Hemolymph is a fluid found in the circulatory systems of arthropods and some mollusks. It serves a similar function to blood in vertebrates, transporting nutrients, hormones, and waste products throughout the body. Unlike blood, hemolymph is not contained within vessels; instead, it fills the body cavity, allowing for direct contact with tissues. This fluid also plays a crucial role in immune response and helps maintain pressure within the body, supporting movement and organ function. Hemolymph contains cells called hemocytes, which are involved in defense against pathogens and wound healing, making it essential for the survival of these organisms.