Veterinary anatomy all topics, Schemes and Mind Maps of Anatomy

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Development of Endocrine

Glands

By- Dr. Satish Kumar Pathak Assistant Professor, Department of Veterinary Anatomy, FVAS, BHU

Pituitary gland (Hypophysis

cerebri)

⚫ In the Dorsal midline of stomodaeum an evagination is develops and extends towards the ventral aspect of diencephalon. This evagination is called as Rathke’s pouch ⚫ The Rathke’s pouch loses its connection with stomodaeum and develops into adenohyphophysis ⚫ From the ventral midline of diencephalon an evagination is develops as an infundibulum and further develops as neurohyphophysis ⚫ The adenohypophysis and neurohyphophysis fused together and is called as pituitary gland (Hypophysis cerebri) ⚫ Adenohypophysis is oral ectoderm derivative and neurohypophysis is neural ectoderm derivative

Pineal gland (Epiphysis cerebri)

⚫ In the dorsal caudal part of the diencephalon (roof) the neuro epithelium forms an evagination

⚫ These evagination further develops into pineal gland. The neuro epithelial cells differentiates into pinealocytes and glial cells

⚫ The developing pineal gland is covered by pia matter derived connective tissue

Thyroid gland

⚫ It is develops as a ventral midline diverticulum from the floor of the foregut at the level of 1 st^ and 2 nd^ pharyngeal arches ⚫ The caudal end of the diverticulum bulges and extends ventrally towards caudal direction into the underlying mesoderm ⚫ The connection of the diverticulum with the foregut is called as entoglossal duct ⚫ In the further development the end bud bifurcates and extends beyond the developing larynx. The bifurcated end bud develops as thyroid lobes

Thymus

⚫ It is develops from the ventral segments of 3 rd^ pharyngeal pouches ⚫ The ventral pouches extends further backward and meets infront of the developing heart ⚫ The thymic primordial cells proliferates and fills the cavities of the pouches and converts them into solid masses ⚫ The caudal migration of developing heart draws the thymus into the anterior mediastinum and gives the the thymus Y shape ⚫ The neural crest cells surround the thymus and forms connective tissue capsule ⚫ The capsule extends numerous septa into the gland and divides into lobes and lobules

Pancreatic islets

⚫ Within the developing pancreas, clusters of cells bud off the developing exocrine component of the pancreas forming endocrine structures referred to as the pancreatic islets or islets of Langerhans

⚫ Cells within these islets differentiate into particular cell types, each with the capability of producing specific endocrine secretions

⚫ These endocrine cells, which are designated as α‐cells, β‐cells and δ‐cells, produce glucagon, insulin and somatostatin respectively