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Chapter 22
Respiratory System
I.
INTRODUCTION
A. Functions of the respiratory system
1. Supply the body cells with oxygen
2. Remove carbon dioxide
B. Events of Respiration
1. Pulmonary ventilation
2. External respiration
3. Transport of respiratory gases
4. Internal respiration
II.
FUNCTIONAL ANATOMY OF THE RESPIRATORY SYSTEM
A. Overview: two zones
1. Conduction zone (passageways or conduits for air)
2. Respiratory zone (locations of gas exchange)
B. Nose and Paranasal Sinuses
1. Functions
a. Provide airway
b. Moisten and warm entering air
c. Filter and cleanse air
d. Resonation for speech
e. Olfaction
2. Structure
a. External structures and functions
b. Internal structures and functions
c. Histology
i. Olfactory mucosa
ii. Respiratory mucosa
C. Pharynx (throat)
1. Location
2. Functions
3. Structure
a. Three regions
i. Nasopharynx
ii. Oropharynx
iii. Laryngopharynx
b. Tonsils and general locations
c. Histology
D. Larynx (voicebox)
1. Location
2. Function
3. Structure
a. Cartilages
i. Paired (arytenoids, cuneiform, corniculate)
ii. Unpaired (epiglottis, thyroid, cricoid)
b. Vocal ligaments
c. Vocal folds
d. Histology (hyaline versus elastic cartilage)
4. Voice production and speech
E. Trachea
1. Location
2. Function
3. Structure
4. Histology
F. Bronchial Tree
1. Conducting zone
a. Right and left primary bronchi
b. Secondary (lobar) bronchi
c. Tertiary (segmented) bronchi
d. Bronchioles
e. Terminal bronchioles
2. Respiratory Zone
a. Respiratory bronchioles
b. Alveolar ducts
c. Alveolar sacs
d. Alveoli
3. Respiratory membrane
a. Type I cells and function
b. Type II cells and function
c. Alveolar macrophages
G. Lungs and Pleural Coverings
1. Gross anatomy of the paired lungs
a. Lobes, lobules, and fissures
b. Surfaces (costal, mediastinal, diaphragmatic)
c. Cardiac notch and hilus
2. Blood supply
a. Pulmonary arteries and veins
b. Bronchial arteries and veins
c. Pulmonary capillary networks
3. Pleura
a. Parietal pleura
b. Visceral pleura
c. Pleural fluid
III.
MECHANISMS FOR BREATHING
A. Pressure relationships in the thoracic cavity
1. Atmospheric pressure
2. Intrapulmonary pressure
B.
C.
D.
E.
3. Intrapleural pressure
4. Transpulmonary pressure
Pulmonary ventilation
1. Boyle’s Law
2. Mechanism of inspiration
3. Mechanism of expiration
4. Factors influencing pulmonary ventilation
a. Airway resistance
b. Alveolar surface tension forces
c. Lung compliance
Respiratory Volumes and Capacities
1. Respiratory volumes
a. Tidal volume (TV)
b. Inspiratory reserve volume (IRV)
c. Expiratory reserve volume (ERV)
d. Residual volume
2. Respiratory capacities
a. Inspiratory capacity
b. Functional residual capacity
c. Vital capacity
d. Total lung capacity
Dead space
Non-respiratory air movements
IV.
MECHANISMS FOR GAS EXCHANGE
A. Basic gas properties
1. Dalton’s Law of Partial Pressure
2. Henry’s Law
B. Composition of alveolar gases
C. External gas exchange and the factors influencing it
1. Thickness of the respiratory membrane
2. Partial pressure of gases and gas solubilities
3. Amount of surface area available for gas exchange
D. Internal gas exchange
V.
TRANSPORT OF RESPIRATORY GASSES
A. Oxygen transport
1. Association of oxygen to hemoglobin
a. Oxyhemoglobin
b. Deoxyhemoglobin
2. Factors influencing oxygen affinity to hemoglobin (saturation)
a. Partial pressure of oxygen
b. Partial pressure of carbon dioxide
c. Temperature
d. pH
e. Hemoglobin-Nitric oxide partnership
3. Impairments of oxygen transport
a. Anemic hypoxia
b. Ischemic hypoxia
c. Histotoxic hypoxia
d. Hypoxemic hypoxia
e. Carbon monoxide poisoning
B. Carbon transport
1. Types
a. Bicarbonate ions
b. Dissolved in plasma
c. Carbaminohemoglobin
2. Haldane effect
3. Influence of carbon dioxide on blood pH
VI.
CONTROL OF RESPIRATION
A. Neural mechanisms
1. Medullary respiratory centers
a. DRG= Inspiratory center
b. VRG= Expiratory center
2. Pontine center
B. Factors influencing breathing rate and depth
1. Pulmonary irritant reflex
2. Inflation reflex
3. Higher brain centers (hypothalamus and cortical controls)
4. Chemical factors
C. Other factors causing respiratory adjustments
1. Exercise
2. High altitudes
VII.
HOMEOSTATIC IMBALANCES
A. Nasal cavity and sinuses
1. Rhinitis
2. Sinusitis
3. Epistaxis
B. Pharynx
1. Pharyngitis
2. Sleep apnea
C. Passageways (larynx, trachea, and bronchial tree)
1. Laryngitis
2. Tracheal obstruction (Heimlich Maneuver)
3. Chronic bronchitis
4. Asthma attack
D. Lungs and pleura
1. Pleurisy
2. Pneumonia
3. Pneumothorax
4.
5.
6.
E. Other
1.
2.
3.
4.
5.
6.
Atelectasis
Emphysema
Tuberculosis
Chronic Obstructive Pulmonary Disease (COPD)
Dyspnea
Infant Respiratory Distress Syndrome (IRDS)
Oxygen toxicity
Hypocapnia
Lung cancer