Canaliculi are tiny channels or canals found in various bodily structures. Their function depends on their location.
Canaliculi in Bone
In bone tissue, canaliculi are microscopic canals connecting lacunae. Lacunae are small spaces within the bone matrix where osteocytes (bone cells) reside. These canaliculi form a complex network, allowing for nutrient and waste exchange between osteocytes and the blood supply. This intricate system ensures the health and survival of osteocytes deeply embedded within the bone.
- Nutrient Delivery: Canaliculi facilitate the transport of nutrients from blood vessels to osteocytes.
- Waste Removal: They also allow the removal of metabolic waste products from osteocytes.
- Communication: Canaliculi may also play a role in cell-to-cell communication within bone tissue.
The Wikipedia page on bone canaliculi provides further detail on their structure and function in the context of bone tissue. The SEER training website (https://training.seer.cancer.gov/anatomy/skeletal/tissue.html) also notes that canaliculi connect to adjacent cavities to receive blood supply, especially relevant in trabecular bone.
Canaliculi in the Eye
In the eye, canaliculi (singular: canaliculus) are small channels located near the inner corner of the eye. They are part of the tear drainage system, carrying tears from the eye to the nasolacrimal duct, which then drains into the nasal cavity. Inflammation of these channels is called canaliculitis. Information on this can be found at the Merck Manual (https://www.merckmanuals.com/home/eye-disorders/eyelid-and-tearing-disorders/canaliculitis) and Cleveland Clinic (https://my.clevelandclinic.org/health/diseases/24412-canaliculitis) websites.
Canaliculi in the Liver
In the liver, canaliculi are also found, specifically bile canaliculi. These tiny channels are formed between hepatocytes (liver cells) and function in the transport of bile from the liver. A recent study on inducing the formation of open-form bile canaliculi is available at Nature (https://www.nature.com/articles/s42003-023-05216-z).
In Summary
The term "canaliculus" refers to a small channel found in various organs and tissues. Its specific function depends on its location within the body. Understanding the context is vital when encountering this term.
