Final answer:
Plasma cells are responsible for the secretion of immunoglobulins, or antibodies, in the immune system.
Step-by-step explanation:
The cell type responsible for the secretion of immunoglobulins is the Plasma cell. Plasma cells are a type of B cell that has differentiated in response to antigen binding, and they have the ability to secrete soluble antibodies. They play a crucial role in the humoral immune response by producing and releasing immunoglobulins, or antibodies, into the bloodstream.