Spleen

Origin: Mesodermal cells in dorsal mesogastrium

• These cells will form stroma and capsule
• Hematopoietic cells infiltrate spleen
• Dorsal mesogastrium forms: gastrosplenic ligament and splenorenal ligament

NB: Hematopoietic function lost with embryo development. Lymphoid precursor cells migrate into developing organ

Congenital anomalies:

1. Accessory spleen
2. Wandering spleen – lacks one ligament or both
3. Polysplenia/ Chaudhrey’s disease – multiple small accessory spleens

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Suprarenal glands

• Cortex – Mesodermal cells of intraembryonic coelomic epithelium
• On either side of mesentery of gut, proliferates to form fetal cortex

• Medulla – Sympatho – chromaffin cells from neural crest cells (ectoderm)
• Migrate to enter medial aspect of fetal cortex

• Second layer of cells develop from coelomic mesothelium and surrounds fetal cortex to form permanent cortex
• Fetal cortex regresses and disappears after 3rd year of birth
• Permanent cortex differentiates into 3 zones: zona glomerulosa, zona fasiculata and zona reticularis. Complete histological differentiation attained at puberty.

Congenital anomalies:

1. Agenesis
2. Ectopic suprarenal gland – below capsule of kidney
3. Accessory cortical tissue – found on posterior abdominal wall and pelvis
4. Adrenogenital syndrome – hypertrophy of suprarenal cortex and over production of androgens. Results of pseudohermaphroditism in females and premature enlargement of external genitalia in males