Ch.42 Overview of Upper Airway Function

Question 1

Which of the following statements is correct

a. At maximal exertion, Thoroughbred and Standardbred racehorses have a maximal oxygen uptake (VO2max) of approximately 160mL/kg/min.

b. At maximal exertion, Thoroughbred and Standardbred racehorses have a maximal oxygen uptake (VO2max) which is 20 times the value at rest.

c. At maximal exertion, Thoroughbred and Standardbred racehorses have a maximal oxygen uptake (VO2max) of approximately 40mL/kg/min.

d. At maximal exertion, Thoroughbred and Standardbred racehorses have a maximal oxygen uptake (VO2max) which is 10 times the value at rest.

Answer 1

a. At maximal exertion, Thoroughbred and Standardbred racehorses have a maximal oxygen uptake (VO2max) of approximately 160mL/kg/min. which is 4o times the value at rest

Question 2

Respiratory volume of horse at rest

Answer 2

67L/min

Question 3

Respiratory volume of horse at exercise

Answer 3

1800L/min

Question 4

Tidal volume of horse at rest and at exercise

Answer 4

5L
14 - 18L

Question 5

Expiration:Inspiration ratio

Answer 5

0.96:0.99

Question 6

Peak inspiratory flow at rest and at exercise

Answer 6

3.5L/sec
65-75L/sec

Question 7

Peak inspiratory and expiratory tracheal pressure

Answer 7

-18 - -37mmHg
6 - 20mmHg

Question 8

Venturi effect

Answer 8

Increase in flow such as air results in a pressure drop

Question 9

Extrathoracic resistance to inspiration or expiration is higher

Answer 9

Inspiration - double that of expiration

Question 10

Inspiratory and expiratory impedance

Answer 10

Insp 0.38-0.46 mmHg
Exp 0.16-0.38 mmHg

Question 11

Where does the greatest drop in airway pressure occurs

Answer 11

Nostril

Question 12

The cross section of the larynx is how much larger than that of the trachea

Answer 12

7%

Question 13

What are the pressure receptors in the larynx innervated by

Answer 13

Internal branch of the cranial laryngeal nerve (runs through thyroid notch)

Question 14

Negative pressure within the upper airway increases the activity of what mm

Answer 14

Genioglossus
Dorsal cricoarytenoid
Cricothyroid
Nasolabial
Sternothyroid
Sternohyoid

When large collapsing pressures are produced in the upper airway - contract - resist dynamic collapse

Question 15

What is the narrowest point of the upper respiratory tract

Answer 15

Nasal valve

Question 16

Dilator mm of the external nares

Answer 16

M. dilator naris lateralis
M. transversus nasi

innervated by the facial nerve

Question 17

How does Horner’s syndrome affect airflow

Answer 17

Disruption of the sympathetic trunk which interferes with the sympathetic tone of the capacitance vessels of the turbinate region resulting in vascular engorgement and occlusion of the nasal passage

Question 18

Bones of the hyoid apparatus

Answer 18

Paired;
1. stylohyoid x2
2. ceratohyoid x2
3. Thyrohyoid. x2

and centred ;
basihyoid. x1

Question 19

Rostral hyoid mm

Answer 19

1. Hyoglossus
2. Styloglossus
3. Genioglossus
4. Geniohyoideus

Innervated buy the hypoglossal n.

Question 20

Attachments of rostral hyoid mm

Answer 20

Hyoglossus - Basi & Thyro
Styloglossus - Stylohyoid
Genioglossus - Basi & Cerato
Geniohyoideus - Ling process of basi

Question 21

Action of the thyrohyoideus m

Answer 21

Innervated by the hypoglossal n
Draws larynx rostrally and dorsally
Draws root of tongue caudally by its attachments to the thyrohyoid and basihyoid bones

Question 22

Action of the Genioglossus and geniohyoideus mm

Answer 22

Pull larynx rostrally and ventrally

Question 23

Action of the sternothyroideus and sternohyoideus mm

Answer 23

Pull larynx caudaoventrally

Question 24

What m supports the dorsal pharyngeal wall

Answer 24

Stylopharyngeus mm

Question 25

Contraction of the Stylopharyngeus mm results in what

Answer 25

Raises the wall of the dorsal nasopharynx expanding, supporting and preventing its collapse

Question 26

Which of the following statements is correct

a. To provide an increase in VO2max minute ventilation, respiratory frequency increases significantly whilst tidal volume stays the same

b.The high airflow rates required to meet the racehorse’s ventilatory demand are created by diaphragmatic contraction, which produces strong negative airway pressures within the upper airway.

c. The high airflow rates required to meet the racehorse’s ventilatory demand are created by diaphragmatic contraction, which produces strong positive airway pressures within the upper airway.

d. To provide an increase in VO2max minute ventilation, tidal volume significantly increases whilst respiratory frequency stays the same

Answer 26

b.The high airflow rates required to meet the racehorse’s ventilatory demand are created by diaphragmatic contraction, which produces strong negative airway pressures within the upper airway.

