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  1. what is the primary controller of ventilation?
  2. what will happen generally when it is activated

  1. PaCO2
  2. Will increase tidal volume and increase respiratory rate


What are 2 other controllers of ventilation

  1. Increase in [H+]  in arterial blood or CSF causes increase in alveolar ventilation
  2. Decrease in PaO2 causes increase in alveolar ventilation


  1. what will you see in animals on examination during dyspnea or respiratory distress
  2. what can lead to it

  1. breathing appears difficult, uncomfortable, or labored
  2. Results from alterations in any part of the respiratory system
    • May be due to abnormal mechanics of the lung or chest wall


  1. what is cyanosis?
  2. what leads to it?

  1. Bluish or red-purple color in the mucous membranes
  2. Increased amount of deoxygenated Hemoglobin 3 to 5 g/dl of reduced Hemoglobin


  1. What will your SpO2 will show during cyanosis
  • PaO2?

  1. SaO2 or SpO2 of 73 to 78% (normal [Hb])
  2. PaO2 of 39 to 44 mmHg


will you see cyanosis in severe anemia?

may not show cyanosis


What is CRT

capillary refill time



  1. Eupnea-
  2. Tachypnea-
  3. Hyperpnea -
  4. Bradypnea-

  1. Eupnea- normal breathing
  2. Tachypnea- Increase in respiratory rate
  3. Hyperpnea - Increase in respiratory rate
  4. Bradypnea- Decrease in respiratory rate



  1. Hypocapnea- 
  2. Hypercapnea-
  3. Hypercarbia-

  1. Hypocapnea- Decrease in PCO2 concentration

  2. Hypercarbia-Increase in PCO2 concentration

  3. Hypercapnea- Increase in PCO2 concentration


what is being shown at 1?

  • Periodic Deep Breath = Sigh
  • Complimentary Breath


  1. What type of breathing pattern is this
  2. when will this commonly happen in


  1. Biot Breathing
    • Group Breathing
  2. common in anesthetized animals


  1. What is this called?
  2. what can cause this

  1. Kussmaul’s Breathing
    • Tidal volume will increase
  2. Metabolic Acidosis


  1. what is this breathing pattern called
  2. when will this generally happen

  1. Cheyne - Stokes Breathing
    • You will see a waxing and waning

    • Increase in tidal volume and then go back down

  2. Heart Failure
    • Poor feedback group of chemoreceptors back to brainstem


  1. What is the second breathing pattern called
  2. when can this happen

  1. Apneustic breathing
    • Will exhale first and then inhale

  2. Brain Stem Injury
    • Ketamine Anesthesia


what are 3 nonrespiratory functions of the respiratory system

1  Filter
2  Thermoregulation
3  Defense Mechanisms


Describe the 3 particle sizes, where they will be deposited in 

  1. >5 µm, large airways
  2. 1-5 µm, small airways


What is an aerosol?

small particles or liquid droplets suspended in air


List 2 or 3 toxic gases 

  1. carbon monoxide
  2. nitrogen oxides
  3. sulfur oxides



Which animals can do thermoregulation through nasal or mouth

  • Dogs
  • cats
  • sheep
  • birds


What happens during panting to allow animals to thermoregulate


  1. Rapid frequency (200-400 breaths/min)
  2. Small tidal volume
    • –Constant dead space ventilation (D)
    • –Small alveolar ventilation () avoids hyperventilation and alkalosis
  3. Vascular engorgement of respiratory and oral mucosa
  4. Increased salivation


What is the VD/VT ratio? 2. Why is the VD/VT ratio important for thermoregulation in the dog?

(this maybe on exam)

  • The VD/VT ratio is the fraction of each breath ventilating the dead-space area. 
  • Thermoregulation in the dog: when it is too hot the dog starts to pant and this has a smaller VT which increases water evaportaion and promotes heat loss to cool them off,
  • if they are too cold they slow down their respiration to preserve their heat and have a higher VT.


what is special about thermoregulation in even-towed ungulates (e.g thomson's gazell)


  • Nasal Evaporation 
  • Will be in circle of willis where it will cool blood going to brain.


What are 5 nonspecific defenses of the respiratory system


  1. Surfactant proteins A & D, defensin peptides
  2. Mucociliary system
  3. Cough
  4. Alveolar macrophages
  5. Toll-like receptors  - recognize bacteria/fungi


What is a specific defense of the respiratory tract

Immune system:  IgA in lining fluid


Explain the mucociliary system of the lung and include:  its function, where the mucus comes from, its distribution, how it’s moved cranially, and the value of the sol layer

  • Escalator to the pharynx (4 mm – 2 cm/min)
  • Cilia beat 1000x minute
  • Beat in coordinated manner
  • Sol layer – inner, liquid, low viscosity
  • Viscous gel layer – outer, catches particles
  • Blanket propelled by cilia and gravity
  • Mucus – nonciliate Clara cells, goblet cells, submucosal bronchial glands
  • Transepithelial movement of water and ions affects the thickness of the sol layer


  1. What does a cough accomplish?
  2. what stimulates it?
  3. How high of a pressure can it generate?

  1. Clears mucoid secretions from intrathoracic trachea and large bronchi
  2. Subepithelial irritant or stretch receptors
    • Mechanical deformation
    • Hyperresponsive when passages are inflamed
  3. 100 mmHg


Describe the function of the alveolar macrophage

  • Resident phagocyte in the normal lung
    • Mucociliary blanket
    • Traverse the alveolar wall and enters the lymphatic tissues
  • First line of defense
    • Produce bactericidal agents (lysozymes)
    • Phagocytosis- Engulf sediment