31.1: Introduction
We will be using Daphnia magna to explore basic principles of animal physiology. Daphnia is a genus of small crustaceans in the phylum Arthropoda. They are a good model organism for the study of animal physiology as we can see some organs and their functions under a microscope.
Figure \(\PageIndex{1}\): Female adult Daphnia magna with eggs. Attribution: " Female adult of the water flea Daphnia magna by Hajime Watanabe(opens in new window) " by dullhunk(opens in new window) is licensed under CC BY 2.0(opens in new window) .
Female adult Daphnia magna with eggs. Attribution: " Female adult of the water flea Daphnia magna by Hajime Watanabe(opens in new window) " by dullhunk(opens in new window) is licensed under CC BY 2.0(opens in new window) .
Among the organs visible in the Daphnia is the heart, located on the dorsal surface of the animals' body. Crustaceans, like other arthropods, have an open circulatory system , where the heart pumps blood into open sinuses throughout body. While the baseline heart rate is established by autorhythmic cells in the heart, it can be affected by a variety of environmental factors.