Respiratory Flashcards
Which muscles are used for increased effort inspiration.
Diaphragm, external intercostal lifts and expand cage.
Accessory muscles.
Neck muscles.
Shoulder girdle muscles.
Which muscles are used for quiet breathing for inspiration
Diaphragm and external intercostals stabilize rib cage
Which muscles are used for increased effort on expiration
Internal intercostals and abdominal wall muscles
Which nerve innervates the diaphragm
Phrenic C3,4,5
What is Tidal Volume
The volume of air moved in and out the lungs during normal breathing.
Typical Value: at rest 6-7ml/kg
During exercise 15ml/kg
What is the Inspiratory Reserve Volume
The amount breathed in as deep as possible after expiration.
Typical value 3,000ml
What is Expiratory Reserve Volume
After inspiration, breathe out as much as possible.
Typical value: 1,500 ml
What is the residual volume and why does it exist
It is the air that remains in the lungs after maximal expiration.
Typical value: 1000ml
The rigid nature if the thorax and pleural attachments prevent complete expiration.
It CANT be measured by spirometry.
What are the 4 lung volumes and what do they equal?
Tidal volume, IRV, ERV and Residual Volume
All 4 = Total Lung Capacity
How is vital capacity calculated?
Tidal Volume + IRV + ERV
What is the functional residual capacity
Residual Volume + ERV
What is the Vital Capacity
The volume after a maximal expiration is made after a maximal inspiration.
Typical Value: 5,000 ml
How do restrictive lung diseases affect lung volumes?
Reduces: Residual Volume, Functional Residual Capacity, Vital Capacity and Total Lung Capacity.
Give 3 examples of Obstructive Lung Diseases
Asthma, COPD, Emphesyma
What happens to the residual volume in Obstructive Lung Diseases
The residual volume is decreased.
How is the volume of exhaled air effected by a restrictive lung disease
Remains at similar rate but the total volume exhaled significantly decreased.
How is the volume of exhaled air changed by an obstructive lung disease
Slower rate but fairly close to the total volume exhaled.
How is FEV1/FVC ratio used to distinguish between obstructive and restrictive lung diseases
A ratio below 0.7 is considered OBSTRUCTIVE
A ratio above 0.7 is considered RESTRICTIVE
What is the most important factor in airway flow?
The diameter of the airway as it is power of 4 in calculation
What is compliance?
Compliance is the change in lung volume per unit change in intrathoracic pressure
But compliance is not equal throughout the lung.
What is the aleveolar surfactant made up of and what is it produced by?
90% Phospholipid
10% Protein
Produced by Type II alveolar cells.
What does the surfactant do?
The surfactant acts as a detergent to reduce alveolar surface tension.
- increases pulmonary compliance
- prevents atelectasis - collapse of the lung
- aids alveolar recruitment
- minimises alveolar fluid
As alveolar volume increases, surfactant becomes…
More dispersed. Which equalises pressure between alveoli of different sizes.
What is partial pressure of a gas
Partial pressure of a gas in a mixture of gases is the pressure it would exert if it was the only gas
