Fish depend on specialized respiratory and circulatory systems to thrive in water. Their gills enable efficient oxygen uptake and carbon dioxide removal, while their heart and blood vessels form a single-loop circulatory system that ensures continuous transport of gases, nutrients, and waste products throughout the body.
Respiratory and circulatory systems in fish work together for gas exchange and transport, not storage or digestion.
Fish use gills for gas exchange, not lungs or intestines.
Fish have a single-loop circulatory system.
Fish gills exchange oxygen and carbon dioxide.
The single-loop matches blood flow with gill function but does not separate blood types.
Fish gills help regulate salt and water balance, not blood sugar or hormones.