Related Experiment Video
Updated: Feb 9, 2026

Optical Sectioning and Visualization of the Intervertebral Disc from Embryonic Development to Degeneration
Published on: July 8, 2021
The origin, development, and degeneration of the pronephros in Caretta caretta
1Human Morphology, University of Southampton, Medical and Biological Sciences Building, Bassett Crescent East, Southampton SO93TU, United Kingdom.
Abstract:
An SEM and TEM study revealed details of the development of the pronephros of Caretta caretta. The pronephros develops and degenerates over 13 days from day 7 to day 20 in embryos incubated at 33°C. Podocytes, with primary branches, secondary branches, and pedicles, on a basal lamina, can be seen from day 11, as can ciliated pronephric tubule ostia opening into the coelom. At this stage the embryo has four pharyngeal arches with unfused mandibular processes, and small fore-limb buds each with an apical ectodermal ridge. Maturation of the pronephros occurs between days 15 and 17. Degeneration begins around day 18 and is advanced by day 20 when the embryo has a fully developed face, fore-limbs with digits, and the carapace and plastron have formed.
Related Concept Videos
Cancers Originate from Somatic Mutations in a Single Cell
Sustainable Development
Language Development
The critical period for language acquisition suggests that the ability to acquire language is at its peak early in life. As people age, this proficiency decreases. Language development begins very...
Development of the Lymphatic System
The first lymph sacs to form are the paired jugular lymph sacs located at the junction of the internal jugular and subclavian veins. From these sacs, lymphatic capillary plexuses extend to the thorax, upper limbs, neck, and head, eventually forming lymphatic vessels. Each jugular lymph sac maintains a...
Development of Immunocompetence
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...
Development of the Heart
As the embryo undergoes lateral folding, these paired tubes approach each other, merging into a single primitive heart...

