Blood circulation of an arthropod

Answer 1

Arthropods do have circulatory fluid called hemolymph, containing nutrients to nourish the internal organs and cells. They have open circulatory systems, with the internal organs bathed in this fluid, in a body cavity called a hemocoel. Hemolymph differs from our blood in significant ways; in arthropods, there is no distinction between what we think of as blood and what we would consider lymphatic fluids. Also, for those arthropods that use hemolymph as the oxygen carrier, they don't use hemoglobin like our red iron-based blood; instead they use the copper-based hemocyanin. Hemocyanin is not bound to proteins on blood cells but floats freely around in the fluid. It is greyish in color but when oxygenated turns somewhat blue.

Insects don't use hemolymph to carry oxygen - they elimintate waste gas and oxygenate tissues directly from the air, drawn through a trachea into tubules from external holes (spiracles) in their body segments. Both this strategy and oxygenation using hemolymph is often assisted by the organism's movements.

Arthropods do have a kind of heart, a dorsal tube, which draws the fluid in from open ended pores in the hemocoel called ostia.

Answer 2

Arthropods do have circulatory fluid called hemolymph, containing nutrients to nourish the internal organs and cells. They have open circulatory systems, with the internal organs bathed in this fluid, in an internal body cavity called a hemocoel.

The fluid differs from our blood in significant ways; in arthropods, there is no distinction between what we think of as blood and what we would consider lymphatic fluids. Also, for those arthropods that use hemolymph as the oxygen carrier, they don't use hemoglobin like our red iron-based blood; instead they use the copper-based hemocyanin. Hemocyanin is not bound to proteins on blood cells but floats freely around in the fluid. It is greyish in color but when oxygenated turns somewhat blue.

Insects don't use hemolymph to carry oxygen - they elimintate waste gas and oxygenate tissues directly from the air, drawn through tubules connected to external holes (spiracles) in their body segments. For smaller organisms this works fine; both this strategy and oxygenation using hemolymph is often assisted by the organism's movements.

Answer 3

No, only echinoderms have one (starfish etc.).