Chapter 42 - Overview of Upper Airway function Flashcards
What is the maximal oxygen uptake (VO2max) for Thoroughbred and Standardbred racehorses?
160 mL/kg/min
By how much does the oxygen uptake in racehorses increase compared to the value at rest?
40 times
What is the approximate tidal volume (VT) at maximal exercise for a horse?
A) 10-12 L
B) 14-18 L
C) 8-10 L
D) 12-14 L
B) 14-18 L
What is the tidal volume at rest for a horse?
A) 10 L
B) 8 L
C) 5 L
D) 7 L
C) 5 L
What percentage of resistance to airflow is produced by the extrathoracic equine airway?
A) 50%
B) 60%
C) 70%
D) 80%
D) 80%
What is the respiratory frequency at maximal exercise?
A) 120 breaths/min
B) 100 breaths/min
C) 80 breaths/min
D) 140 breaths/min
A) 120 breaths/min
At exercise, the respiratory minute volume (VE) increases by how much?
A) 10-fold
B) 27-fold
C) 35-fold
D) 20-fold
B) 27-fold
What is the respiratory minute volume (VE) at rest for a horse?
A) 67 L/min
B) 70 L/min
C) 80 L/min
D) 65 L/min
A) 67 L/min
What is the peak inspiratory flow at rest?
A) 5 L/s
B) 4 L/s
C) 3.5 L/s
D) 2.5 L/s
C) 3.5 L/s
What is the peak inspiratory flow during exercise?
A) 55-65 L/s
B) 65-75 L/s
C) 45-55 L/s
D) 75-85 L/s
B) 65-75 L/s
What is the peak expiratory flow at rest?
A) 5.7 L/s
B) 6 L/s
C) 4.5 L/s
D) 3.7 L/s
A) 5.7 L/s
What is the peak expiratory flow during exercise?
A) 50-70 L/s
B) 55-75 L/s
C) 60-80 L/s
D) 45-65 L/s
C) 60-80 L/s
What is the peak inspiratory tracheal pressure at maximal exercise?
A) −10 to −20 mm Hg
B) −18 to −37 mm Hg
C) −15 to −30 mm Hg
D) −12 to −25 mm Hg
B) −18 to −37 mm Hg
What is the peak expiratory tracheal pressure at maximal exercise?
A) 6-20 mm Hg
B) 5-18 mm Hg
C) 8-25 mm Hg
D) 10-22 mm Hg
A) 6-20 mm Hg
At what gait are stride and respiratory frequency synchronized in a 1:1 ratio?
A) Walk
B) Trot
C) Canter
D) Gallop
C) Canter
How much resistance to airflow is produced by the nasal passages?
A) 12%-30%
B) 20%-50%
C) 26%-76%
D) 30%-60%
C) 26%-76%
What is the impedance of the upper airway during inspiration at exercise in normal adult horses?
A) 0.38-0.46 mm Hg/L/s
B) 0.5-0.6 mm Hg/L/s
C) 0.3-0.4 mm Hg/L/s
D) 0.4-0.5 mm Hg/L/s
A) 0.38-0.46 mm Hg/L/s
What is the impedance of the upper airway during expiration at exercise in normal adult horses?
A) 0.16-0.30 mm Hg/L/s
B) 0.20-0.40 mm Hg/L/s
C) 0.16-0.38 mm Hg/L/s
D) 0.30-0.50 mm Hg/L/s
C) 0.16-0.38 mm Hg/L/s
What percentage of resistance to airflow is produced by the larynx?
A) 15%-35%
B) 12%-30%
C) 10%-20%
D) 5%-15%
B) 12%-30%
What ratio is shorter, expiration or inspiration?
A) Expiration is shorter
B) Inspiration is shorter
C) They are equal
A) Expiration is shorter
What is the expiration to inspiration ratio (E
) during maximal exercise?
A) 0.9-1.0
B) 1.1-1.2
C) 0.96-0.99
D) 1.0-1.1
C) 0.96-0.99
What condition in horses causes an expiratory obstruction that increases expiratory impedance?
B) Dorsal displacement of the soft palate (DDSP)
According to the Bernoulli principle, what happens to pressure as airflow increases?
A) Pressure increases
B) Pressure decreases
C) Pressure remains constant
B) Pressure decreases
How much of the total airway resistance is produced by the upper airway during inspiration compared to expiration?
