Chapter 6

Question 1

Respiratory Pathway (nares -> alveoli)

Answer 1

Nares -> Nasal Cavity -> Pharynx -> Larynx -> Trachea -> Bronchi -> Bronchioles -> Alveoli

Question 2

Inhalation

Answer 2

Muscles:
1. Diaphragm (contracts/flattens)
2. External intercostal muscles (contract)

Labored breathing neck and back muscles may also become involved

Intrapleural pressure lower than atomospheric pressure because expansion of chest cavity causes expansion of intrapleural space, decreasing its pressure

Question 3

Exhalation

Answer 3

Passive:
Muscles recoil:
1. Diaphragm (relax)
2. External intercostal muscles (relax)

Active:
1. Diaphragm
2. External intercostal muscles
3. Internal intercostal muscles (contract)
4. Abdominal muscles (contract)

Question 4

Surfactant

Answer 4

Reduces surface tension at air-liquid interface in alveoli
Prevents alveloi collapse

Question 5

Vital Capacity (VC)

Answer 5

Sum of inspiratory reserve volume, expiratory reserve volume, and tidal volume
VC = IRV + ERV + TV

Question 6

Respiratory Homeostasis

Answer 6

If CO2 levels too low, brain decreases respiratory rate to raise CO2 levels

Question 7

Immune Mechanisms in Respiratory System

Answer 7

• Vibrissae in nares
• Lysozyme in mucous membranes (Enzyme in nasal cavity, saliva, and tears that degrades peptidoglycan preventing infection)
• Mucociliary escalator
• Macrophages in lungs
• Mucosal IgA antibodies
• Mast cells

Question 8

Bicarbonate Buffer System

Answer 8

Question 9

Respiratory Failure

Answer 9

• Ventilation slows
• Less CO2 blown off
• Buffer equations shifts to right and more H+ generated
• Results in lower pH of blood

Question 10

Lung Gas Exchange

Answer 10

Relies on passive diffusion of oxygen and carbon dioxide

Facilitated by:
* Thin alveolar walls
* Multiple subdivisions of respiratory tree
* Differences in partial pressure of O2 and CO2

Question 10

Lung Gas Exchange

Answer 10

Relies on passive diffusion of oxygen and carbon dioxide

Facilitated by:
* Thin alveolar walls
* Multiple subdivisions of respiratory tree
* Differences in partial pressure of O2 and CO2

Question 11

Total Lung Capacity

Answer 11

Vital capacity (maximum volume of air that can be forcibly inhaled/exhaled) + residual volume (air that always remains in lungs to prevent alveoli from collapsing)

Question 12

Intrapleural Space

Answer 12

Bounded by parietal and visceral pleurae
* Contains small amount of fluid
* Introducing more fluid/air into intrapleural space can fill space causing collapse

Question 13

Epiglottis

Answer 13

Covers glottis during swallowing

Question 14

Ciliated Epithelial Cells

Answer 14

Line the trachea and bronchi

Question 15

Nares

Answer 15

Lined with vibrissae that help filter out particulate matter from inhaled air

Question 16

Pharynx

Answer 16

Behind nasal and oral cavity
Common pathway for food entering digestive system and air entering respiratory system

Question 17

Larynx

Answer 17

Contains vocal chords

Question 18

Spirometry

Answer 18

Measures lung capacities and volumes
* Can’t be used to determine total lung capacity because can’t determine residual volume

total lung capacity = vital capacity + residual volume