2.1 (a-b) - Principles of Exchange and Transport + Plant Transport Flashcards
Define Surface Area
The total number of cells in direct contact with the environment
Define Volume
The 3-Dimensional space occupied by metabolically active tissues
The amount of material an organism needs to exhange is proportional to?
Volume of the organism
The amount of material an organism can exchange is proportional to?
Surface Area of the organism
What are the features of Exchange Surfaces which Aid Passive and Active Transport?
- Large Surface Area
- Thin Separating Surface
- Steep or Large Concentration Gradient
What is the benefit of having a Thin Separating Surface?
Increased Rate of Diffusion
What is the benefit of having a Steep Concentration Gradient?
Increased Rate of Diffusion
Describe the Adaptations of Erythrocytes (Red Blood Cells)
- Small Size
- Biconcave Disc Shape
- Thin Central Region of Disc
- No Organelles
What benefit to the function of an Erythrocyte is having a Small Size?
Reduces the Distance over which Oxygen has to Diffuse
What benefit to the function of an Erythrocyte is having a Biconcave Disc Shape?
Maximises the Surface Area of the cell without greatly affecting its Volume
What benefit to the function of an Erythrocyte is having a Thin Central Region of the Disc?
Allows the cell to distort its shape when it needs to squeeze through Capillaries, due to their lumens being slightly smaller than the diameter of the red cell
What benefit to the function of an Erythrocyte is having No Organelles?
Allows for more space for Haemoglobin on the red cell
Describe the Adaptations of the Capillary
- Wall of vessel is composed of only One Endothelial Cell
- The cell that makes up the wall of vessel is a Squamous Epithelial Cell
What benefit to the function of the Capillary is having a One Endothelial Cell thick wall?
Shortens the length of the diffusion pathway, making the Exchange of Gases by diffusion Faster
What benefit to the function of the Capillary is having Squamous Epithelial Cells (Flattened Cells)?
Ensures the length of the diffusion pathway is as short as possible
Describe the Adaptations of the Alveolus
- Collective Large Surface Area (>700 Million Alveoli)
- Walls of Alveoli are usually One Cell Thick
- Walls of Alveoli usually consist of Squamous Epithelial Cells
- Layer of Surfactant on Surface of Alveoli
What benefit to the function of the Alveoli is having a Collectively Large Surface Area?
Increases the amount of Gas Exchange Surface present
What benefit to the function of the Alveoli is having a One Endothelial Cell thick wall?
Shortens the length of the diffusion pathway, making the Exchange of Gases by diffusion Faster
What benefit to the function of the Alveoli is having Squamous Epithelial Cells (Flattened Cells)?
Ensures the length of the diffusion pathway is as short as possible
What benefit to the function of the Alveoli is having a Layer of Surfactant?
Helps to reduce Surface Tension and prevents Alveolar Collapse, which could greatly reduce the amount of Gas Exchange Surface area of the Alveolus
State Fick’s Law
Rate of Diffusion is proportional to
(Surface Area of Membrane X Difference in Concentration Across Membrane) / Thickness of Membrane
ROD α (SAD) / TOES
