How many chambers does a rat's heart have? - briefly
A rat possesses a four‑chambered heart, consisting of two atria and two ventricles. This structure aligns with the typical mammalian cardiac organization.
How many chambers does a rat's heart have? - in detail
The mammalian rodent heart is composed of four distinct chambers: a right atrium, a left atrium, a right ventricle, and a left ventricle. Each chamber participates in a specific phase of the cardiac cycle, ensuring separation of oxygen‑poor and oxygen‑rich blood.
- Right atrium – receives deoxygenated blood from the systemic veins and channels it to the right ventricle.
- Left atrium – collects oxygenated blood from the pulmonary veins and delivers it to the left ventricle.
- Right ventricle – pumps blood into the pulmonary artery for gas exchange in the lungs.
- Left ventricle – propels oxygen‑rich blood into the aorta to supply the body.
The atrial walls are relatively thin, reflecting the low pressure required for venous return. In contrast, the left ventricular myocardium is markedly thicker than the right, accommodating the higher systemic arterial pressure. Typical left‑ventricular wall thickness in adult rats ranges from 1.5 mm to 2.0 mm, whereas the right‑ventricular wall measures approximately 0.8 mm.
Heart rate in rodents exceeds that of larger mammals, often reaching 300–400 beats per minute at rest. Despite the rapid rhythm, the four‑chamber architecture preserves the same sequential filling and ejection pattern observed in humans, making the rat an established model for studying cardiac physiology, pharmacology, and disease mechanisms.