ANSWERS

1. Define respiration.
   The gaseous exchange between a living structure (plant or animal) and its environment.
2. What is the difference between internal and external respiration?
   Internal respiration is the gaseous exchange between the blood and the tissues, whilst external respiration is the gaseous exchange between the air and the blood.
3. By what other name may internal respiration be known?
   Tissue respiration.
4. How much oxygen is present in inspired air?
   21%.
5. How much oxygen is present in expired air?
   16%.
6. How much carbon dioxide is present in inspired air?
   0.04%.
7. How much carbon dioxide is present in expired air?
   4-5%.
8. What is the name of the most prevalent gas present in air?
   Nitrogen (79% in both inspired and expired air).
9. List the components of the respiratory system.
   • Nose and nasal chamber.
   • Pharynx.
   • Larynx.
   • Trachea.
   • Bronchi.
   • Bronchioles.
   • Alveolar ducts and alveoli.
10. What is another name given to the nostrils?
    External nares (the internal or posterior nares are where air enters the pharynx).
11. What is the name of the cartilaginous structure that divides the nasal chamber into two?
    The nasal septum.
12. Name the bones found within the nasal chamber and state their function.
    Naso turbinate bones; these are covered with ciliated mucous membrane and serve to moisten, warm and filter air passing over them prior to entry to the lower respiratory tract.
13. What is the name given to the area at the back of the mouth used by both the respiratory and digestive tracts?
    The pharynx.
14. There are several openings into the pharynx; can you list them?
    • Nasal chamber.
    • Mouth.
    • 2 Eustachian tubes (from the middle ear).
    • Oesophagus.
    • Larynx.
15. What is the purpose of the paranasal sinuses found in the skulls of large herbivores?
    Lightening the weight of an otherwise very heavy skull.
    NB. Sinuses are air-filled cavities within a bone.
16. State the 2 functions of the larynx.
    • Entrance to lower respiratory tract.
    • Sound production.
17. What is the name of the structure that attaches the larynx to the skull and allows it to move back and forth like a swing?
    The hyoid apparatus.
18. What is the name of the opening sited at the front of the larynx?
    The glottis.
19. The epiglottis is responsible for closing the glottis during swallowing. What is the epiglottis made of?
    Elastic cartilage.
20. Which of the following are the vocal cords: ligaments, tendons or muscles?
    Ligaments.
21. What is the correct name for the windpipe?
    The trachea.
22. Describe the structure of the trachea.
    Comprises incomplete rings of hyaline cartilage separated by fibrous connective tissue and smooth muscle fibres. It is lined with ciliated mucous epithelium.
23. How many lung lobes does the dog possess?
    3 In the left and 4 in the right.
24. What is the name of the lobe present in the right lung lobe but not in the left?
    The accessory lobe.
25. State the names of the lobes of the left lung.
    • Cranial (apical).
    • Middle (cardiac).
    • Caudal (diaphragmatic).
26. What is the function of the alveoli?
    They are the site where gaseous exchange takes place.
27. In which of the body cavities are the lungs located?
    The thoracic cavity.
28. State the main muscles involved in inspiration.
    • The external intercostals.
    • The diaphragm.
29. What is the name of the nerve that runs through the diaphragm?
    The phrenic nerve.
30. Expiration is generally passive and is caused by the relaxation of the external intercostals and diaphragm; which muscles are involved in cases of forced respiration?
    • The internal intercostals.
    • The abdominal muscles.
31. What are stretch receptors and where would you find them?
    These are responsible for informing the respiratory centres in the brain of the degree of inflation of the bronchial tree. They are located in the walls of the bronchioles.
32. What is the name of the reflex that controls the degree of inflation of the bronchial tree?
    Hering-Breuer reflex.
33. What is Cheyne-Stokes reaction?
    The respiration that often occurs shortly before death, and is characterised by alternating periods of deep, rapid and shallow breathing.
34. State the normal respiratory rate range in cats and dogs.
    • Cats - 20-30 breaths per minute.
    • Dogs - 10-30 breaths per minute (depending on size, smaller dogs have a faster respiratory rate).
35. Why do miniature breeds of dog, puppies and kittens have a higher respiratory rate?
    Smaller animals have a higher metabolic rate and therefore require a greater oxygen intake. Subsequently, their respiratory rate is higher.
36. State the pH of the blood. Why is this an important parameter in the subject of respiration?
    7.35. The pH of the blood is an important consideration in this subject since the rate of respiration is controlled by centres in the medulla that monitor this factor. If respiration is too slow or too shallow, carbon dioxide builds up in the blood and the respiratory pacemaker responds by increasing the rate and depth of respiration to remove surplus C02 and restore the blood pH to the correct level.
37. What is the function of the aortic and carotid bodies?
    These respond to changes in oxygen and C02 levels in the blood and influence the medullary respiratory centre accordingly.
38. What is meant by tidal volume?
    The amount of air breathed in and out during one quiet respiration.
39. What is the name given to the extra air drawn into the lungs during a forced intake of breath?
    Inspiratory reserve volume.
40. What is the inspiratory capacity?
    Tidal volume plus inspiratory reserve volume.
41. What is the name of the air left in the lungs following expiration?
    Residual volume.
42. List 5 factors that may affect the vital capacity of the lungs (this is the total volume of the respiratory tract that can be used during respiration).
    • Fullness of the stomach.
    • Presence of an intra-abdominal mass.
    • Gravid uterus.
    • Position of the animal (standing or lying).
    • Pulmonary oedema.
43. What is the name given to the volume of air drawn in at each respiration that never reaches the alveoli?
    Dead space.
44. Give an example of increased functional dead space detrimental during general anaesthesia.
    The use of an overly long endotracheal tube.
45. Define the following: apnoea, dyspnoea, bradypnoea, tachypnoea and hyperpnoea.
    • Apnoea - cessation of breathing.
    • Dyspnoea - difficulty breathing.
    • Bradypnoea - a slower than normal respiratory rate.
    • Tachypnoea - a faster than normal respiratory rate.
    • Hyperpnoea - panting.
46. Define the following: hypoxia, asphyxia.
    • Hypoxia - inadequate oxygenation of the brain.
    • Asphyxia - a deficiency of oxygen in the blood.
47. Give 4 examples of possible causes of dyspnoea.
    • Fluid in the alveolar spaces as a result of irritant smoke inhalation after a fire.
    • Collapsed lungs as a result of a ruptured diaphragm.
    • Hypoxia as a result of carbon monoxide poisoning.
    • Obstructed upper airway as a result of a pharyngeal foreign body.
48. List the 4 most important considerations in the nursing of a dyspnoeic patient.
    • Close observation of the vital signs (pulse rate and depth, respiratory rate and depth, temperature, mucous membrane colour).
    • Rest.
    • Gentle/minimal handling in a calm and quiet environment.
    • Provision of oxygen if necessary.