Respiratory Flashcards
What are the non-respiratory functions of the system?
- Traps and dissolves blood clots
- Defends against microbes
- Ventilation through airways contributes to heat loss and water loss
- important resorvoir for blood
- Phonation
- Metabolic functions
What is partial pressure?
It is the pressure exerted by a gas
How are the trachea and bronchi protected from collapsing?
They have rings of cartilage
What is dead space?
The volume of gas within the respiratory system where no gas exchange takes place. Anatmoical dead space is 150ml
Dead space occurs when there is no effective airflow and no blood flow
What is tidal volume?
Volume of air breathed in and out in one breath (Normally 500ml)
What is the respiratory frequency?
Number of breaths per min (12 breaths)
What is minute ventilation (VE)?
Tidal volume x respiratory frequency
500 x 12 = 6000 ml / min
What is dead space ventilation?
Volume of dead space x respiratory frequency
150ml x 12 = 1800 ml / min
What is alveolar ventilation (VA)
Minute vent - dead space vent
6000 - 1800 = 4200 ml / min
What is FRC?
The amount of air left in the lung at the end of expiration (approx 2.5 L at rest).
What is transmural pressure?
Pressure difference across a wall
What is pneumothroax?
When the balance is lost (lung pulled in and chest wall pushed out). This is by a hole in the chest wall so air goes into these spaces
What is Boyle’s Law?
The pressure exerted by a constant number of gas molecules in a container is inversely proportional to the volume of the container. Increasing the size of the container decreases pressure and decreasing the size of the container increases pressure.
What are the inspiratory muscles?
External intercostals and sternocleidomastoid and scalenes
What are the expiratory muscles?
External oblique, internal oblique and internal intercostals
What happens during inspiration?
- Thoracic cavity enlarges
- Due to pleural membranes, lungs move out with thorax
- Lungs expand (volume increases)
- Alveolar pressure less than pressure outside
- AIR MOVES IN
What happens during expiration?
- Chest wall moves inward
- Volume of thorax decreases
- Lungs recoil
- Alveolar pressure greater than pressure outside
- AIR MOVES OUT
Define Inspiratory Reserve Volume
The maximal amount of additional air that can be expired from the lungs by determined effort after normal expiration
Define Expiratory Reserve Volume
The additional amount that can be expired from the lungs by determined effort after normal expiration
Define Residual Volume
The volume of air still remaining in the lungs after the most forcible expiration possible