Essay questions

Question 1

Describe the role of the abdominal muscles in the inspiratory and expiratory phases of respiration

Answer 1

Inhalation depends upon the active muscle forces of the external intercostals and the diaphragm. In order to inhale, the thoracic cavity and lungs must expand. The 11 pairs of external intercoastal muscles run between the ribs on either side. Their contraction pulls the rib cage in an upward and outward direction, expanding the thoracic cavity. The diaghram attaches to the bottom six ribs on either side of the rib cage. At rest the muscle is shaped like an inverted bowl. Upon contraction, the muscle flattens out, thus increasing the vertical dimension of the thoracic cavity. Contraction of the diaghram and external intercoastals increases the volume of the thoracic cavity and lungs. Because air pressire and air volume have an inverse relationship, the increased volume results in a drop of pressure within the lungs (alveolar pressure).

Question 2

Describe the role of the abdominal muscles in the expiratory phases of respiration

Answer 2

For exhalation, the external intercoastal muscles and the diaphragm recoil back to their resting postions, causing the volume of the thoracic cavity to decrease. Alveolar pressure therefore increases and becomes higher than the atmospheric pressure. Thus air from the lungs is forced to exit the system through the nose or mouth. Additional mucsles may be recruited for inspiration and expiration when particularily large volumes of air are required. These include muscles of the rib cage and abdominal wall.

Question 3

Accessory muscles of Respiration (abdominal muscles) for expiration:

Answer 3

rectus abdominis, external oblique, internal oblique, transverse abdominis

Question 4

Contraction of the diaphragm and external intercostals increases the…

Answer 4

VOLUME of the thoracic cavity and lung

Question 5

Increase in volume of the thoracic cavity and lungs results in a…

Answer 5

drop of pressure within the lungs (alveolar pressure).

Question 6

When external intercostals and diaphragm muscles return to their resting position, volume of the thoracic cavity…

Answer 6

DECREASES

Question 7

Decrease in volume of the thoracic cavity causes…

Answer 7

alveolar pressure to INCREASE

Question 8

Identify 5 ways in which breathing for life changes when breathing for speech

Answer 8

• location of air intake
• ratio of time for inhalation versus exhalation
• volume of air inspired
• muscle activity for exhalation
• abdominal displacement

Question 9

Location of air intake

Answer 9

• when a person is breathing for like, air is inhaled and exhaled via the nasal passageway, which effectively warms, moistens and filters the air.
• breathing for speech occurs via the oral passageway, allowing for a quicker inhalation and production of oral sounds on the exhalation.

Question 10

ratio time for inhalation vs exhalation

Answer 10

• life breathing (40% inhalation, 60% exhalation)
• speech (10% inhalation, 90% exhalation).
• this allows for a sufficient number of per exhalation with quick replenishment of air that facilitates the uninterrupted flow of connected speech.

Question 11

volume of air inspired during quiet breathing

Answer 11

-during quiet breathing, approximately 500ml is inspired, depending on the age and gender of the individual (10% vital capaticty), which is approximately 5,000 ml.

Question 12

volume of air inspired during life breathing

Answer 12

• Inhalation for life breathing begins at REL-resting expiratory level- (35-40% of VC and goes up to a lung volume that is 50% of VC)
• The individual then exhales back down to REL.

Question 13

volume of air inspired during speech

Answer 13

• the volume inhaled for speech is variable, depending on the length and loudness of the upcoming utterance.
• volumes for normal conversation typically occur in the mid range of VC (35-60%) and are around twice as much as those involved in life breathing.
• At 60% of VC the corresponding alveolar pressure is approximately 10 cm H2O which is sufficient for most normal conversational utterances.
• This mid-volume range of VC is highly efficient because it requires very little respiratory muscle activity.

Question 14

volume of air inspired for longer louder utterances

Answer 14

For longer and louder utterances, speakers inhale to higher lung volumes and continue the exhalation into lower volumes.

Question 15

muscle activity for exhalation

Answer 15

• Exhalation for life breathing occurs passively, as the respiratory tissues recoil back to their rest positions due to gravity, muscle relaxation, and elasticity of the lung tissue.
• For speech purposes the rate of recoil must be controlled in order to prolong the exhalation.

