1.1.1 - The Need For A Circulatory System Flashcards
What Do The Cells Of All Living Organisms Need A Constant Supply Of?
Reactants for metabolism. E.g. Glucose and oxygen.
How Do Single Celled Organisms Gain Oxygen & Glucose?
Directly from their surroundings and the molecules can diffuse to all parts of the cell quickly due to a short diffusion distance.
How Do Larger (Multicellular) Organisms Gain Oxygen & Glucose?
(4 Points)
~ They are made up of many layers of cells.
~ The time taken for substances to diffuse to every cell in the body would be too long.
~ Larger organisms have higher diffusion distances and energy requirements, this means the delivery of reactants for metabolism needs to happen quickly.
~ To solve this problem their exchange surfaces are connected to a mass transport system.
Describe Mass Transport Systems
(2 Points)
~ Used to carry raw materials from specialised exchange organs to the body cells and to remove metabolic waste.
~ E.g. Circulatory system.
What Do Mass Transport Systems Help To Do?
(3 Points)
~ Bring substances quickly from one exchange site to another.
~ Maintain diffusion gradients at exchange sites, between cells and their fluid surroundings.
~ Ensure effective cell activity by supplying reactants and removing waste products.