5. Define pharynx. List its 3 regions.

Pharynx (throat) - funnel-shaped skeletal muscle tube that connects the nasal cavity & mouth superiorly to the larynx & esophagus inferiorly

Regions
1 nasopharynx - superior
2 oropharynx - middle
3 laryngopharynx - inferior

6. Describe locations and functions of nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx - posterior to nasal cavity, inferior to sphenoid bone & superior to level of soft palate
Function - passageway for air (during swallowing the soft palate & uvula close off the nasopharynx & prevent food from entering nasal cavity)

Oropharynx - lies posterior to the oral cavity & is continuous with it through an archway called the isthmus of the fauces
Function - passageway for food and air

Laryngopharynx - lies directly posterior to the upright epiglottis and extends to the larynx, where the respiratory & digestive tracts diverge
Function - passageway for food and air

7. Describe location and functions of larynx.

Larynx (voice box) - cartilaginous organ located between the pharynx & trachea

functions
maintains patent (open) airway
switching mechanism to route air & food into proper channels
epiglottis - covers laryngeal opening during swallowing;stops air passage
voice production

8. Explain the function of the larynx and identify its structures from verbal descriptions.

Structure
opens into laryngopharynx superiorly & continuous with trachea posteriorly

attached to hyoid bone

9 cartilages connected by membranes & ligaments
all are hyaline cartilage except epiglottis which is elastic cartilage
thyroid cartilage - large, shield-shaped cartilage
arytenoid cartilages - one of 3 pairs of small cartilages forming part of the lateral & posterior walls of the larynx; anchor the vocal cords

9. Explain how the larynx and other structures in the head produce vocal sounds.

-true vocal cords vibrate to produce sound as air rushes up from lung
-Speech - involves the intermittent release of expired air and opening & closing glottis
-Intrinsic laryngeal muscles change length of vocal cords & size of glottis
-pitch - frequency of vibration of vocal cords; determined by vocal cords’ length & tension
-loudness - depends upon force at which the air passes across vocal cords; ↑ force = ↑ sound
-Pharynx - acts as a resonating chamber to amplify & enhance sound quality
-Sound is “shaped” into language
cooperation between pharynx, tongue, soft palate, & lips

10. Describe the structure and function of trachea. List its layers and describe composition of each.

Trachea (windpipe) - flexible cartilage-reinforced tube extending from the larynx to the bronchi

Functions
conducts air from larynx to bronchi
warms air, cleanses it of most impurities, & saturates it with water vapor

mucosa - innermost layer(goblet cells & ciliated epithelium)

submucosa - middle layer(connective tissue
contains seromucous glands that produce mucus
supported by 16 to 20 C-shaped rings of hyaline cartilage)

adventitia - outermost layer(connective tissue)

11. Explain the branching and naming of bronchi and bronchioles.

-air passageways branch about 23 times
-tips of bronchial tree - site where conducting zone structures give way to respiratory zone structures

12. Describe the structural changes that occur as conducting tubes become smaller.

-Bronchi - trachea divides to form the right & left main (primary) bronchi which enter the medial depression of each lung
-Main (primary) bronchi - subdivide into lobar (secondary) bronchi
there are 3 lobar bronchi on the right & 2 on the left;each supplies a lung lobe
-Lobar (secondary) bronchi - subdivide into segmental (tertiary) bronchi
-Bronchi continue to subdivide into smaller & smaller bronchi (fourth-order bronchi, fifth-order…)
-Bronchioles - < 1mm in diameter
-Terminal bronchioles -smallest bronchioles

13. Define respiratory bronchiole, alveolar duct, alveolar sac, and alveoli.

respiratory bronchioles - scattered alveoli; lead into alveolar ducts

alveolar ducts - lead into alveolar sacs

alveolar sacs - terminal clusters of alveoli

alveoli - individual air sacs (provides large surface area)

14. Order structures in the respiratory tract from trachea to alveoli.

trachea → main (primary) bronchi → lobar (secondary) bronchi → segmental (tertiary) bronchi → fourth order bronchi → fifth order bronchi → …

15. Describe the structure of the respiratory membrane.

Respiratory membrane - blood-air barrier composed of both alveolar and capillary walls along with their fused basement membranes