Question 16

muscle activity for exhalation pressure above REL

Answer 16

For pressure above REL, the muscles of inspiration continue to contact in order to provide a counteracting checking force that prevents the thoracic cavity and lungs from deflating too quickly.

Question 17

muscle activity for exhalation to access expiratory reserve volume

Answer 17

To access the expiratory reserve volume and continue speaking below REL, the abdominal muscles are recruited. Contraction of the abdominal muscles forces the abdominal wall to press inward on the abdominal contents (stomach intestines etc). This, in turn, pushes the contents headward against the diaphragm, further decreasing the volume of the thorax and lungs so aire continues to be exhaled. The internal intercoastals may also contract to depress the rib cage. Speaking at lung volumes below REL thus requires considerable muscular effort in order to continue decreasing the lung volume for exhalation and to prevent the rib cage from recoiling outward in an inspiratory direction.

Question 18

abdominal displacement

Answer 18

The shape of the chest wall differs- Chest wall includes rib cage, diaphagm, abdominal wall and abdominal contents.

-For speech breathing, it has been reported that the abdomen is displaced further inward relative to the rib cage. This positioning lifts the rib diaphram (bc of the upward pressure on the abdominal on the abdominal contents) and expands the lower rib cage. The muscle fibers of the diaphragm are thereby placed in an optimal position for generating quick strong contractions. In addition, keeping the abdomen inward relative to the rib cage provides a platform against which the rib cage can more to control the varying lung volumes and air pressures necessary in connected speech. Movement of the rib cage is more efficient in changing lung volumes than movement of the abdomen because of the greater surface area of the lung that is adjacent to the rib cage. Therefore, the rib cage wall needs to more only one quarter of the distance that the abdominal wall does to achieve the same change in alveolar pressure.

Question 19

Define Resting Expiratory Level and explain how the measurement of percentage of vital capacity is derived and can be useful for characterizing aspects of speech production

Answer 19

REL refers to a state of equilibrium in the respiratory system in which alveolar pressure and atmospheric pressure are equalized and air is neither entering or exiting the system. This occurs at the very end of every inspiration and expiration. The endpoint of a quiet expiration is also called the end-expiratory level (EEL). Lung volumes and capacities provide a way of categorizing volumes of air inhaled and exhaled through the respiratory system. Volumes and lung capacities are measured with a spirometer in units of milliliters ml or liters l. Volumes and capacities are often described in terms of the percentage of vital capacity (VC) expended. VC is the maximum amount of air one is able to voluntarily breathe in and out. REL occurs at around 35-40% of VC. At that point, we can inhale 60-65% more air to fill the lungs to their maximum capactiy and can continue to exhale below REL to 0% VC.

Question 20

cricoarytenoid joints

Answer 20

The cricoarytenoid joints form the connection between the base of each arytenoid cartilage and the superior surface of the quadrate lamina of the cricoid. This laryngeal joint permitting rocking and gliding motion of the arytenoid cartilages. It also allows for a medial/lateral gliding motion of the arytenoid cartilages. These movements cause simultaneous bidirectional motion of the arytenoids. It regulates vocal fold adduction and abduction. Therefore when the muscles contract the arytenoid cartilages move in a rotational pattern. Depending on the muscle contracted the vocal process either moves medially and in a downward closing motion or laterally and in an upward opening motion. (figure 1.11 in textbook)

Question 21

cricothyroid joints

Answer 21

The cricothyroid joints are located where the inferior horns of the thyroid cartilage connect to the articular facet at each side of the cricoid cartilage.A laryngeal joint permitting movement of the cricoid and thyroid cartilages. These joints allow the thyroid cartilage to tilt superiorly and inferiorly and the cricoid cartilage to glide anteriorly and posteriorly. The effect of this movement is to increase the distance between the anterior commissure of the thyroid cartilage and the arytenoid cartilages. Increasing this distance tenses and stretches the vocal folds, increases frequency of vibration, creating a higher pitch. Decreasing this distance shortens the vocal folds, decreases frequency of vibration and lowers the pitch. (Figure 1.12 in textbook)

Question 22

Lateral Cricoarytenoid

Answer 22

• Originates at the lateral portion of the cricoid cartilages and inserts at the muscular process of each arytenoid cartilages.
• Contraction of this muscle moves the vocal processes towards each other which closes the membranous glottis.
• Adduction of the vocal folds.

