Embryology | Master Of Medicine

Category Archives: Embryology

Development of genital structures in males and females

Genital structures in males

  1. Genital tubercle -Glans penis
  2. Urogenital sinusĀ  -Corpus spongiosum,Bulbourethral glands(Cowpers),Prostrate
  3. Urogenital folds -Ventral shaft of penis
  4. Labioscrotal swelling -Scrotum
  5. Gubernaculum -Gubernaculum testis
  6. Mesonephric/Wolffian duct -Epididymis,Ejaculatory duct,Ductus deferens
  7. Paramesonephric/Mullerian duct -Appendix of testis,prostatic utricle

Genital structures in females

  1. Genital tubercle – Glans clitoris
  2. Urogenital sinus -Greater vestibular glands of bartholin,Urethral and paraurethral glands of skene
  3. Urogenital folds -Labia minora
  4. Labioscrotal swelling -Labia majora
  5. Gubernaculum – Ovarian ligament and round ligament
  6. Wolffian duct – Duct of epoophoron
  7. Mullerian duct -Uterus,Fallopian tube,upper part of vagina


Derivatives of dorsal and ventral mesogastrium

The derivatives of dorsal and ventral mesogastrium are

Dorsal mesogastrium

  1. Greater omentum
  2. Gastrosplenic ligament
  3. Gastrophrenic ligament
  4. Lienorenal ligament

Ventral mesogastrium

  1. Lesser omentum
  2. Falciform ligament
  3. Coronary ligament
  4. Right and left triangular ligament

Diaphragm development

Septum transversum

Image via Wikipedia

Diaphragm develops from the following components:

  1. Septum transversum
  2. Pleuroperitoneal membranes
  3. Ventral and dorsal mesenteries of esophagus
  4. Mesoderm of body wall
  5. Cervical myotomes

Septum transversum forms the central tendon of the diaphragm



Anatomical structures and their Origin in general


Structures meeting the external environment are ectodermal in origin:Skin
Mucous covering of parts of external orifices

  1. Oral cavity
  2. Anal canal
  3. Vagina
  4. Urethra


  1. Serous lining of body cavities and endothelial lining of CVS,lymphatics and lymphnodes
  2. Bone,muscle,cartilage
  3. Connective tissue of skin
  4. Blood vessels


Epithelial lining of structures meeting alimentary canal

  1. GIT
  2. Ducts and acini of salivary glands(except parotid)
  3. Eustachian tube and middle ear
  4. Biliary system
  5. Parenchyma of the liver
  6. Respiratory system
  7. Ducts and acini of pancreas

Genital ridge,wolffian duct,mullerian duct

Development of female genital organs

Genital ridge

  1. Infundibulopelvic ligament
  2. Ovary
  3. Ovarian ligament
  4. Round ligament

Mullerian duct/Paramesonephric duct

  1. Fimbria
  2. Fallopian tube
  3. Uterus
  4. Upper 3/4th of vagina

Wolffian duct/Mesonephric duct

  1. Epoopheron
  2. Paroopheron

Development of male genital organs

Mullerian duct

  1. Appendix of testis
  2. Prostatic utricle

Wolffian duct

  1. Vas deferens
  2. Seminal vesicle
  3. Ejaculatory ducts
  4. Epididymis
  5. Appendix of epididymis
  6. Mesodermal part of prostate

Urinary(from wolffian)

  1. Collecting tubes of kidney
  2. Calyces
  3. pelvis
  4. Ureter
  5. Trigone of bladder
  6. Posterior wall of prostatic urethra cranial to opening of ejaculatory ducts

Development of kidney and reproductive system

Mesonephric duct/Wolffian duct- Males

Paramesonephric duct/Mullerian duct-Females

Genital ridge-Ovary and testis


Metanephros gives rise to secretory/excretory part of kidney.

Pronephros and mesonephros disappear.

If ureteric bud and metanephros doesn’t fuse, agenesis of kidney occurs.


While Ovum is in the Ovary it is in Primary Oocyte stage.

Just before ovulation meiosis takes place and Secondary Oocyte is formed and first Polar body expelled.

The secondary Oocyte Immediately begins second Meiotic division but is arrested in metaphase.
This division is completed only when the sperm penetrates the ovum and the second polar body is expelled

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