16. Explain functions of the different types of alveolar cells and the alveolar pores.

type I alveolar cells - alveolar walls are composed primarily of a single layer of squamous epithelium (tan in diagram)
type II alveolar cells - scattered among the type I cells; secrete surfactant (green in diagram)
alveolar macrophages - keep alveolar surfaces sterile (purple in diagram)

17. Identify the gross structures of the lungs from verbal descriptions.

-root - site of vascular & bronchial attachments to mediastinum
-hilum - indentation that contains blood vessels, bronchi, lymph vessels, & nerves
-costal surface - anterior, lateral, and posterior lung surfaces; in close contact with ribs
-apex - narrow superior tip
-base - inferior surface that rests on diaphragm
-cardiac notch - cavity in left lung that accommodates heart
-left lung - separated into superior and inferior lobes by oblique fissure; smaller lung
-right lung - separated into superior, middle, & inferior lobes by oblique and horizontal fissures
-bronchopulmonary segments - each lung contains 8-10, one for each tertiary (segmental) bronchus

18. Explain the general flow of blood and function of the bronchial circulation.

Blood supply to lungs
pulmonary circulation
bronchial circulation

Bronchial circulation
bronchial arteries - provide systemic blood to lung tissue
arise from aorta, enter lungs at hilum, and supply all lung tissue except alveoli; not involved in air exchange
bronchial veins - carry some blood but also anastomose with pulmonary veins which carry most of venous blood back to heart

19. Describe pleura, parietal pleura, visceral pleura, pleural cavity, and pleural fluid.

Pleura - thin, double-layered serosa

parietal pleura - covers thoracic wall & superior face of diaphragm; continues around heart & between lungs

visceral pleura - covers external lung surface

pleural cavity - slit-like cavity between the parietal & visceral pleurae; contains pleural fluid secreted by pleurae

Pleural fluid - lubricating fluid secreted by pleurae

20. List functions of the pleural fluid.

allows lungs to glide easily over the thorax wall
surface tension of pleural fluid resists separation of pleurae
causes lungs to cling tightly to thorax wall (adhesion)
lungs expand & recoil passively as thoracic cavity alternately increases & decreases during breathing

21. Define inspiration and expiration.

inspiration - period when air flows into the lungs

expiration - period when gases exit the lungs

22. Define atmospheric pressure, intrapulmonary pressure, intrapleural pressure, and transpulmonary pressure.

intrapulmonary pressure (Ppul) - pressure in the alveoli

intrapleural pressure (Pip) - pressure in the pleural cavity

Transpulmonary pressure - the difference between intrapulmonary pressure & intrapleural pressure

atmospheric pressure (Patm) - the pressure exerted by the air (gases) surrounding the body

23. Explain Boyle’s law and the relationship between gas pressure and volume.

-volume changes lead to pressure changes
-pressure changes lead to flow of gases to equalize pressure
-gases always fill their container

Boyle’s law - relationship between pressure & volume
P1V1 = P2V2

-at constant temperature, the pressure of a gas varies inversely with its volume
-↑ volume → ↓ pressure (gas molecules further apart)
-↓ volume → ↑ pressure (molecules closer)

24. Explain how intrapulmonary pressure varies with inspiration and expiration. Explain how it reaches equilibrium with atmospheric pressure.

-falls during inspiration ( increase Ppul); less than Patm

-rises during expiration (decrease Ppul); greater than Patm

-eventually Ppul reaches an equilibrium with Patm (Ppul = Patm)
-alveolar pores play a big part in pressure equalization process

25. Explain the importance of intrapleural pressure remaining negative. Explain how negative pressure is maintained.

Pip must be negative relative to Ppul to maintain pressure gradient; without it air will not move into the lungs

Pip should always be about 4 mm Hg less than Ppul

amount of pleural fluid in pleural cavity must be minimal to maintain negative Pip

lymphatics continuously drain pleural fluid out of pleural cavity

26. Contrast forces that pull lungs away from the thoracic wall with forces that keep the lungs from collapsing.

Forces that pull the lungs (visceral pleura) away from the thoracic wall (parietal pleura)
lung recoil - lung elasticity causes lungs to assume the smallest possible size
-surface tension of alveolar fluid - fluid molecules attract each other, drawing alveoli to smallest possible size

Opposing force that keeps lungs from collapsing
-elasticity of chest wall - pulls thorax outward & expands lungs
-Neither force totally wins but negative pressure is maintained

