Respiratory System Flashcards
Functions of the respiratory system
Gaseous exchange
Acid-base balance
Phonation
Pulmonary defence mechanism
Pulmonary metabolism
Components of the respiratory system
-superior lobe
-middle lobe
-inferior lobe
What are the functional zones in the airways
Conducting zone
Respiratory zone
Outline the conducting zone
One place to another
First 16 generations
No alveolar exchange
Consists of trachea, bronchi, bronchioles
Outline the respiratory zone
Respiratory element of active gaseous exchange
Alveoli present between generation 17-23
Gaseous exchange
What are the muscles involved in respiration
Diaphragm
Intercostals
Accessory muscles
Are respiratory muscles skeletal or smooth muscles
Skeletal
Compare the diaphragm to intercostal muscles
Diaphragm is most powerful, intercostals are less powerful
How is respiratory air flow determined
By the pressure difference between mouth and alveoli
Define Pip
intrapleural pressure (intrathoratic pressure)
Define Ptp
transpulmonary pressure
Define Palv
Alveolar pressure
Define Patm
Atmospheric pressure
Name factors affecting breathing
Resistance
Compliance
Outline resistance
Resistance of respiratory tract to airflow during inspiration & expiration
Affected by diameter of airways
-expiratory problem
-increasing respiratory rate
Children are at greater risk as they have:
Smaller airways
Higher resting respiratory rates
Outline compliance
Measure of the lungs ability to stretch and expand (distensability of elastic tissue)
Expandability of lungs:
Low compliance-fibrosis
High compliance- emphysema
Value varies as lungs inflates
Examples of obstructive diseases
Asthma
Bronchitis
COPD
Outline Asthma: Type 1 hypersensitivity
Allergic or immediate hypersensitivity
Develop IgE antibodies in response to harmless antigens
Outline the initial allergen encounter in asthma
Allergen inhaled, ingested or by contact
Adaptive immune response by B cells that form plasma cells to make IgE to allergen, IgE enters circulation and binds to mast cells in tissues
Outline the subsequent allergen encounter
Allergen inhaled, injected or by contact
Cross-linkage causes mast cells to degranulate and release:
-vasoreactive amines (histamine)
-cytokines/chemokines
-leukotrienes
What is a restrictive disease.
Anything that decreases compliance
Outline Emphysema
Destruction of alveolar walls- large air spaces that are not cleared of air on exhalation (air trapping)
↓elastic fibres → ↓elastic recoil
Characteristic ‘barrel chest’
↓ gas exchange → ↓O2 diffusion → ↓O2 levels in blood
Consistent exposure to irritants- smoke,dust,chemical irritants
Outline surfactant
Lipoprotein secreted by Type II alveolar cells
Part of the liquid film lining the alveoli
Lowers surface tension
When surfactant lowers surface tension what does it cause
Increases compliance
Improves work of breathing
What are the two principle causes of COPD
(Chronic Obstructive Pulmonary Disease)
Emphysema and Chronic Bronchitis
