Comparative Respiratory Systems in Exotic Species

What are the limitations of the Ferret breathing system?

• Small nostrils

• Not obligate nasal breathers but prefer this route

• Tubes difficult so Oesophagostomy tube better (lots of tiny turbinate bones which can be damaged)

• Narrow Thoracic inlet so any abnormality can cause severe respiratory compromise (trachea, oesophagus, blood vessels etc)

How many lung lobes does a ferret have?

Left lung has two lobes → Cranial + Caudal

Right lung has four lobes → Cranial, Middle, Accessory + Caudal

Describe the limitations of the rodent Respiratory system

Obligate nasal breathing, they have long soft palates and a high larynx. Because rats have narrow nostrils and tight nasal passages, they are sensitive to airborne irritants like dust

How many lung lobes do rodents have?

Left lung → Single lobe

Right lung → Four lobes (cranial middle, caudal accessory)

Hamster may have an additional right lung

Describe the oxygen requirements of rodents and how they meet them

• Oxygen requirements are high

• Lungs are not larger relative to size but respiration is optimised

• Short airways and increased respiratory rates

• More alveoli of thinner diameter (increased SA)

• High chest wall compliance = increases vital capacity, decreases residual lung capacity

• Optimised to expand lungs and efficiently expel air

What is significant about the O2 binding curve in rodents?

Shifted to the right in smaller mammals, as Haemoglobin is more willing to exchange gases/releases oxygen more readily at tissue level. Lower affinity for oxygen so it is more readily unloaded to tissues that need it and CO2 can be removed just as quickly