Ependymis (/ˌɛpɛnˈdɪmɪs/) is a medical term used to refer to the lining of the ventricles and central canal of the spinal cord. The word is derived from the Greek word "ependyma" meaning "a covering". The IPA phonetic transcription of the word reveals that the first syllable is pronounced as "epen" with the stress on the second syllable. The second syllable is pronounced as "dimis" with the stress on the first syllable. The spelling of the word is therefore based on its Greek roots and is pronounced accordingly.
The ependymis is a critical component of the central nervous system, playing a crucial role in the functioning of the brain and spinal cord. It is a thin, delicate layer of cells that lines the ventricles of the brain and the central canal of the spinal cord. Its primary function is to produce cerebrospinal fluid (CSF) and facilitate its circulation throughout the central nervous system.
Composed of ependymal cells interspersed with cilia and microvilli, the ependymis serves as a barrier between the cerebrospinal fluid and the surrounding nervous tissue. This specialized epithelial layer is responsible for the secretion of CSF, a clear, colorless fluid that provides cushioning and protection to the brain and spinal cord. Moreover, the ependymal cells possess cilia that help to promote the circulation of CSF, facilitating the exchange of nutrients and waste products within the central nervous system.
The ependymis also acts as a support structure, assisting in the maintenance and regulation of the chemical environment necessary for optimal neural function. Additionally, it participates in the formation of neural stem cells, which play a crucial role in neurogenesis and repair processes.
Pathological conditions affecting the ependymis, such as tumors or inflammation, can disrupt the production and circulation of CSF, leading to various neurological disorders including hydrocephalus. Therefore, understanding the structure and function of the ependymis is vital in the fields of neuroscience and neurosurgery.
The word "ependymis" is derived from the Greek word "ependyma", which means "upper garment" or "covering". In ancient Greek, "epi-" means "on" or "upon", and "endyma" refers to a cloak or a mantle. The term "ependymis" was originally used to describe a thin membrane-like covering in the human brain and spinal cord, which acts as a lining or barrier. Over time, the word has been adopted in the field of anatomy to refer to a type of tissue that lines the ventricles of the brain and the central canal of the spinal cord.