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How does an insect’s open circulatory system move blood through its body?

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Illustration showing a variety of adult insects, each labeled with its common name and order, including walkingstick, earwig, stonefly, tree cricket, dragonfly, female scale, cat flea, thrips, sucking louse, thysanuran, ant, scarab beetle, stinkbug, mosquito, and cabbage butterfly, highlighting their diverse shapes and sizes. — insect An illustration of insect diversity.

Insects possess an open circulatory system in which the body fluid, known as hemolymph, circulates through the body cavity and appendages rather than being confined to a closed network of vessels.1

The primary mechanism for this movement is the dorsal vessel, a continuous tube extending from the abdomen through the thorax to the head. This vessel is divided into two main regions:1
* The Heart: Located in the abdomen, this pumping organ features paired lateral openings called ostia. When the heart relaxes, hemolymph flows into these chambers through the ostia.21
* The Aorta: This conducting vessel extends forward from the heart, carrying the hemolymph through the thorax and discharging it into the head.1

Once discharged, the hemolymph flows backward through the body cavities, or hemocoels, bathing the internal organs to transport nutrients and metabolic wastes. To ensure circulation reaches extremities like the legs, wings, and antennae, insects utilize accessory pumps before the fluid eventually returns to the abdomen to be recirculated.1