Examples of specialized gaseous exchange surfaces

The specialized gaseous exchange surfaces provide large surface area by developing flaps, sac or tubes.  

1. Body surface is usually sufficient gaseous exchange surface for small animals such as protozoa, earthworm, flatworms with larges surface-volume ratio.

2.  Aquatic organism such as lungworm and tadpole use external gill which are epidermal outgrowths from the surface of the body

3. Fish use internal gills which are enclosed within the body and protected from damage.

4. Air-breathing vertebrate have developed lung where air is brought close to blood to allow gaseous exchange

The biggest problem of gaseous exchange through by the lung is that energy is required for ventilation especially during inspiration and leads to water loss. 5. insects have developed a tracheal system penetrating and ramifying and delivering oxygen to tissue cell 6. The frog and other amphibians use the skin and buccal cavity in addition to lungs Gaseous exchange in arthropods.

Gas exchange in insects takes place through the trachea, the air tubes, which terminally branch in tracheoles. Each tracheole delivers oxygen and removes carbon dioxide from each cell. Air enters and leaves the tracheal system through the spiracles. Some insects can ventilate the tracheal system with body movements. The gaseous exchange then occurs directly between the air in the tracheoles and the tissues and blood is not required to carry the gases. Tracheoles lack chitin moreover the degree of their branching may be adjusted according to metabolic needs of individual tissues. In some insects such as grasshopper are ventilated by rhythmic movements of the thorax and abdomen and in all flying insects, ventilation is aided by muscular movement during flight. Please find free downloadable notes, exams and marking guides of agriculture, biology, Physics, chemistry etc.  from digitalteachers.co.ug website. Dr. Bbosa Science