Increasing Surface Area : Volume
- It is crucial to maximise surface area to volume ratio in cells which require movement of substances across the membrane
- The larger the surface area compared to the volume of the cell, the faster the rate of substance movement
Red blood cells
- The function of a red blood cell (also known as an erythrocyte) is to deliver oxygen from the lungs to respiring cells
- They are flattened and biconcave shaped in order to maximise the surface area and minimise volume
- This means that oxygen can diffuse into the red blood cell more quickly in the lungs and out again at the respiring tissues
Adaptations of a Red Blood Cell Diagram
The biconcave shape and flattening of erythrocytes increases the surface area available for oxygen absorption
Proximal convoluted tubule cells
- The proximal convoluted tubules are tiny tubes found in the outer region of the kidney
- The tubules are responsible for reabsorption of vital substances e.g. glucose and mineral ions from the glomerular filtrate
- There are several adaptations to maximise surface area in the proximal convoluted tubule cells to ensure that the body reabsorb all the necessary substances
- Microvilli - in the apical membrane
- Invaginations - infoldings found in the basal membrane
Proximal Convoluted Tubule Cell Adaptations Diagram
The cells of the proximal convoluted tubule cells have invaginations and microvilli to increase surface area