open and closed circulatory system Flashcards
(7 cards)
the open circulatory system is?
were the transportation fluid circulates freely in the body cavity, in which it bathes in cells.
substances then enter the cells via diffusion
o2 dissolves and diffuses into the fluid
what is haemolymph?
the fluid that transports substances such as gases around the body of an open circulatory system
what is the closed circulatory system
the fluid flows through enclosed vessels called arteries, veins and capillaries
the capillaries exchange gases and nutrients with interstitial fluid and body cells
waste products are moved to another system
what is the fluid used inside the closed circulatory system
Blood
name an animal with no circulatory system and explain why this is
Planaria
its simple structure such as the gastrovascular cavity can transport substances efficiently
having a gastrovascular cavity, a flat body along with the process of diffusion is enough to provide substances needed
compare the differences within open and closed systems (fluid, blood vessels, contact with cells, pathway of blood, pressure, body size, efficiency of blood flow)
Fluid Type
Open: Haemolymph
Closed: Blood
🔹 Blood Vessels
Open: Simple vessels release fluid into open body cavity
Closed: Arteries, veins, capillaries
🔹 Contact with Cells
Open: Direct – haemolymph bathes cells; direct exchange
Closed: Indirect – blood stays in vessels; substances diffuse via capillary walls
🔹 Blood Pathway
Open: Heart → body cavity → returns via ostia
Closed: Heart → lungs/body → back to heart through vessels
🔹 Pressure
Open: Low pressure (except arteries); less energy used
Closed: High pressure in arteries for fast delivery; more energy needed
🔹 Body Size Suitability
Open: Best for small animals with low energy needs
Closed: Best for large, active animals needing fast oxygen delivery
🔹 Efficiency
Open: Slow flow, limits metabolic rate and animal size
Closed: Fast, steady flow supports high metabolism and larger size
