What is the purpose of a subcutaneous injection?

The purpose of a subcutaneous injection is to deliver medication into the subcutaneous layer of tissue that lies just beneath the dermis of the skin. This method allows for the absorption of medication at a slower rate compared to intramuscular or intravenous injections, making it ideal for medications that require a gradual release into the bloodstream or for substances such as insulin or heparin.

Administering medication in this manner is effective because the subcutaneous tissue has a good blood supply, which facilitates the absorption process while still allowing for extended release. This technique is commonly used for vaccinations, certain hormone therapies, and other types of medications that do not require immediate systemic effects.

The other options refer to different injection methods or purposes, such as deep muscle delivery, direct bloodstream entry, or creating a skin response, which are not relevant to the function of subcutaneous injections.