "peritoneum" "pleural cavity" or the above abnormality names.

Note: This database is an external link, not accessible from some computers in the School of Anatomy.
A is available for these computers.

PubMed Database

Online Medline Database PubMed- Medline

National Library of Medicine (US) search service to access the 9 million citations in MEDLINE and Pre-MEDLINE (with links to participating on-line journals), and other related databases.

Internet Search this database or use the form below with the keyword or related topics. You can also restrict to reviews or by date published.

  • Note: This database is an external link, not accessible from some computers in the School of Anatomy.
  • A Selected List of References from March 1999 search results for and is available for these computers.

Search Field: Mode:

PubMed

Self Assessment Questions

 

1. What are the four main developmental components of the diaphragm.

2. What is the septum transversum

3. Describe the developmental observations associated with diaphragmatic hernia and its consequences on the individual with the malformation.

4. How does the innervation of the diaphragm develop.

Terms

*Pig Embryo*Human Embryo*Selected Human (high power)

Pig Embryo

G6-G7: The extent of the coelomic cavity is best seen on the sagittal sections of the pig embryo. G7: identify the pericardial cavity and its continuation posteriorly into the still small pleural cavity (pleuroperitoneal canals).The pleuroperitoneal (pericardio-peritoneal) canal.

G6: one of the lung buds is seen embedded in the dense tissue that is surrounded by the coelomic cavity.The abdominal (peritoneal) cavity is clearly continuous with the extra embryonic coelom and parts of the intestinal loop and accompanying mesentery are visible entering the umbilical region.

C5: The most cranial part of the coelom visible in cross sections is the pericardial cavity and from this level caudally it can be seen extending to the level of the liver, but anterior to it (D6). B7-C5: Posteriorly and cranially this cavity communicates with the primitive pleural cavity which are two canals connecting the pericardial and peritoneal cavities (C6-7, D1-6).

C5-7: These two channels are separated from the pericardium by a fold containing the common cardinal veins either side. (Pleuropericardial folds - see development of diaphragm).

D2-6: The peritoneal cavity is extensive; it consists of two, adjoining halves and a small cranial outpocketing next to the stomach, the lesser sac. Further caudally this cavity extends as far as the region of the urorectal septum E7 (tail). Much of the peritoneal cavity is occupied by the two parts of the mesonephros, which reduce most of the cavity to two crescent-shaped clefts.

Human Embryo

In the human embryo, the separation of the three cavities of coelom is complete.

D1-7&E1-4 : The pericardial cavity.

Dl-7, E1-7: The pleural cavity, almost the same frames, indicating the nearby equal extent of the two cavities at this stage, but also that eventually the pleural cavities will become much larger. E3-7: The diaphragm can be seen as a thin, distinct membrane around the liver. Two derivatives of the coelomic epithelium are to be observed here.

E6-7, F1-3: The adrenal glands. Notice the large fetal cortex, (most of the gland) and the narrow (more compact and darker staining) early permanent cortex encapsulating it.

F1-3: The spleen develops in the dorsal mesogastrium and appears as a dense body on it lateral to the left adrenal gland and kidney. Review in Endocrine Development.

F3-7, G1: The gonads are also in part derivatives of the coelomic epithelium but they will be discussed with the rest of the genital system.

G4-5: The caudal extent of the peritoneal cavity; this appears as the rectovesical pouch in the male or as the rectouterine pouch in the female.

Human Embryo- high power

 

E6: The histological appearance of the fetal adrenal cortex is seen.

F3: Fetal and permanent adrenal cortex. The medulla of the adrenal gland is of neural crest origin and it is not yet encapsulated by the cortex.

About Notes

  • Notes from the Embryology Program compiled and written by Dr Mark Hill. Some notes derived from historic class notes.
  • Note Links to OMIM Entries are copies of originals for computers without internet access. Computers with internet access can directly access the database.

Links
Serial Sections Homepage
Human Homepage
Pig Homepage

m.hill@unsw.edu.au
Date Last Modified: 11/3/99
This site maintained by Dr M. Hill