In this section, you will explore the following questions:
- How do vacuoles, present in microorganisms, work to excrete waste?
- How do flame cells and nephridia in worms perform excretory functions and maintain osmotic balance?
- How do insects use Malpighian tubules to excrete wastes and maintain osmotic balance?
Connection for AP® Courses
The information in this section is not within the scope for AP® other than to appreciate that other organisms, including microorganisms and invertebrate animals, use more primitive and simple mechanisms to get rid of metabolic waste and maintain osmotic balance. For example, contractile vacuoles are common in microorganisms; flame cells and nephridia in certain species and worms, and Malpighian tubules in insects are other examples of excretory systems. Osmoregulation is vital for all organisms to maintain homeostasis.
Information presented and examples highlighted in this section are not within the scope for AP® and do not align to the Curriculum Framework.
Contractile Vacuoles in Microorganisms
Flame Cells of Planaria and Nephridia of Worms
Malpighian Tubules of Insects
Visit this site to see a dissected cockroach, including a close-up look at its Malpighian tubules.
- Malpighian tubules are the tubules within a nephron in humans.
- Malpighian tubules are the opening of the digestive sac in box jellyfish.
- Malpighian tubules are organs that filter waste from hemolymph in cockroaches.
- Malpighian tubules are tiny, bulb-shaped organs that open to an excretory pore in leeches.