Respiration in Non-Homeotherms - Anatomy & Physiology

()Map CARDIORESPIRATORY SYSTEM (Map)

Fish

Fish live in a relatively dense and viscous fluid, which has little oxygen carrying capacity. In order to gain sufficient gaseous exchange for survival, fish have developed a highly efficient system which has a large surface area, and utilises energy - the gills.

Amphibia

In amphibian species, the skin forms the major, and sometimes only respiratory organ.

The skin of amphibia is:

• Thin
• Poorly keratinised
• Highly vascularised
• Moist to promote diffusion of gases

Aquatic amphibians may also have internal gills and Pharyngeal Slits.

Most Amphibia also have lungs for breathing. This contains interconnecting septa which divide the lumen into Faveoli, compartments which open into a central chamber within each lung.

Reptiles

Reptiles have a fundamentally different respiratory system to that of mammals, in that they lack a bronchial tree.

Route of Air in the Reptiliant Respiratory System:

1. Air enters via nares
2. Nasal Cavity
3. Choana
4. Glottis (base of tongue)
5. Trachea
6. Bronchi
7. Lungs

The lungs are paired, with respiration only occuring in the cranial region.

The Respiratory surface is composed of Faveoli, honeycomb shaped structures which line the walls.

Lizards

• No diaphragm