Embryology

Question 1

What is the function of body cavities ?

Answer 1

They house important organs in the body.

Question 2

What does the abdominopelvic cavity house ?

Answer 2

Digestive and reproductive organs

Question 3

What does the thoracic cavity house ?

Answer 3

Pleural
Pericardial

Question 4

Pleural cavity

Answer 4

Lungs

Question 5

Pericaridal cavity

Answer 5

Heart

Question 6

What are these cavities lined with ?

Answer 6

Lined on the visceral (organ) surface and parietal (body) surface with LUBRICATING fluids in between.

• pleural, pericardial and peritoneal fluid.

Question 7

Briefly describe the development of body cavities

Answer 7

Sperm and egg fuse to form a zygote.

This undergoes division, to form a blastocyst which implants itself into the mother uterus.

2 layers of cells form from the inner cell mass (epiblast and hypoblast)

A 3 layer disc forms from the epiblast via GASTRULATION.

These 3 layers are the ectoderm, mesoderm and endoderm, which develop into all tissues of the body.

The mesoderm differentiates into parietal, intermediate and lateral plate mesoderm.

The lateral plate mesoderm has visceral and parietal layers as it splits to encapsulate the intra-embryonic coelom.

The embryonic disc folds in 2 planes - Cranio-caudally and laterally.

This gives us the body cavities which are subsequently partitioned into the abonialpelvic cavity, the pleural and pericardial cavities.

Question 8

How are the visceral and parietal membranes of body cavities formed ?

Answer 8

Around day 19, a space forms in the lateral plate mesoderm called the intra-embryonic coelom, which separates it into visceral and parietal membranes.

Question 9

Ectoderm

Answer 9

Gives rise to the sensory organs such as skin, eyes and the CNS

Question 10

Mesoderm

Answer 10

Forms connective tissues like muscles and bones

Question 11

Endoderm

Answer 11

Forms the lining of the gut tube in the respiratory system.

Question 12

Function of the serous membrane

Answer 12

It prevents the organs from getting injured as they rub up against each other or against the body wall.

Question 13

What is meant by cranio-cauddle folding ?

Answer 13

Cranio-caudally (head to tail)

Question 14

What is meant by lateral folding ?

Answer 14

It goes from a disc (horseshoe shape) to a tube shape

Question 15

Where is the developing heart and septum transverse located ?

Answer 15

The developing heart and septum transversum (diaphragm) are located cranially

Question 16

Septum Transversum

Answer 16

A structure that gives rise to the adult diaphragm