To provide an increase in minute ventilation, tidal volume and respiratory frequency both increase significantly.

Question 27

Which of the following statements is correct

a. At a walk and trot, respiratory frequency is related to stride frequency

b. locomotory forces are the primary determinants of breathing during exercise

c. Respiratory minute volume (VE) in horses is approximately 27 L/ min at rest, rising 67-fold to 1800 L/min at exercise

d. At low speeds of up to 6m/s respiratory frequency rises from 14breaths per minute to 120breaths per minute

Answer 27

d. At low speeds respiratory frequency rises from 14breaths per minute to 120breaths per minute

At a walk and trot, respiratory frequency is not related to stride frequency

locomotory forces are not the primary determinants of breathing during exercise

Respiratory minute volume (VE) in horses is approximately 67 L/ min at rest, rising 27-fold to 1800 L/min at exercise

Question 28

Which of the following statements is correct

a. VT is approximately 5 L at rest and it increases to 30 to 40 L at maximal exercise

b. Peak inspiratory flow at rest is approximately 10 L/s and this rises dramatically at exercise to 100 L/s

c. Peak inspiratory tracheal pressure has been reported as −18 to −37 mm Hg for clinically normal horses at maximal exercise

d. Peak expiratory tracheal pressure has been reported as -6 to -20 mm Hg for clinically normal horses at maximal exercise

Answer 28

c. Peak inspiratory tracheal pressure has been reported as −18 to −37 mm Hg for clinically normal horses at maximal exercise

VT is approximately 5 L at rest and it increases to 14 to 18 L at maximal exercise

Peak inspiratory flow at rest is approximately 3.5 L/s and this rises dramatically at exercise to 65 to 75 L/s

Peak expiratory tracheal pressure has been reported as 6 to 20 mm Hg for clinically normal horses at maximal exercise

Question 29

Which of the following statements is correct

a. A localized rise in airway pressure occurs over the vocal cords and contralateral aryepiglottic fold in the presence of partial arytenoid abduction

b. Up to 80% of resistance to airflow is produced by the extra- thoracic equine airway both at rest and during exercise.

c. The larynx (26%–76%), followed by the nasal passages(12%–30%), produce the greatest resistance to flow within the upper airway

d. High tracheal flow rates and the complex geometry of the upper respiratory tract mean that tracheal flow in the horse is always laminar

Answer 29

b. Up to 80% of resistance to airflow is produced by the extra- thoracic equine airway both at rest and during exercise.

A localized drop in airway pressure occurs over the vocal cords and contralateral aryepiglottic fold in the presence of partial arytenoid abduction

The nasal passages (26%–76%), followed by the larynx (12%–30%), produce the greatest resistance to flow within the upper airway

High tracheal flow rates and the complex geometry of the upper respiratory tract mean that tracheal flow in the horse is always turbulent

Question 30

Which of the following statements is true regarding the upper airway

a. the cross-sectional area of the larynx is approximately 7% smaller than the trachea

b. flexed head and neck position significantly decreases ZI (inspiratory impedence)

c. greatest drops in airway pressure occur at the larynx

d. None of the above

Answer 30

d. None of the above

a. the cross-sectional area of the larynx is approximately 7% greater than the trachea

b. flexed head and neck position significantly increases ZI

c. greatest drops in airway pressure occur at the nostril

Question 31

Which of the following statements is correct

a. During exercise, the sympathetic tone increases, capacitance vessels are constricted, and the airway diameter is increased

b. During exercise, the sympathetic tone increases, capacitance vessels are dilated, and the airway diameter is increased

c. Injury to the sympathetic trunk innervating the nasal turbinate region (e.g., in Horner syndrome) can cause complete nasal occlusion of the opposite side

d. Injury to the parasympathetic trunk innervating this region (e.g., in Horner syndrome) can cause complete nasal occlusion of the affected side.

Answer 31

a. During exercise, the sympathetic tone increases, capacitance vessels are constricted, and the airway diameter is increased

Injury to the sympathetic trunk innervating this region (e.g., in Horner syndrome) can cause complete nasal occlusion of the affected side.