A) 1.5 times more
B) 2 times more
C) 1.2 times more
D) 3 times more
B) 2 times more
What law explains the relationship between airway diameter and airflow resistance?
A) Poiseuille’s Law
B) Boyle’s Law
C) Dalton’s Law
D) Venturi Effect
A) Poiseuille’s Law
What happens to inspiratory pressure as airway cross-section decreases?
A) Pressure increases
B) Pressure decreases
C) Pressure stays constant
A) Pressure increases
How much does the respiratory minute volume (VE) increase from rest to maximal exercise?
A) 10 times
B) 15 times
C) 20 times
D) 27 times
D) 27 times
What is the relationship between stride frequency and respiratory frequency at the canter and gallop?
A) 1:2 ratio
B) 1:1 ratio
C) 2:1 ratio
D) 1:3 ratio
B) 1:1 ratio
How much does respiratory frequency increase from rest to low speed (6 m/s)?
A) 10 times
B) 5 times
C) 8 times
D) 27 times
B) 5 times
At what speed does respiratory frequency cease to increase due to synchronization with stride frequency?
A) 5 m/s
B) 6 m/s
C) 7 m/s
D) 8 m/s
B) 6 m/s
At rest, how many liters per second is the airflow rate in horses during expiration?
A) 3.5 L/s
B) 4.5 L/s
C) 5.7 L/s
D) 6.0 L/s
C) 5.7 L/s
The Bernoulli principle is closely related to which effect?
A) Venturi Effect
B) Poiseuille’s Law
C) Boyle’s Law
D) Dalton’s Law
A) Venturi Effect
What is the driving force behind negative airway pressures in horses during maximal exercise?
A) Nasal dilation
B) Diaphragmatic contraction
C) Laryngeal contraction
D) Capacitance vessel constriction
B) Diaphragmatic contraction
What is the approximate percentage of resistance to airflow produced by the nose during inspiration?
A) 20%-40%
B) 26%-76%
C) 30%-50%
D) 15%-35%
B) 26%-76%
Peak inspiratory tracheal pressure in clinically normal horses at maximal exercise is between which two values?
A) −18 to −37 mm Hg
B) −10 to −25 mm Hg
C) −15 to −30 mm Hg
D) −20 to −40 mm Hg
A) −18 to −37 mm Hg
Peak expiratory tracheal pressure in clinically normal horses at maximal exercise ranges from:
A) 5 to 15 mm Hg
B) 6 to 20 mm Hg
C) 8 to 25 mm Hg
D) 10 to 30 mm Hg
B) 6 to 20 mm Hg
Which muscle is primarily involved in controlling negative pressures within the upper airway during maximal exercise?
A) Respiratory muscles
B) Diaphragm
C) Laryngeal muscles
D) Capacitance muscles
B) Diaphragm
What percentage increase in airflow resistance is produced by a narrowing of the airway lumen?
A) 2x
B) 4x
C) 8x
D) 10x
B) 4x
At maximal exercise, how much greater is the inspiratory upper airway impedance compared to expiratory impedance?
A) 2x greater
B) 1.5x greater
C) 3x greater
D) 4x greater
A) 2x greater
What percentage of total airway resistance is produced by the nasal passages at rest?
A) 50%-60%
B) 40%-50%
C) 26%-76%
D) 20%-30%
C) 26%-76%
What percentage of the sensory receptors within the laryngeal mucosa are pressure receptors in horses?
A) 40%
B) 50%
C) 60%
D) 70%
C) 60%
In Standardbred racing, how is the horse’s head and neck positioned?
A) Neutral
B) Flexed
C) Extended
D) Tilted
C) Extended
What anatomical structures are involved in the dynamic collapse of the laryngeal region?
A) Vocal folds, aryepiglottic folds, and arytenoid cartilages
B) Genioglossus and sternohyoid muscles
C) Nasal passages and trachea
D) External nares and nasal valve
A) Vocal folds, aryepiglottic folds, and arytenoid cartilages
By what percentage is the cross-sectional area of the larynx greater than that of the trachea?
A) 5%
B) 10%
C) 7%
D) 15%
C) 7%
What is the approximate percentage increase in upper airway impedance (ZI) when the horse’s head and neck are flexed?
A) 10%
B) 20%
C) 30%
D) 40%
C) 30%