Is our heart a well-designed pump? The heart along animal evolution.
Level 5 - mechanism / opinion, no new human data
Narrative review of comparative anatomy and evolutionary biology without systematic methodology.
PubMed 24917644 · doi:10.1093/eurheartj/ehu222
What was done
This narrative review summarizes the evolutionary progression of circulatory pumping mechanisms across animal taxa (annelids, arthropods, mollusks, fishes, amphibians, reptiles, birds, and mammals) based on comparative anatomy and physiological adaptations to increasing metabolic rate.
What was found
Circulatory architecture evolved from open peristaltic tubes lacking capillaries in worms (blood pressure ~15 mmHg) to contractile aortic bulges with accessory hearts in arthropods, two-chambered hearts in mollusks and fish, three-chambered hearts with partial ventricular septation and variable shunting in reptiles, and completely separated four-chambered hearts in birds and mammals. Blood pressure progressively increases up to 170/70 mmHg in birds alongside rising metabolic rates. When systemic blood pressure exceeds 50 mmHg, animals develop a dedicated lower-pressure circuit through gills or lungs to optimize gas exchange, culminating in the complete structural separation of systemic and pulmonary circulations in four-chambered hearts.
Why it matters
It contextualizes human four-chambered cardiac anatomy within evolutionary physiology, highlighting how dual-circuit architecture resolved the biomechanical conflict between high-pressure systemic delivery and low-pressure pulmonary gas exchange.
Limits
The abstract describes a broad narrative synthesis rather than a systematic review. No formal search criteria, quantitative synthesis, or empirical functional fluid dynamics measurements are reported.
Cited by
- supports The human heart consists of four chambers, with two atria on the top and two ventricles on the bottom.