Exchange Surfaces

Why do larger, multicellular organisms need a transport system?

• Smaller SA:V ratio

• Larger oxygen and metabolic demand

• Longer diffusion distance, won’t be able to meet up with demands

Name all the features of the TRACHEA that make it efficient for breathing

• Cartilage rings - hold the airway open

• Ciliated epithelial tissue - wafts particles away from the lungs

• Goblet cells - secretes mucus to trap particles/pathogens

Name all the features of the BRONCHIOLES

• Bits of cartilage (very small bits)

• Ciliated epithelial tissue

• Goblet cells

Name all features of ALVEOLI

• Large surface area - more area for gas exchange to occur

• Good blood supply - this maintains the concentration gradient

• Good ventilation - maintains concentration gradient

• Surfactant - keeps alveoli humid so more air can come in

Name the features of the respiratory system of a fish

• Countercurrent system - maintains the concentration gradient

• Gill lamellae and secondary lamellae - increased surface area for diffusion

What are the rings in a spiracle made from

Chitin

Shape of cartilage rings in humans, and why?

C-shape - Gives room for the oesophagus

Pathway of air/water in a fish’s system

1) Buccal cavity opens, and water goes through

2) Buccal cavity closes, forcing air through the gills

3) After gas exchange, water is pushed through the operculum