00:00 / 00:00
Organ system development
Development of the cardiovascular system
Development of the ear
Development of the eye
Development of the face and palate
Pharyngeal arches, pouches, and clefts
Development of the digestive system and body cavities
Development of the gastrointestinal system
Development of the teeth
Development of the tongue
Development of the integumentary system
Development of the axial skeleton
Development of the limbs
Development of the muscular system
Development of the nervous system
Development of the renal system
Development of the reproductive system
Development of the respiratory system
0 / 15 complete
0 / 1 complete
The renal system starts developing during week 4 of intrauterine life.
At this point, the embryo is made up of three primitive germ layers: the ectoderm, the mesoderm and the endoderm.
The mesoderm also has three parts: the paraxial mesoderm, which flanks the embryo’s future vertebral column; the intermediate mesoderm, which is just lateral to the paraxial mesoderm; and the lateral plate mesoderm, which is the most lateral of all.
The intermediate mesoderm on either side of the embryo condenses to form a cylindrical structure called the urogenital ridge.
This ridge runs parallel to the embryo’s future vertebral column, and it gives rise to both the urinary and genital systems.
The portion of the urogenital ridge called the nephrogenic cord develops into the urinary structures.
Now, during the development of the urinary system, there are three sets of structures that emerge from the nephrogenic cord, and they form in a craniocaudal fashion—from head to tail-end.
The first structure to emerge from the nephrogenic cord is the pronephros, which appears in the neck region of the embryo at the beginning of week 4.
The pronephros consists of the pronephric duct and the nephrotomes in front of it.
The pronephric duct is basically a pipe that runs down the length of the nephrogenic cord, and the nephrotomes are small chunks of tissue that break off from the nephrogenic cord.
However, the pronephros doesn’t produce urine, and regresses by the end of week 4.
The renal system starts to form at about week 4 of gestation from a portion of the urogenital ridge called the nephrogenic cord. The nephrogenic cord gives rise to three overlapping developmental stages: the pronephros, the mesonephros, and the metanephros. Pronephros consists of an early and nonfunctional system, which regresses by week 4. Next is the mesonephros, which functions as a primitive excretory system in the embryo. Most tubules regress by week eight and are replaced by the metanephros. Metanephros give rise to actual kidneys, which appear at around week five, and become mature enough to secrete urine around week ten.
Latest on COVID-19
Nurse Practitioner (NP)
Physician Assistant (PA)
Create custom content
Raise the Line Podcast
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
Terms and Conditions
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.