Development of Teeth of animals Development of Teeth of animals take place by the both ectoderm and mesoderm. A tooth is a highly modified connective tissue papilla that has undergone a peculiar ossification into dentine and caged by hard enamel elaborated from the epidermis. In addition the cement a bony deposit encrusts the base. The […]

Development of Pituitary Gland in animals The hypophysis cerbri or pituitary gland is an ectodermal derivative and an endocrine gland of double orgin. One part glandular in nature is derived from the epithelium of the stomodeum while the other not so plainly secretory is a specialized extension from the brain. A dorsal evagination the Rathke’s pouch from

Development of Periphery Nervous System The neural crest cells form the ganglionic elements and supporting structures of the peripheral nervous system. The neural crest cells migrate from the dorsal midline. Some of the crest cells aggregate dorsolateral to the aorta forming sympathetic trunk ganglia. Other crest cells continue to migrate ventrally to form abdominal sympathetic

Development of Central Nervous System / CNS Development of Nervous system The primordium of the nervous system is one of the first structures to appear in the embryo. A thickening of the dorsal ectoderm called neural plate develops first along the mid dorsal line of the embryo. By unequal growth the neural plate is folded

Development of Face (Mouth, Lips and Gums, Cheeks, Palates) Development of face The stomodeumor the primitive buccal cavity is formed by the formation of the cranial and lateral foldings and subsequent cranial flexures. It is separated from the pharyngeal cavity by the oropharyngeal membrane which breakdown following the fusion of the left and right mandibular processes.

Development of Liver, Heart, flexor and limb buds Liver and Heart The liver and heart are the largest structures in the early embryo and form a distinctive bulge that can be seen externally. Flexures A series of three differential growth centers develop that result in several flexures along the axis of the embryo soon after

Development of Pharyngeal Pouches in animals The forming branchial arches encroach on the wall of the pharynx. Lateral outpouchings of the pharyngeal endoderm are formed between the branchial arches as the foregut in the pharyngeal region is compressed dorsoventrally. These are called pharyngeal pouches. Each pharyngeal pouch has specific derivatives. The lateral walls of the pharynx

Development of Brachial Region in animals Another early feature that is distinct in the head region involves the mesenchymal structure around the cranial most part of the foregut. Around this area of the foregut, the mesenchyme aggregates and proliferates to form five pairs of arch like structures lateral and ventral to the foregut. The part

Development of Trunk and Body wall in Animals The lateral folding and ventral fusion described in the formation of the sides of the head continues caudally. As the lateral folding behind the head form the cylindrical shaped embryo, it partitions a part of the coelom and part of the yolksac. These are incorporated into the

Development of Head Region in animals Neural Plate and neural groove The first indication of the formation of the head is a thickening of the ectoderm over the cranial end of the notochord. The thickening is the precursor of the brain which is referred as neural plate. The folds develop from neural plate fuse with one