Toad ‒ Anatomy

Frogs are ectothermic animals, meaning they rely on environmental heat to regulate their body temperature. They have a closed circulatory system with a three-chambered heart, consisting of two atria and one ventricle. Blood flowing through the heart in both pulmonary and systemic circulations maintains approximately the same oxygen concentration. This consistency occurs because frogs use multiple methods of respiration: in addition to lungs, they exchange gases through their skin (cutaneous respiration) and the buccopharyngeal (throat) region. Cutaneous respiration can take place on land or in water, allowing frogs to thrive in both environments. Buccopharyngeal respiration is responsible for 1 to 7% of total gas exchange. However, both cutaneous and buccopharyngeal respiration are less efficient than lung-based respiration, as they are continuous processes that do not adjust with changes in metabolic demand. The frog's brain has three subdivisions: the forebrain, midbrain and hindbrain. The forebrain regulates visceral functions, the midbrain processes sensory information, and the hindbrain controls essential functions such as heart rate and respiration mechanisms.