Respi Physio I Flashcards
Respiratory system is divided into:
- Upper Airways - Nose, Sinuses, Larynx
- Lower Airways - Trachea, Airways, Alveoli
Functions of the Nose (4)
- Nostrils condition air during inspiration and warm the air
- Humidifies the air via capillaries
- Filters air
- Sense of smell
Sinuses (4)
Frontal Sinuses
Maxillary Sinuses
Sphenoid Sinuses
Ethmoid Sinuses
Functions of the Sinuses (2)
- Lightens skull
- Resonance to voice
Structures of the Larynx (3)
- Vocal Cords
- Epiglottis
- Arytenoids
Functions of the Larynx (3)
- Vocal Cords: Protects airway, produces sounds
- Epiglottis: Covers vocal cords when swallowing
- Arytenoids: Covers vocal cords when swallowing
Structures of the Trachea
- Adventitia
- Hyaline Cartilage
- Trachealis muscle
- Submucosa with submucous glands
- Mucosa
Shape of Hyaline Cartilage in Trachea
C-shaped
Function of C-shaped Hyaline Cartilage in Trachea
Bolus causes dilation in esophagus when swallowing. Shape will prevent aspiration.
Parts of the Lower Airways
Trachea
Main stem bronchi
Lobar bronchi
Segmental bronchi
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sac
How many generations of airways?
23
Right vs Left bronchi
Right is wider, shorter and more vertical
Prone to aspiration
Airways are divided into 2:
Conducting airways
Respiratory unit
What happens in the conducting airway?
No gas exchange occurs
Parts of conducting airways
Trachea
Main stem bronchi
Lobar bronchi
Segmental bronchi
Terminal bronchioles
What is the respiratory unit?
Where gas exchange occurs
Parts of the respiratory unit:
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Respiratory Bronchiole is made of:
Respiratory epithelium that maintains periciliary fluid
Cough reflex
- 2.5L of air rapidly inspired
- Epiglottis closes
- Abdominal muscles contract
- Epiglottis opens
Sneeze reflex
- 2.5L of air rapidly inspired
- Epiglottis closes
- Abdomibal muscles contract
- Epiglottis opens
- Uvula depression
Weight of lungs
1kg (60% tissue, 40% blood)
Responsible for most of lung’s volume
Alveolar spaces
Gas exchange area
70-85m2
Right lung is made up of:
3 lobes with 2 fissures
Upper, Middle, Lower lobe
Oblique and Horizontal fissure
Left lung is made up of
2 lobes with 1 fissure
Upper, Lower lobe
Oblique fissure
Pleura of the Lungs is divided into:
Visceral Pleura
Parietal Pleura
Functions of pleural fluid
Keeps 2 pleura together
Has negative pressure
Anatomic Dead Space
Conducting Zone - no gas exchange
Normal value of anatomic dead space
150 mL
Alveolar Dead Space
Air in the respiratory unit that does not undergo gas exchange due to V/Q mismatch
Normal value of Alveolar Dead Space
0 mL
Physiologic Dead Space
Anatomic + Alveolar Dead Space
Functional Anatomic Unit of the Lung
Bronchopulmonary segments
How many bronchopulmonary segments?
8-10 per lung
Each with own blood and nerve supply
Type I Pneumocyte in Alveoli
96-98%
For gas exchange
Large, thin, flat
Type II Pneumocyte in Alveoli
2-4%
For surfactant production - decreases surface tension preventing alveolar collapse
Small, cuboidal
Rupture of alveolar walls occur due to:
Positive pressure in interstitial spaces greater than alveolar pressure (>0 mmHg)
Goblet Cells
Produces mucus for lubrication
In chronic smokers, goblet cells are
Hyperplastic and hypertrophic
Clara Cells or Club Cells
Produces GAGs
Metabolize air-borne toxins
Dust Cells are also called
Alveolar Macrophages
Function of Dust Cells
Removes trapped particles in alveoli
Lung Volumes (4)
ITER:
IRV
TV
ERV
RV
Lung Capacities (4)
Sum of 2 or more lung volumes
3, 2, 1
VC
IC
FRC
TLC
Normal volume of air in lungs
6L
How many mL in IRV?
3000 mL
How many mL in TV?
500 mL
Physiologic Dead Space (Anatomic + Alveolar) is computed using:
Bohr’s Equation:
VD = VT x (PaCO2 - PeCO2)/PaCO2
PaCO2 - PCO2 of arterial blood
PeCO2 - PCO2 of mixed expired air
Formula for Minute Ventilation
MV = VT x breaths/min
Formula for Alveolar Ventilation = Corrected Minute Ventilation
VA = (VT - VD) x breaths/min
Lung Volume and Capacity in females
20-25% lower
Inspiration causes:
Negative pressure
How many mL in ERV?
1200 mL
How many mL in RV?
1200 mL
Tidal Volume
Amount of air inhaled or exhaled during relaxed state
Tidal Volume is:
Amount inhaled or exhaled during relaxed state with each breath
Tidal Volume is divided into (500 mL):
Anatomic Dead Space (150 mL)
Respiratory Unit (350 mL)
Inspiratory Reserve Volume is
Amount of inspired air ABOVE tidal volume
**Used during exercise
Expiratory Reserve Volume is
Amount of air exhaled AFTER expiration of tidal volume
Reserve Volume is
Remaining air in the lungs AFTER MAXIMAL EXPIRATION
**Maintains oxygenation in the lungs between breaths
Inspiratory Capacity
Sum of IRV + TV
Functional Residual Capacity is
Sum of ERV + RV
Air in the lungs AFTER EXPIRING tidal volume
Amount of air remaining before and after tidal volume
Equilibrium or resting volume of the lung (no air in, no air out)
Functional Residual Capacity
Marker for lung function
FRC
FRC decreases = lung collapses
During FRC
Atmospheric pressure = alveolar pressure
Vital Capacity
Sum of IRV + TV + ERV
Maximum volume of air that can be inhaled or exhaled
Total Lung Capacity
Sum of IRV + TV + ERV + RV
Cannot be measured by spirometry
RV
FRC
TLC
Spirometry measures
Amount of exhaled air