Circulatory System Flashcards
Compare the open and closed circulatory systems
- In an open system, hemolymph directly bathes tissues for exchange, while in a closed system, blood stays in vessels and exchanges occur via diffusion across capillaries.
What is an example of an organism with an open circulatory system?
Arthropods
- Insects
- Crustaceans
What are examples of organisms with a closed circulatory system?
Chordates, Annelida, Cnidaria
- Birds
- Mammals
- Worms
- Jellyfish
What is an open circulatory system?
A system where blood is not confined to blood vessels and flows freely through body cavities, directly bathing organs and tissues.
What is a closed circulatory system?
A system where blood is confined to vessels, creating a separation between blood and interstitial fluid, allowing for more efficient transport of substances.
How does blood flow in an open circulatory system?
Blood (or hemolymph) is pumped from the heart into body cavities (hemocoel), where it directly surrounds the organs and returns to the heart.
How does blood flow through the circulatory system of fish?
Blood is pumped from the heart to the gills for oxygenation, then directly to the rest of the body (single circulation).
What is a limitation of the fish circulatory system?
Blood pressure drops significantly after passing through the gills, leading to a slower flow to the rest of the body.
How does blood flow through an amphibian’s heart?
Blood from the lungs and skin returns to one atrium, while deoxygenated blood from the body returns to the other atrium. Both types mix in the single ventricle before being pumped to the body and lungs.
What is a key disadvantage of the amphibian heart?
Mixing of oxygenated and deoxygenated blood in the single ventricle reduces the efficiency of oxygen transport.
How many chambers does an amphibian heart have?
3
How does double circulation work in birds and mammals?
Blood is pumped from the heart to the lungs for oxygenation (pulmonary circulation) and then back to the heart before being pumped to the rest of the body (systemic circulation).
How many chambers does a fish have?
2
Why is the four-chambered heart more efficient for endotherms like birds and mammals?
It allows for higher metabolic rates by maximizing oxygen delivery and preventing the mixing of oxygenated and deoxygenated blood.