Question 23

Interarytenoids

Answer 23

• These fibers run between the arytenoids.
• The transfers run horizontally and the obliques run on an angle.
• This muscle pulls the arytenoid cartilages towards each other to close the cartilaginous portion of the vocal folds.
• Adduction of the vocal folds.

Question 24

PCA

Answer 24

• This muscle is the only vocal fold ABDUCTOR.
• Originates at the posterior cricoid cartilage to the muscular process of each arytenoid.
• It pulls the muscular processes together and opens the vocal process. Therefore, the vocal folds and glottis opens.
• Damage to this muscle is problematic because there is only one muscle for abduction.

Question 25

Cricothyroid

Answer 25

2 parts of this muscle-

• pars recta runs from the cricoid cartilage and inserts into the inferior border of the thyroid cartilage
• pars oblique inserts into the inferior horn of the thyroid cartilage.
• when it contracts it pulls the thyroid cartilage down which lengthens and tenses the vocal folds creating a higher pitch.
• downward motion of the thyroid cartilage increases the distance between the vocal processes and the thyroid. -when the muscle relaxes pitch goes down.
• major regulator of frequency/pitch.

Question 26

thyroarytenoid

Answer 26

• forms the body of the vocal folds and is encased by the lamina propria.
• runs from the thyroid to the arytenoids.
• plays a more passive role and is acted on by other muscles.
• can contract and create internal (isometric) tension. -when the muscle gets more tense this increases vibration and therefore increases frequency/pitch.

Question 27

aryepiglottic

Answer 27

The fibers of the oblique interarytenoids extend up and intertwine into the aryepiglottic muscle. When contracted this muscle pulls the epiglottis down over the larynx.

Question 28

Aryepiglottic folds

Answer 28

Is the most superior valve of the larynx. They run from each side of the epiglottis to the arytenoids, and when they contract they pull the epiglottis over the airway entrance.

Question 29

False (Ventricular) Folds

Answer 29

Is the middle valve of the larynx. They are open during phonation and close naturally during swallowing (reflexive).

Question 30

True Vocal Folds

Answer 30

Is the most inferior and complex valve of the larynx. It is composed of 5 layers (epithelium, superficial layer, intermediate layer, deep layer, and the thyroarytenoid muscle).

Question 31

similarities of aryepiglottic, false, and true folds

Answer 31

All valves are made of connective tissues and muscle fibers. They all close reflexively during swallowing

Question 32

Describe the myoelastic aerodynamic theory. Include in your discussion an explanation of the mucosal wave, focusing on the biomechanics of vocal fold vibration, and the role of aerodynamic factors.

Answer 32

The myoelastic-aerodynamic theory is the accepted theory of how the vocal folds vibrate. The interarytenoids and lateral cricoarytenoids exert medial compression, pushing the vocal folds to midline. This causes pressure below the vocal folds (subglottal pressure) to build up and overcome the resistance, causing them to burst apart (positive pressure). When the vocal folds are open, a puff of air is released into the vocal tract, setting the air into vibration and becoming sound! One cycle of vocal fold vibration is an interaction of muscle forces, elastic recoil forces, and aerodynamic forces.

Question 33

Describe the vagus nerve in terms of structure, location, and function in vocalization and resonance

Answer 33

The Vagus nerve has its motor nuclei in the nucleus ambiguus in the brainstem. It is a very extensive nerve with branches to the soft palate, larynx, and visceral structures. The three branches of CN X that are important for voice are the Pharyngeal, Superior Laryngeal (SLN), and the Recurrent laryngeal (RLN).

Superior Laryngeal Nerve: It has two branches - the internal (sensory) and the external (motor, innervates cricothyroid muscle).

Recurrent Laryngeal Nerve: Innervates other intrinsic muscles - LCA, IA, PCA, TA.  This nerve is asymmetrical on the right and left sides.  The left size is more susceptible to damage because it is longer - this side loops around the aorta of the hearth.  The right side loops around the subclavian artery of the heart.