fore-gut

Peritrophic membrane: a funnel-like extension of the fore-gut, extending back tube-like, through the chylific ventricle in some insects.

Explanation of Terms Used in Entomology John. B. Smith

—In the lateral walls of the anterior part of the fore-gut five pharyngeal pouches appear (Fig. 42); each of the upper four pouches is prolonged into a dorsal and a ventral diverticulum.

I. Embryology. 12. The Branchial Region 1918

—The primitive digestive tube consists of two parts, viz.: (1) the fore-gut, within the cephalic flexure, and dorsal to the heart; and (2) the hind-gut, within the caudal flexure (Fig. 977).

XI. Splanchnology. 2. The Digestive Apparatus 1918

—The upper part of the fore-gut becomes dilated to form the pharynx (Fig. 977), in relation to which the branchial arches are developed (see page 65); the succeeding part remains tubular, and with the descent of the stomach is elongated to form the esophagus.

XI. Splanchnology. 2. The Digestive Apparatus 1918

Between the fore-gut and the hind-gut there exists for a time a wide opening into the yolk-sac, but the latter is gradually reduced to a small pear-shaped sac (sometimes termed the umbilical vesicle), and the channel of communication is at the same time narrowed and elongated to form a tube called the vitelline duct.

I. Embryology. 9. Separation of the Embryo 1918

The intervening mesoderm is pressed aside and the ectoderm comes for a time into contact with the entodermal lining of the fore-gut, and the two layers unite along the floors of the grooves to form thin closing membranes between the fore-gut and the exterior.

I. Embryology. 12. The Branchial Region 1918

As the liver undergoes enlargement, both it and the ventral mesogastrium of the fore-gut are gradually differentiated from the septum transversum; and from the under surface of the latter the liver projects downward into the abdominal cavity.

XI. Splanchnology. 2i. The Liver 1918

The rudiment of the heart is situated immediately below the fore-gut and consists of a short stem.

V. Angiology. 3. Development of the Vascular System 1918

The lung buds meantime have grown out from the fore-gut, and project laterally into the forepart of the pleuro-peritoneal cavity; the developing stomach and liver are imbedded in the septum transversum; caudal to this the intestines project into the back part of the pleuro-peritoneal cavity (Fig. 55).

I. Embryology. 13. Development of the Body Cavities 1918

By the forward growth and flexure of the head the pericardial area and the anterior portions of the primitive aortæ are folded backward on the ventral aspect of the fore-gut, and the original relation of the somatopleure and splanchnopleure layers of the pericardial area is reversed.

V. Angiology. 3. Development of the Vascular System 1918