Final answer:
Histamine is released from mast cells and is responsible for increasing vascular permeability and mucous secretion, as part of the body's inflammatory response.
Step-by-step explanation:
The substance released from mast cells that increases vascular permeability and mucous secretion is histamine. During the inflammatory process, mast cells degranulate and release histamine which leads to an increase in the diameter of blood vessels (vasodilation) and increased permeability of capillaries. This results in the classic symptoms of swelling, redness, and itching associated with inflammation and allergic responses. These actions of histamine are a part of the body's defense mechanisms that aim to isolate and remove harmful agents and damaged tissue.
Histamine, released from mast cells, increases vascular permeability and mucous secretion. When mast cells are activated by tissue injury or an immune response, they release histamine, which causes vasodilation and increases blood flow. Histamine also increases the permeability of local capillaries, leading to plasma leakage and swelling. This inflammatory response is part of the body's defense mechanism against injury or infection.