Question 32

Which of the following statements is correct

a. styloglossus attaches to the basihyoid and thyrohyoid bones and is innervated by the hypoglossal nerve

b. styloglossus attaches to the stylohyoid bone and the ceratohyoid bone and is innervated by the hypoglossal nerve

c. genioglossus attaches to the basihyoid and ceratohyoid bones and is innervated by the hypoglossal nerve

d. geniohyoideus attaches to the lingual process of the basihyoid bone and is innervated by the mandibular branch of the trigeminal nerve

Answer 32

c. genioglossus attaches to the basihyoid and ceratohyoid bones and is innervated by the hypoglossal nerve

all innervated by the hypoglossal nerve
hyoglossus - basihyoid and thyrohyoid bones

styloglossus - stylohyoid bone

genioglossus - basihyoid and ceratohyoid bones

geniohyoideus - lingual process of the basihyoid bone

Question 33

Which of the following statements is correct

a. The rostral hyoid muscles Hyoglossus, Styloglossus, Genioglossus, Geniohyoideus are innervated by the hyoglossal nerve

b. The rostral hyoid muscles Hyoglossus, Styloglossus, Genioglossus, Geniohyoideus are innervated by the hypoglossal nerve

c. The rostral hyoid muscles Hyoglossus, Styloglossus, Genioglossus, Geniothyroideus are innervated by the hyoglossal nerve

d. The rostral hyoid muscles Hyoglossus, Styloglossus, Genioglossus, Geniothyroideus are innervated by the hypoglossal nerve

Answer 33

b. The rostral hyoid muscles Hyoglossus, Styloglossus, Genioglossus, Geniohyoideus are innervated by the hypoglossal nerve

Question 34

Which of the following statements is correct

a. The hypoglossal nerve innervates the thyrohyoideus muscle, which draws the larynx rostrally and dorsally and the root of the tongue caudally by its attachments to the thyrohyoid and basihyoid bones

b. The hypoglossal nerve also innervates the thyrohyoideus muscle, which draws the larynx rostrally and ventrally and the root of the tongue caudally by its attachments to the thyrohyoid and basihyoid bones

c. The hypoglossal nerve also innervates the thyrohyoideus muscle, which draws the larynx rostrally and dorsally and the root of the tongue rostrally by its attachments to the thyrohyoid and basihyoid bones

d. The hypoglossal nerve also innervates the thyrohyoideus muscle, which draws the larynx rostrally and dorsally and the root of the tongue caudally by its attachments to the thyrohyoid and ceratohyoid bones

Answer 34

a. The hypoglossal nerve innervates the thyrohyoideus muscle, which draws the larynx rostrally and dorsally and the root of the tongue caudally by its attachments to the thyrohyoid and basihyoid bones

Question 35

Which of the following statements is correct

a. The tongue is attached to the hyoid bone via the genioglossus and hyoglossus muscles

b. The geniohyoid and genioglossus muscles pull caudally and ventrally

c. The sternohyoid and sternothyroid muscles pull in a caudal dorsal direction

d. None of the above

Answer 35

a. The tongue is attached to the hyoid bone via the genioglossus and hyoglossus muscles

Question 36

Which of the following statements is correct

a. Muscles controlling the position of the pharynx are the dorsal cricoarytenoid, genioglossus, geniohyoid, styloglossus, sternothyroid and thyrohyoid.

b. Muscles controlling the position of the hyoid apparatus are the dorsal cricoarytenoid, genioglossus, geniohyoid, styloglossus, sternothyroid and thyrohyoid.

c. Muscles controlling the position of the hyoid apparatus are the dorsal cricoarytenoid, genioglossus, geniohyoid, styloglossus, sternothyroid and stylohyoid.

d. Muscles controlling the position of the pharynx are the dorsal cricoarytenoid, genioglossus, geniohyoid, styloglossus, sternothyroid and stylohyoid.

Answer 36

b. Muscles controlling the position of the hyoid apparatus are the dorsal cricoarytenoid, genioglossus, geniohyoid, styloglossus, sternothyroid and thyrohyoid.

Question 37

Which of the following statements is correct

a. During DDSP expiratory tracheal pressure increases

b. During DDSP expiratory pharyngeal pressure increases

c. During DDSP expiratory tracheal pressure decreases

d. DDSP does not affect expiratory pressure

Answer 37

a. During DDSP expiratory tracheal pressure increases

During DDSP expiratory pharyngeal pressure decreases

Question 38

Contraction of the stylopharyngeus muscles raises the wall of the dorsal nasopharynx

Answer 38

Contraction of the stylopharyngeus muscles raises the wall of the dorsal nasopharynx