2- Body Folding & Cavities Flashcards
Human development is divided into three sequential phases, which are…
Growth
Morphogenesis
Differentiation
This phase of human development involves cell division and elaboration of cell products.
Growth
This phase of human development is the development of shape, size, and other features of a particular organ or part of the whole body.
Morphogenesis
Morphogenesis is controlled by the _______ expression and regulation in an orderly sequence.
Gene
Changes in cell fate, cell shape, and cell movement in _________ allow the cells to interact with each other during the formation of tissues and organs.
Morphogenesis
This phase of human development is when cells are organized in a precise pattern of tissues and organs that are capable of performing specialized functions.
Differentiation
The primordium of the _________ _________ appears, which are isolated coelomic spaces in the lateral plate and cardiogenic mesoderm. This is a horse-shoe shaped cavity.
Intraembryonic Coelom
The Intraembryonic Coelom divides the lateral plate mesoderm into what layers?
Somatic (Parietal) Layer of Lateral Plate Mesoderm
Splanchnic (Visceral) Layer of Lateral Plate Mesoderm
This layer of Lateral Plate Mesoderm is continuous with extraembryonic mesoderm covering the amnion.
Somatic (Parietal) Layer
This layer of Lateral Plate Mesoderm is continuous with extraembryonic mesoderm covering the umbilical vesicle.
Splanchnic (Visceral) Layer
This is the term for the Somatic Mesoderm and overlying embryonic Ectoderm that come together to form the body wall.
Somatopleure
This is the term for the Splanchnic Mesoderm and underlying embryonic Endoderm that come together to form the embryonic gut.
Splanchnopleure
Where does folding occur in the embryonic planes, all simultaneously?
Cranial
Caudal
Lateral
What gives constriction for the folding of the embryonic planes?
The junction of the embryo and umbilical vesicle
The embryo goes from a flat, trilaminar embryonic disc to a _________ embryo.
Cylindrical
________ is significant for creating the correct body form. The embryo increases in length, but the lateral edges cannot keep pace.
Folding
Put the following steps in order of embryonic head folding:
A. Overgrowth moves Septum Transversum, Primordial heart, Pericardial Coelom, and Oropharyngeal Membrane to ventral surface.
B. Embryo elongates cranially and caudally (4th week/day 22).
C. Part of the endoderm of the umbilical vesicle is incorporated as the foregut (primordium of pharynx, esophagus, and lower respiratory system).
D. Neural folds project dorsally and overgrow oropharyngeal membrane.
1) B.
2) D.
3) A.
4) C.
Before head folding, the ________ consists of a flattened, horse shoe-shaped cavity
Coelom
What are the 3 components of the horse shoe-shaped coelom?
Pericardial Cavity
Pericardioperitoneal Canal
Intraembryonic Coelom
After head folding occurs, the Pericardial Cavity is ________ and the Pericardioperitoneal Canals run ________ on each side of the foregut.
Ventral
Dorsal
Folding of the caudal end of the embryo is due to the growth of the distal _______ _______.
Neural Tube (Spinal Cord Primordium)
In embryonic tail folding, the ______ ______ or tail region projects over the ______ ______ (future anus).
Caudal Eminence
Cloacal Membrane
In embryonic tail folding, part of the _________ will form the hindgut (descending colon/rectum). The terminal hindgut dilates to form the ________ (rudiment of urinary bladder/rectum).
Endoderm
Cloaca
Before folding the _______ _______ lies cranial to the cloacal membrane, but after folding it lies caudal.
Primitive Streak
T/F. The rapid growth of the SC and Somites produces the right and left lateral folds, which extends ventrally toward the midline and creates a cylindrical embryo.
True
In lateral folding, the abdominal walls form and incorporates endoderm to form the midgut, which is the _______ _______ primordium.
Small Intestine
In lateral folding, the connection between the umbilical vesicle and the midgut is reduced, forming the _________ ________.
Omphaloenteric Duct
As the umbilical cord forms, the communication between what cavities narrows?
Intraembryonic and Extraembryonic Coelomic Cavities
During lateral folding, the amniotic cavity expands and obliterates most of the Extraembryonic Coelom. Amnion forms the epithelial covering of the…
Umbilical Cord
This occurs in approximately 1 in 3000 live births and is protrusion of the viscera. This abdominal defect is to the right of the umbilical cord rather than the midline.
Gastroschisis
How does Gastroschisis differ from and Umbilical Hernia?
In Gastroschisis, bowel is uncovered and floating in the amniotic fluid.
