- Closed circulatory system: Blood is contained within vessels, which prevents direct contact with body tissues.
- Four-chambered heart: Two atria (upper chambers) and two ventricles (lower chambers) allow for efficient separation of oxygenated and deoxygenated blood.
- Systemic and pulmonary circuits: The circulatory system consists of two separate circuits: the systemic circuit, which supplies oxygenated blood to the body's organs and tissues, and the pulmonary circuit, which carries deoxygenated blood to the lungs for oxygenation.
- Arteries, capillaries, and veins: Arteries carry oxygenated blood away from the heart, capillaries allow for exchange of substances between blood and body tissues, and veins carry deoxygenated blood back to the heart.
- Cardiac cycle: The coordinated contraction and relaxation of the heart chambers, which results in the pumping of blood.
- Blood pressure: The force exerted by blood against the walls of blood vessels, which is regulated by various mechanisms to ensure adequate perfusion of tissues.
- Blood composition: Includes red blood cells (carry oxygen), white blood cells (involved in immunity), platelets (involved in blood clotting), and plasma (liquid component).
- Transport of oxygen, nutrients, and waste products: The circulatory system plays a vital role in delivering oxygen and nutrients to cells and removing waste products, including carbon dioxide.
Worm Circulatory System
- Open circulatory system: Blood is not entirely confined to vessels but flows through open spaces called sinuses or lacunae.
- Simple tubular heart or dorsal blood vessel: Earthworms have a simple tubular heart with segmental pulsating vessels, while flatworms have a dorsal blood vessel.
- Incomplete separation of oxygenated and deoxygenated blood: The circulatory system of worms does not have a complete separation of oxygenated and deoxygenated blood.
- Lack of capillaries: Worms do not have capillaries, and the exchange of substances between blood and tissues occurs directly from the open circulatory system.
- Blood composition: Includes coelomic fluid (similar to plasma), coelomocytes (cells analogous to white blood cells), and dissolved respiratory pigments like hemoglobin or chlorocruorin for oxygen transport.
- Transport of nutrients and waste products: The circulatory system of worms is primarily involved in the transport of nutrients absorbed from the digestive system to different parts of the body and in the removal of waste products.
