Respiration in Vertebrates

Surface area, perfusion , ventilation - skin, gills or lungs its all the same.

What is respiration?

• All large animals must have organs to exchange gases with the atmosphere. In the vertebrates there are three main organs.

• Skin

• Gills

• Lungs

What happens during respiration?• Gases move according to the diffusion

gradient. In the air around us or dissolved in water are relatively large amounts of oxygen and a small amount of carbon dioxide.

• Diffusion defined is: movement of molecules from an area of high concentration to an area of low concentration.

• Question 1 - what is the gradient?

• Question 2 - what causes the gradient?

Give a helping lung - or something• As you now know, oxygen diffuses into tissues

because the concentration in the tissues is less. The problem is that large animals cannot survive with only simple diffusion.

• How big is too big for diffusion? It depends….

The shark is too big! It can’t live without gills!

How gas exchanges works

• Gills, skin and lungs have many things in common. They all must be moist to function, they often have a large thin surface area and have a special blood supply.

• Ask yourself why these are requirements of a large animals respiratory system?

• Answers ……

Surface area tricks• All gas exchangers increase their effectiveness by

increasing their surface area. This often involves folds, wrinkles or sacs - anything that will increase area (but stay thin).

More tricks

Blood Flow• Blood flow to an organ of respiration can

greatly increase the amount of gases exchanged.

• Transporting away oxygen and bringing carbon dioxide to the gas exchanger.

Ventilation• Moving the air or water past the respiratory

structures greatly increases their effectiveness.

What is a good gas exchanger?• Large surface area, thin epithelium.

• Blood supplied to the area (best if it is deoxyenated)

• Ventilate the epithelium

• Keep the epithelium moist

Human Lungs

Human Alveoli

Gas Exchange

• Why is there carbon dioxide in respirators use to help people recover from respiratory distress?

• Why is it important that all gas exchange surfaces be moist?

• Which gas causes you to increase your breathing rate? Why - what acid is formed?

• Why is it important for runners to have high levels of carbonic anhydrase in their blood?

• Why is the mammalian respiratory system superior to that of reptiles and amphibians?