27. Explain what occurs when transpulmonary pressure is high, normal, or low.

normally, Ppul - Pip = 4 mm Hg

excess pleural fluid causes increase Pip with decrease transpulmonary pressure

amount of transpulmonary pressure determines lung size;increase transpulmonary pressure = increase lung size

any condition that equalizes Pip with Ppul or Patm causes immediate lung collapse
pneumothorax - presence of air in the pleural cavity

28. Define pneumothorax.

pneumothorax - presence of air in the pleural cavity

29. Explain the sequence of events in quiet inspiration.

30. Define forced inspiration and name some of the muscles involved.

Forced inspiration - accessory muscles aid inspiration during vigorous activity and in some chronic obstructive pulmonary diseases; increases thoracic volume

Muscles
several muscles including the scalenes, sternocleidomastoid, & pectoralis minor raise the ribs more than quiet inspiration
erector spinae muscles extend the back

31. explain the sequence of events in quiet expiration.

32. Define forced expiration and name some of the muscles involved.

Forced expiration - accessory muscles aid expiration
important when precise regulation of airflow from the lungs is desired (for example, singing)

muscles
primarily the internal oblique, external oblique, & transversus muscles of the abdominal wall

33. Summarize pressure and volume changes during inspiration and expiration: intrapulmonary pressure, intrapleural pressure, and volume of breath.

34. Define airway resistance, surface tension, surfactant, and lung compliance.

Airway resistance - the major nonelastic source of resistance to gas flow is friction encountered in the respiratory passageway

Surface tension - liquid molecules are more attracted to each other than to gas molecules at a gas-liquid boundary

Surfactant - decreases the cohesiveness of water molecules which reduces surface tension

Lung compliance - degree of “stretchiness”; a measure of the change in lung volume that occurs with a given change in the transpulmonary pressure

35. Define respiratory volumes and respiratory capacities.

Respiratory volumes - measures amount of air that can or cannot be exchanged during breathing

Respiratory capacities - sum of respiratory volumes
indicates an individual’s respiratory status

Both values are gender, age, and weight dependent

36. Define tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. Relate each to a spirographic tracing.

Tidal volume (TV) - amount of air inhaled or exhaled with each breath under resting conditions (500ml)

Inspiratory reserve volume (IRV) - amount of air that can be forcibly inhaled after a normal tidal volume inspiration (2100-3200ml)

Expiratory reserve volume (ERV) - amount of air that can be forcibly exhaled after a normal tidal volume expiration (1,000-1,2000ml)

37. Define inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity. Know equations for each.

Inspiratory capacity (IC) - maximum amount of air that can be inhaled after a normal tidal volume expiration
IC = TV + IRV

Functional residual capacity (FRC) - amount of air remaining in lungs after a normal tidal volume expiration
FRC = ERV + RV

Vital capacity (VC) - maximum amount of air that can be expired after a maximum inspiratory effort
VC = IRV + TV + ERV

Total lung capacity (TLC) - sum of all respiratory volumes; total air volume after maximal inspiration
TLC = IRV + TV + ERV + RV

38. Define pulmonary function tests and spirometry. Explain clinical uses for these tests.

Pulmonary Function Tests (PFT) - group of tests that evaluate how well lungs work
-measure how well lungs take in and release air & how well they move gases like O2 into the body’s circulation
-various lung volumes & capacities are often abnormal in people with pulmonary disorders

Spirometry - most common pulmonary function test
-breath into a mouthpiece connected to a small electronic measuring device called a spirometer
-measures how much air is inhaled &exhaled and how fast a patient can exhale
-evaluates losses in respiratory function & follows course of certain diseases

39. List types of respiratory controls. Describe the theoretical mechanism for respiratory rhythm.

Respiratory control involves higher brain centers, chemoreceptors, and other reflexes

Neural controls
-ventral respiratory group - in medulla; contains inspiratory neurons that fire to induce inspiration & inhibitory neurons that fire to stop inspiration (induces expiration); sets up respiratory rhythm
-other neural centers - influence & modify the activity of the medullary neurons
-respiratory rhythm - still cannot be fully explained

Chemical factors
-most important are changing levels of CO2, O2, and H+
-rising CO2 levels influence respiration more than other chemicals

40. Describe causes and features of respiratory disorders: restrictive lung diseases, COPD (emphysema, bronchitis), asthma, and lung cancer.

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