Carotid Bodies

Fernando de Castro (1896–1967) was a pioneering Spanish neuroscientist best known for his groundbreaking work on the carotid bodies, which are small chemoreceptor organs located at the bifurcation of the carotid arteries. 

                                       

Discovery of Sensory Nature (1926–1928): Carotid Body 

De Castro was the first to demonstrate that the carotid body is a sensory organ, not merely a gland as previously believed. He studied the histological structure of the carotid body using advanced staining techniques and microscopy

                                                            Carotid Body: Sensory Organ 

                                             Located At The Bifurcation Of Carotid Arteries 

Cell Types in the Carotid Body

The carotid body is composed mainly of two types of cells:

Type 1 cells: Glomus cells:            

Chemoreceptors that detect changes in O₂, CO₂, and pH

Type II cells: Sustentacular cells

Glial-like support cells, modulate the activity of glomus cells

Innervation of the Carotid Body: He meticulously described the rich innervation of the carotid body by branches of the glossopharyngeal nerve (cranial nerve IX), suggesting its role in sensing changes in blood chemistry.'

Chemoreceptor Hypothesis: De Castro proposed that the carotid body functions as a chemoreceptor—sensing the chemical composition of the blood, especially oxygen levels—and that this information is transmitted to the brainstem to regulate respiratory activity

                                          

                                      Influence on Later Discoveries: 

His findings directly influenced Corneille Heymans, a Belgian physiologist who went on to win the Nobel Prize in Physiology or Medicine in 1938

Work demonstrating the reflexogenic role of the carotid bodies in respiration. 

Heymans himself acknowledged de Castro’s foundational work.

Snapshot 

Fernando de Castro (1926–1928): First to describe the carotid body as a sensory organ, richly innervated and capable of detecting oxygen levels in blood, forming the anatomical basis for modern respiratory physiology.