SA : Vol Ratio

• Cells need to produce chemical energy (via metabolism) to survive and this requires the exchange of materials with the environment
• The rate of metabolism of a cell is a function of its mass / volume 
• The rate of material exchange is a function of its surface area
• larger cells need more energy to sustain essential functions
• large membrane surface equates to more material movement
• As a cell grows, volume increases faster than surface area, leading to a decreased SA:Vol ratio
• If metabolic rate exceeds the rate of exchange of vital materials and wastes, the cell will eventually die
• What tissues have adaptations that help optimize material transfer?

  Intestinal tissue of the digestive tract and alveoli within the lungs