circulatory systems and transport in animals Flashcards
whats an open circulatory system
-blood isn’t always held in the vessels
-blood fluid circulates through the blood cavity so tissues and cells become bathed directly in blood
whats a closed circulatory system
-blood stays entirely inside the vessels
-a separate fluid called tissue fluid called haemolymph bathes tissues and cells
open circulatory system advantages
-blood pressure is low and blood flow is low
-circulation of blood may be affected by body movements/lack thereof
advantages of closed circulatory system
-higher pressure so blood flows quicker
-more rapid delivery of o2 and nutrients, more rapid removal of co2 and waste products
-transport indapendent of body movements
what is a double circulatory system
-2 separate circuits, one carries blood to lungs to pick up o2 (pulmonary) and other carries oxygen and nutrients around the body to tissues where may be needed
what are the two parts of the double circulatory system
-lungs (pulmonary circulation)
-tissues where blood may be needed (systematic circulation)
advantages of double circulation
-efficient circulatory systems to deliver oxygen and nutrients quickly to parts of body where they’re needed
what can we compare to see the advantages of double circulatory
-fish and mamals
single circulatory system of fish
-blood pressure drops as blood passes through small capillaries of gills
-blood has low pressure as it flows through body and wont flow quickly
-rate at which o2 and nutrients are delivered to respiring tissues and co2/urea removed is limited
why is a single circulatory system sufficient in certain animals
-not as metabolically active and dont maintain body temp so dont need as much energy
double circulatory system of mammals
-blood pressure not too high in pulmonary circulation otherwise can damage capillaries of lungs
-heart can increase the pressure of blood after passing through the lungs
-blood is under high pressure as it flows through the body more quickly
-systematic circulation can carry blood at higher pressure than pulmonary circulation
what are the needs for a transport system
-all living animal cells need a supply of o2 and nutrients
-all living animal need to remove waste products so they dont build up to become toxic
why dont very small animals need a seperate transport system
-their cells are surrounded by or close to environment in which they live so diffusion will supply enough o2 and nutrients to survive
why cant larger animals rely on diffusion
-the diffusion distance is too long so diffusion will be too slow
3 main factors influencing need for transport systems
-Size
-SA:V ratio
-Level of metabolic activity
how does level of metabolic activity influence transport systems
-animals need more energy from food so releasing this energy by aerobic respiration which requires o2
-if animal is active, cells need good supply of nutrients for movement
what happens when heart relaxes in a open system
-the haemolymph is such back via ostia (pores)
