CO2 incubator is a primary essential instrument used in an animal cell culture laboratory. It is essential in creating a controlled environment. It creates a favourable physiological environment for the animal cells to grow in-vitro. Animal cells are highly sensitive and require precise temperature, humidity, and carbon dioxide levels to survive, grow, and function properly outside the body.

The CO2 incubator maintains adequate pH in the culture media. Cell culture media consist of a bicarbonate buffering system. This involves a series of chemical reactions. When CO2 in an incubator interacts with the medium it creates unstable carbonic acid. This quickly breaks into bicarbonate ions and hydrogen ions, which balance the pH.  This is crucial as pH fluctuation to too acidic or too alkaline makes the cells stressed. This triggers cells to produce unwanted cellular metabolites, and pushes towards unwanted apoptosis. The cells stop growing, or can even die.

Besides, the CO2 incubator enables temperature control. Most mammalian cells grow best at around 37°C. This is the average human body temperature. The incubator keeps this temperature constant to support healthier cellular activity and metabolism.

CO2 incubators maintain high humidity levels (95%). This prevents media evaporation from the culture vessels. An adequate amount of humidity is crucial to maintain adequate salt concentration and nutrient balance for the cells.

CO2 incubator creates a stable and sterile environment required for adequate animal cell culture growth in-vitro. It plays a critical role in research areas such as drug discovery, cancer biology, vaccine development, stem cell research, and regenerative medicine.

Endothelial cells and epithelial cells are distinct cell types that have precise functions in the body. Epithelial cells form the covering surfaces and lining cavities throughout the body. They form the skin (the largest tissue in the body), line organs like the stomach and lungs, and create protective barriers. Their main functions include protection, absorption, secretion, and filtration. For example, the epithelial lining of the intestine helps absorb nutrients, while the skin protects against external damage. These cells can be arranged in multiple layers and come in different shapes depending on their function.

Endothelial cells form the inner surface of the blood vessels. These cells are thin and have a single-cell layer called the endothelium. The primary role of the cells is to regulate tissue homeostasis and other fluids between the bloodstream and surrounding tissues. They also play a key role in controlling blood pressure, blood clotting, and inflammation.

In simple terms, all endothelial cells are epithelial in origin, but not all epithelial cells are endothelial. Epithelial cells have broader functions across different organs, while endothelial cells are specifically involved in vascular functions. Another key difference is structure—epithelial cells can be multilayered, whereas endothelial cells are always a single, thin layer to allow smooth blood flow.

Understanding this distinction is important, especially in medical and research fields, as both cell types are essential but serve very different purposes in maintaining overall body function.