[ SYSTEMIC EMBRYOLOGY: DEVELOPMENT OF DIGESTIVE SYSTEM AND UROGENITAL SYSTEM ]
Formation of Primitive Gut
- Gastrulation (3-4 weeks) → formation of three germ layers: ectoderm, endoderm, and mesoderm.
- Ectoderm, endoderm, and mesoderm layers fuse to form primitive gut.
- Primitive gut → divided into foregut, midgut, and hindgut.
Development of Digestive System
- Foregut (5-6 weeks) → develops into pharynx, esophagus, stomach, liver, and pancreas.
- Midgut (5-6 weeks) → develops into duodenum, jejunum, ileum, caecum, and appendix.
- Hindgut (5-6 weeks) → develops into large intestine.
Liver and Pancreas
- Liver (5-6 weeks) → develops from endoderm of foregut.
- Liver → divided into two lobes: left and right lobe.
- Pancreas (5-6 weeks) → develops from endoderm of foregut.
- Pancreas → divided into two parts: head, neck, body, and tail.
Development of Kidney, Urinary Bladder, and Ureter
- Intermediate mesoderm (4-5 weeks) → develops into pronephros, mesonephros, and metanephros.
- Metanephros (6-7 weeks) → develops into kidney.
- Kidney (6-7 weeks) → develops into renal cortex and medulla.
- Ureter (6-7 weeks) → develops from metanephric duct.
- Urinary bladder (6-7 weeks) → develops from urogenital sinus.
Development of Male and Female Gonads and Reproductive Organs
- Intermediate mesoderm (4-5 weeks) → develops into urogenital ridges.
- Urogenital ridges (5-6 weeks) → develops into testes (male) and ovaries (female).
- Testes (6-7 weeks) → develops from mesodermal cells.
- Ovaries (6-7 weeks) → develops from mesodermal cells.
- Testes → produce spermatogonia, Sertoli cells, and Leydig cells.
- Ovaries → produce oogonia, follicular cells, and theca cells.
- Male reproductive organs (8-9 weeks) → develops from urogenital folds.
- Female reproductive organs (8-9 weeks) → develops from urogenital folds.
Male Reproductive Organs Diagram
- Testis → produces spermatogonia
- Sertoli cells → nourish spermatogonia
- Leydig cells → produce testosterone
- Epididymis → stores sperm
- Vas deferens → transports sperm
- Prostate gland → produces seminal fluid
- Urethra → transports semen
Female Reproductive Organs Diagram
- Ovary → produces oogonia
- Follicular cells → nourish oogonia
- Theca cells → produce estrogen
- Oviduct → transports egg
- Uterus → supports implantation
- Vagina → transports semen
Flowchart of Development of Gonads and Reproductive Organs
- Intermediate mesoderm → urogenital ridges
- Urogenital ridges → testes (male) and ovaries (female)
- Testes → spermatogonia, Sertoli cells, and Leydig cells
- Ovaries → oogonia, follicular cells, and theca cells
- Male reproductive organs → develops from urogenital folds
- Female reproductive organs → develops from urogenital folds