Unit 3 - Circulatory systems Flashcards
Define open circulatory system
a transport system with a heart but with few vessels to contain the transport medium
Define closed circulatory system
the transport medium is enclosed in vessels and does not come into contact with the cells of the body
Define haemolymph
the blood like fluid contained in insects
Give examples of organisms with a single closed circulatory system
Fish and annelid worms
Give examples of organisms with a double closed circulatory system
Birds and most mammals
Give an example of an organism with an open circulatory system
Insects
Why are single closed circulatory systems not very efficient?
Blood pressure drops considerably
so blood flows slowly back to the heart
Why are double closed circulatory systems very efficient?
-each circuit passes through only one capillary network
-this maintains relatively high blood pressure
-so fast flow of blood back to the heart is maintained
How are open and closed circulatory systems different?
-blood enclosed in vessels in closed but not in open
-in open circulatory systems the fluid fills body cavities
-open less efficient
What is an advantage of having an open circulatory system?
less vulnerable to pressure
What is an advantage of closed circulatory systems?
more efficient
What is a disadvantage of open circulatory systems?
requires low metabolic rate so does not work for larger animals
What is a disadvantage of closed circulatory systems?
requires more energy