This is a midline bulge of the abdominal wall, located between the Xiphoid Process and Umbilicus. Bowel is not exposed to the amniotic fluid because it remains covered by skin and subcutaneous tissues.
Congenital Epigastric Hernia
The Intraembryonic Coelom will be divided into what cavities?
Pericardial Cavity
Pleural Cavities
Peritoneal Cavity
All the cavities are lined with __________.
Mesothelium
***This is simple squamous
The Parietal wall is derived from _________ mesoderm. This is the future Parietal layer of the Peritoneum.
Somatic
The Visceral wall is derived from _________ mesoderm. This is the future Visceral layer of the Peritoneum.
Splanchnic
Head fold movements reshape the Intraembryonic Coelom, which causes the Pericardial Cavity to relocate ventrally and anterior to the _________.
Foregut
The Pericardial Cavity opens into two __________ _________ that are located dorsal to the foregut and the Septum Transversum.
Pericardioperitoneal Canals
The caudal Peritoneal Cavity is positioned where?
Where Intraembyronic and Extraembryonic Coeloms are continuous
After head folding, the Pericardial Cavity is now cranial to the ________ ________. The heart also repositions and bulges into the Pericardial Cavity.
Septum Transversum
The caudal foregut, midgut, and hindgut are suspended in the Peritoneal Cavity by…
Dorsal Mesentery
The Pericardioperitoneal Canals are lateral to the foregut but dorsal to the _________ _________, which is the primordium of the central tendon of the diaphragm. Partitions form in each Pericardioperitoneal Canal due to growth of the primordial lungs.
Septum Transversum
To divide the body cavity, there is a cranial __________ fold and a caudal ________ fold. The cranial fold is located superior to the lungs and separates Pleural Cavities from the Pericardial Cavity. The caudal fold is located inferior to the lungs and separates Pleural Cavities from the Peritoneal Cavity.
Pleuropericardial
Pleuroperitoneal
_________ folds are located superior to the developing lungs. They enlarge and form __________ membrane that project into the Pericardioperitoneal Canals.
Pleuropericardial
Pleuropericardial
The Pleuropericardial Membranes fuse with mesenchyme ventral to the esophagus during the ______ week. Now, the Pericardial Cavity and Pleural Cavities are separated.
7th
________ _______ will grow into the Pericardioperitoneal Canals and will extend ventrally, causing the cavity to expand.
Bronchial Buds
As the Bronchial Buds grow into the cavity, it splits the mesenchyme into what layers?
Outer Layer = Thoracic Wall
Inner Layer = Fibrous Pericardium (Outer layer of the Pericardial Sac)
Pleuroperitoneal folds enlarge and project into the Pericardioperitoneal Canals, which forms the ________ ________. These form as developing lungs and the Pleural Cavities expand/invade the body wall. Attach dorsolaterally to the abdominal wall.
Pleuroperitoneal Membranes
The Pleuroperitoneal Membranes fuse with the dorsal mesentery of the esophagus and Septum Transversum during the ______ week. The Pleural Cavities and Peritoneal Cavity are now separated.
6th
***Remember, the Pleuropericardial Membranes fuse during the 7th week!
_________ migrate into the Pleuroperitoneal Membranes and complete the closure process. The Pleuroperitoneal opening on the ________ closes slightly before the ________.
Myoblasts
Right
Left
This expands and fuses with the Dorsal Mesentery of the Esophagus and Pleuroperitoneal Membranes. It becomes the Central Tendon of the Diaphragm.
Septum Transversum
This fuses with the Dorsal Mesentery of the Esophagus and Septum Transversum. It becomes the primordial Diaphragm.
Pleuroperitoneal Membranes
This becomes the median portion of the Diaphragm.
Dorsal Mesentery
These grow into the Dorsal Mesentery and become the Crura of the Diaphragm.
Myoblasts
The Pleuropericardial Membranes form partitions that separate separate Pericardial and Pleural Cavities. These membranes contain cardinal _______ and _______ migrating through the Diaphragm.
Veins
Myoblasts
Myoblasts pull Ventral Rami _______ with them, then pass through the Pleuropericardial Membranes. The ________ N. subsequently lies on the Fibrous Pericardium.
C3-C5
Phrenic
This is a posterolateral defect in 1 in 2200 live births. It occurs when the viscera bulges into the Pleural Cavity, causing the lung maturation to be delay and polyhydramnios may be present. The left side is typically impacted and can be corrected at birth.
Congenital Diaphragmatic Henria (CDH)
