Endocrine System Embryo & Histology

A Reviewer for MicroAnatomy Practicals

Dorsal Pancreas Anlage: Endoderm Fate: Pancreas (head part) Secretion: (islets of langerhans) A cells - glucagon B cells - insulin D cells - somatostatin G cells - gastrin F cells – pancreatic polypeptide

Rathke’s pouch

Germ Layer: Ectoderm Anlage: Stomodeum Fate: Anterior Pituitary gland (adenohypophysis)

Ultimobrachial body

Germ layer: Endoderm Fate: parafollicular cells Secretion: calcitonin

Thyroid gland

Germ layer: Endoderm Anlage: primordial thyroid gland Fate: Thyroid gland Secretion: Thyroid hormones (T3&T4)

Undifferentiated Gonad

Male: Germ layer: Mesoderm Fate: Testis *leydig cells - testosterone

Female: Germ layer: Mesoderm Fate: Ovaries *theca interna – estrogen *granulosa cells - progesterone

Pancreas: Islets of Langerhans

Organ: Pancreas Secretion: (islets of langerhans) A cells - glucagon B cells - insulin D cells - somatostatin G cells - gastrin F cells – pancreatic polypeptide

Adrenal gland

Layer: Zona fasciculata Secretion: glucocorticoids (corticosterone, cortisone, cortisol)

Layer: Zona glomerulosa Secretion: mineralocorticoid (aldosterone)

Parenchema: Chromaffin cells

Zona reticularis Secretion: Androgen (sex hormones)

Adrenal Cortex

Adrenal medulla

Adrenal Gland

• Parenchema: Chromaffin cells

• Secretion: Norepinephrine & Epinephrine

Adrenal medulla

Medullary veins

Pineal gland

Brain sands or acervulus (concretions of calcium carbonate and calcium phosphate)

Germ layer: Ectoderm Parenchema: pinealocytes Secretion: Melatonin

Anterior pituitary gland (Pars distalis)

Anlage: Stomodeum / Rathke’s pouch Germ layer: ectoderm Secretion: FSH, LH, GH, PRL, ACTH, TSH Parenchema: Chromophils

Anterior Pituitary gland (pars tuberalis)

Anlage: Stomodeum / Rathke’s pouch Germ layer: ectoderm Secretion: none

Ant. Pituitary gland (Pars intermedia)

Anlage: Stomodeum / Rathke’s pouch Germ layer: ectoderm Secretion: POMC

Rathke’s cyct

Pars nervosa

Posterior Pituitary gland (Pars nervosa)

Anlage: Infundibulum Germ layer: ectoderm Secretion: oxytocin and ADH Parenchema: pituicytes

Placenta

Chorionic Villi

Specific structure: Syncitiotrophoblast Secretion: human chorionic gonadotrophin (Hcg)

Ovary

Specific structure: theca interna Secretion: Estrogen

Specific structure: zona granulosa cells Secretion: progesterone

Testis

Germ Layer: Mesoderm Structure: Leydig cells Secretion: testosterone

Specific structure: sertoli cells Secretion: inhibin