Com Sci Exam 3

Boyle’s Law: Pressure and volume are inversely related. As lung volume increases, pressure decreases, and vice versa.

Rib cage: Protects thoracic organs, expands/contracts during breathing.

Trachea: Connects larynx to lungs; airway conduit.

Bronchial Tree: Branches into bronchi and bronchioles, ending in alveoli.

Lungs: Elastic organs responsible for gas exchange.

Pleurae: Visceral (lung surface) and parietal (chest wall) pleura.

Intrapleural Space: Thin fluid-filled space; maintains negative pressure.

Physiology: Prevents lung collapse, allows lungs to expand with thoracic wall.

Pneumothorax: Air enters intrapleural space, causing lung collapse.

Muscles of Breathing: Alter size/pressure of thoracic cavity.

Inhalation: Diaphragm contracts, rib cage expands.

Exhalation: Muscles relax or contract (forced) to reduce lung volume.

Diaphragm: Dome-shaped muscle; main driver of tidal inhalation.

Pressure Differences:

Inhalation: Atmospheric pressure > alveolar pressure.

Exhalation: Alveolar pressure > atmospheric pressure.

Tidal (Passive): Uses diaphragm.

Forced: Engages accessory muscles (e.g., intercostals, neck, chest).

Tidal: Passive elastic recoil.

Forced: Uses accessory muscles (abdominal, internal intercostals).

Tidal Breathing Cycle: Inhalation (active) ~40%; exhalation (passive) ~60%.

Lung Volumes vs. Capacities:

Volumes: Tidal, inspiratory reserve, expiratory reserve, residual.

Capacities: Vital, total lung, inspiratory, functional residual.

Spirometry: Graphs volumes/capacities; vital capacity = IRV + TV + ERV.

Developmental Changes: VC increases with age and body growth.

Life vs. Speech Breathing:

Life: Nose, 40/60 inhale/exhale, passive.

Speech: Mouth, 10/90 inhale/exhale, active.

Recoil Forces: Passive return of lungs/rib cage to rest post-inhalation.

Resting Expiratory Level: Balance point of lung recoil and thoracic expansion.

Lung Disease Types:

Obstructive: Narrowed airways (e.g., asthma, COPD).

Restrictive: Reduced lung expansion (e.g., fibrosis).

Symptoms:

Dyspnea: Shortness of breath.

Stridor: High-pitched, wheezing sound on inspiration.

Phonation

Source-Filter Independence: Source (vocal folds) operates separately from filter (vocal tract).

Phonation: Process of vocal fold vibration producing sound.

Laryngeal Anatomy:

Cartilages:

Unpaired: Thyroid, cricoid, epiglottis.

Paired: Arytenoids, corniculates, cuneiforms.

Bone: Hyoid (not part of larynx but supports it).

Abduction: Vocal folds apart (breathing).

Adduction: Vocal folds together (phonation).

Regions:

Glottal: Space between vocal folds.

Supraglottal: Above folds (resonance).

Subglottal: Below folds (pressure buildup).

Extrinsic Muscles: Elevate or depress larynx.

Intrinsic Muscles:

Adduction: Lateral cricoarytenoid, interarytenoids.

Abduction: Posterior cricoarytenoid.

Tension: Cricothyroid (lengthens), thyroarytenoid (shortens).

Histology of Vocal Folds:

Epithelium: Outer layer.

Lamina Propria: Superficial (gel-like), intermediate (elastic), deep (collagen).

Thyroarytenoid: Muscle forming body of fold.

Theories of Phonation

Myoelastic Aerodynamic Theory: Vocal fold vibration is due to muscle elasticity and aerodynamic forces.

Bernoulli Effect: Increased airflow = decreased pressure; helps folds close.

Pressure Relationships:

Subglottal pressure must exceed supraglottal for vibration.

Vibration Cycle:

Folds close → pressure builds → folds open → air escapes → folds pulled back.

Phasing:

Vertical: Inferior to superior fold closure.

Anterior-Posterior: Middle to edges.

Acoustic Features of Phonation

Quasi-periodic Wave: Regular but not perfectly periodic.

Complex Wave: Multiple frequencies.

Glottal Spectrum: Shows harmonics; falls in amplitude at higher frequencies.

Fundamental Frequency (F0): Controlled by vocal fold length, mass, tension.

Intensity: Controlled by subglottal pressure and medial compression.

Cover-Body Model

Cover: Epithelium + superficial lamina propria.

Body: Thyroarytenoid muscle.

Importance: Explains vibratory properties of vocal folds.

Articulation and Resonance

Valves: Lips, tongue, velum, vocal folds.

Consonants vs. Vowels:

Consonants: Obstructed airflow.

Vowels: Open vocal tract.

Consonant Classification: Place (e.g., bilabial), manner (e.g., stop), voicing.

Vowel Classification: Tongue height and advancement.

Source-Filter Theory:

Source (glottal), Filter (vocal tract).

Laryngeal Source: Periodic sound with harmonic structure.

Supraglottal Resonance:

Transfer function = effect of vocal tract on source.

Acts as filter; length/shape change = formant shifts.

Vocal tract = closed tube; odd-number multiple resonance.

Formants: F1 (height), F2 (advancement), lip rounding lowers F2.

Vowel Production and Perception

Differences:

Vowels: Periodic, open tract.

Consonants: Various sources (periodic/aperiodic).

Vowel Acoustics: