48 Hour Chick Embryo Development

48-Hour Chick Embryo

• The maxillary pouch is a rounded or flattened mass on either side of Rathke's pouch.
• The 3rd pharyngeal pouches are large outpocketings of the pharynx, giving a laterally oriented oral cavity.
• The 3rd aortic arches are located beneath the 3rd pharyngeal pouches, but posterior to the hyoid arch.
• The 3rd visceral arch lies between the 2nd and 3rd pharyngeal pouches.

Development of the Heart

• The descending aorta is a fused dorsal aorta.
• The dorsal intersegmental arteries are small blood vessels arising at intervals from the dorsal aorta and the somite.
• The conus arteriosus is a chamber of the heart at the right side of the embryo.
• The atrium is a left-side chamber and the forerunner of the future auricles.
• The ventricle is a large loop chamber of the heart.
• The bulbus cordis is the first heart cavity, extending forward as a finger-like diverticulum anterior to the first mouth.

Development of the Respiratory System

• The laryngotracheal groove is a deep V-shaped depression in the floor of the foregut.
• The thyroid rudiment is a depression in the floor of the pharynx.
• The trachea arises as a ventrocaudal diverticulum of the pharynx, with the lung buds as paired bilateral expansions of the laryngotracheal groove.

Development of the Arteries

• The 1st aortic arch lies beneath the 1st pharyngeal arch.
• The carotid loop is an extension of the 1st aortic arch.
• The internal carotid arteries are paired vessels extending from the carotid loops alongside the forebrain and medial to the optic cups.
• The dorsal aorta is a blood vessel on either side of the notochord, lying above the 1st pharyngeal pouch.
• The 2nd aortic arch lies beneath the 2nd pharyngeal pouches, contained within the 2nd visceral arches (hyoid arches).
• The ventral aorta/aortic sac/truncus arteriosus is the caudal part of the slides when the 1st aortic arch approaches one another and becomes continuous.