Ga2 - Development Of Body Cavities

Front 1

What is found in the following 4 cavities:
1 Pericardial Cavity
2 Thoracic Cavities
1 Peritoneal Cavity

Back 1

1 Pericardial Cavity (Heart)
2 Thoracic Cavities (Lungs)
1 Peritoneal Cavity (GI Tract)

Front 2

These cavities are lined by what and what are it's 2 components

Back 2

Lined by mesothelium - simple squamous

Visceral layer covers organs

Parietal layer coats body wall

There is a space present between these 2 layers

Front 3

Potential Space vs. Real Space. What is a hemothroax and what does it prevent?

Back 3

The peritoneal cavity is often described as a potential space.

-Potential spaces filled with a little fluid and organs

-If a body cavity fills with blood, it becomes a real space.

A hemothorax occurs when the thoracic cavity fills with blood. This prevents re-inspiration of the lung.

Front 4

Four body cavities derived from a single embryonic cavity, called the...

Back 4

-Four body cavities derived from a single embryonic cavity, the Intraembryonic Coelom
-Intraembryonic coelom is partitioned into 4 separate body cavities by 3 partitions.

*All four body cavities were once connected. This is important because there can be a herniation of peritoneal cavity into the throacic cavity. For example, in a diaphragmatic hernia, abdominal viscera herniates into the throacic cavity. In a hiatal hernia, gastrointestinal viscera dissects up into the mediastinal cavity.

Front 5

Communication between Intraembryonic Coelom (IEC) and Extraembryonic Coelom (EEC)

Back 5

-Intraembryonic (IEC) and extraembryonic coeloms (EEC) are initially in communication

-Growth of amnionic folds restricts communication between IEC and EEC

Front 6

The intraembryonic coelum (IEC) is located between what two areas.

Back 6

This lateral plate mesoderm will divide into splancnic mesoderm and somatic mesoderm (i.e. somites). The space between these 2 areas is the intraembryonic coelum (IEC).

Front 7

What connects the pericardial and peritoneal cavity during development?

Back 7

•The pericardioperitoneal canal connects the pericardial and peritoneal cavity. These must be separated.

Front 8

Amnionic Folds Close off IEC and EEC - when is there no longer communication between IEC and EEC?

Back 8

-As amnionic folds grow, communication between IEC and EEC progressively restricted

-Eventually, when ventral body wall is completed, there is no longer communication between IEC and EEC. Formation of the ventral body wall restricts the connection between the gut tube and yolk sac.

(The amniotic folds grow in from the head and tail ends into the umbilicus. The amniotic folds as well as the lateral folds all converge at the umbilicus, which is the last point at which continuity between the IEC and EEC exists.)

Front 9

Separation of Pleural and Pericardial Cavities - Lung buds arise and grow which way and into what? Pleuropericardial membranes arise and grow which way and fuse where?

Back 9

-Lung buds arise medially and grow laterally into pericadioperitoneal canals

-Pleuropericardial membranes arise laterally and grow medially

-Pleuropericardial membranes fuse in midline and with mediastinal CT

Front 10

Separation of Pleural and Peritoneal Cavities - Diaphragm forms from four rudiments. The diaphragm is the barrier between the...

Back 10

(1) Septum transversum

(2) Pleuroperitoneal membrane

(3) Dorsal mesentery of esophagus

(4) Muscular ingrowth from body wall

•The diaphragm is the barrier between the pericardium/pleural cavities and peritoneal cavities.

Front 11

What is the septum transversum and what does it form most of? What will it eventually form?

Back 11

•The septum transversum is a mass of mesenchyme that will form most of the mass of the diaphragm. It starts dorsally and expands ventrally.

-Specficially, septum transversum will form the central tendon of the diaphragm.

Front 12

The pleuroperitoneal membrane grows toward and fuses with what?

Back 12

The pleuroperitoneal membrane starts dorsolaterally and grows towards the septum transversum, where they fuse.

Front 13

The muscular ingrowth from the body wall forms a lot of...

Back 13

The muscular ingrowth from the body wall forms a lot of the skeletal muscle of the diaphragm

Front 14

Congenital Diaphragmatic Hernia (CDH) - What is the patent foramen of Bochdalek and how does it form? What type of defect is it and on what side of the body does it usually occur?

Back 14

-There are a few ways to have a breakdown in the structure of body cavities.

-If the pleuroperitoneal membrane does not fuse completely, there will be a hole or holes in the diaphragm. This is called patent foramen of Bochdalek.

-Posterolateral diaphragmatic defect; 85-90% on left side

-They occur posterolaterally because the pleuroperitoneal membrane fuses with the septum transversum on its posterolateral side.

-It is not clear why most patent foramina of Bochdalek are on the left side.

Front 15

Congenital Diaphragmatic Hernia (CDH) - what can happen to the peritoneal organs in the thoracic cavity? Can it be corrected? What does Pulmonary hypoplasia have to do with CDH?

Back 15

-In this condition, peritoneal organs can herniate into the thorax.

-The condition can be minor or fatal depending on how much of the organ is in the cavity, and how much it effects the heart and lungs.

-The condition can often be corrected surgically.

-CDH involves three major defects.
1)A failure of the diaphragm to completely close during development.
2)Herniation of the abdominal contents into the chest
3)Pulmonary Hypoplasia - underdevelopment of the lungs b/c abdominal contents protrude into the chest

Front 16

In severe cases of CDH, what can herniate through the diaphragm?

Back 16

•In severe cases, large chunks of bowel can herniate through the diaphragm, compress the lung, and move the heart to the right. This level of abnormality would be surgically correctable.

Front 17

Treatment of CDH

Back 17

-Early detection (ultrasound) and intrauterine surgical repair

-If minor, and pulmonary hypoplasia and heart development normal, postnatally reduce loops of bowel into peritoneal cavity and surgically patch foramen of Bochdalek

-If major, with profound pulmonary hypoplasia and heart defects, usually fatal


•Intrauterine surgical repair is only done if the herniation is life threatening to the baby and is found early. Otherwise, corrective surgery can be done after birth.
•The surgion enters the uterus of the mother, into the body cavities of the fetus and moves the loop of bowel back inside.
•In cases where a lot of viscera has herniated, the baby will not survive due to the pulmonary hypoplasia and cardiovascular defects. The baby will be still born.