Ventilation and gas exchange Flashcards
What is minute ventilation?
The volume of air expired in one minute
What is respiratory rate?
The frequency of breathing per minute.
What is alveolar ventilation?
The volume of air reaching the respiratory zone per minute
what is anatomical dead space?
The capacity of the airways incapable of undertaking gas exchange
What is alveolar dead space?
The capacity of the airways that should be able to undertake gas exchange but cannot (Hypoperfused alveoli).
What is physiological dead space?
Equivalent to the sum of alveolar and anatomical dead space
What is hypoventilation?
Deficient ventilation the lungs, unable to meet metabolic demands (Increased PCO2) - acidosis
What is hyperventilation?
Excessive ventilation of lungs atop of metabolic demand (reduced PCO2) - alkalosis
What is hyperpnoea?
Increased depth of breathing to meet metabolic demand
What is hypopnea?
Decreased depth of breathing (inadequate to meet metabolic demand)
What is apnoea?
Cessation of breathing
What is dyspnoea?
Difficulty in breathing
What is bradypnoea?
Abnormally small breathing rate
What is tachypnoea?
Abnormally fast breathing rate
What is orthopnea?
Position difficulty in breathing (when lying down)
What does respiratory volume mean?
Term used to describe the volume of air moved by or associated with the lungs at a given point within the respiratory cycle
What does tidal volume mean?
Volume of air that occupies the lungs during periods of quiet breathing (500ml)
What does expiratory reserve volume mean (ERV)?
Volume of air that can forcefully be exhaled succeeding normal tidal expiration
What is inspiratory reserve volume?
Produced from deep inhalation, past tidal inspiration. This is the additional volume that is drawn into the lungs through forced inspiration.
What is residual volume?
The volume of air present in lungs upon maximum exhalation. The residual asset with breathing ability by preventing alveoli collapse
What is respiratory capacity?
Combination of 2+ selected volumes
What is total lung capacity?
Sum of all lung volumes (TV, ERV, IRV, and RV), represents the total amount of air that can occupy the lungs upon a forceful inhalation
What is the inspiratory capacity (IV)?
Tidal volume + inspiratory reserve volume
Maximum amount of air that can be inhaled past a normal tidal expiration
What is functional residual capacity?
Amount of air that remains in the lung after normal tidal expiration
FRC = Residual volume + expiratory reserve volume
What is vital capacity?
The amount of air that can be moved into or out of the lungs.
Sum of TV, ERV & IRV
What is the calculation to calculate minute ventilation?
tidal volume x breathing frequency
What is the calculator for alveolar ventilation?
[Tidal volume - dead space] x breathing frequency
What forms the anatomical dead space within the trachea and bronchioles?
The C-shaped cartilaginous rings within the conducting zone do not participate in gas exchange
What is dead space?
The respiratory system also contains anatomical dead space Air is present in the air away however does not reach the alveoli or participate in gas exchange.
How many generations are present within the superficial conducting zone?
16 generations; no gas exchange
150ml at FRC
How many generations form the respiratory zone?
7 generations
What volume of air reaches the respiratory zone?
350ml
What forms the alveolar dead space?
Non-perfused parenchyma - avascular alveoli therefore unable to conduct gas exchange considering that oxygen cannot be transferred to pulmonary circulation
How can dead space be increased? [example]
Anaesthetic circuit snorkelling
How can dead space be decreased? [Example]
Removal of conducting zone structures including: Tracheostomy, cricothyrotomy - interject further down for upper pharynx blockage
What surrounds the lung?
Pleural cavity
What type of membrane forms the pleura?
Serous membrane
What separates the two lungs from each other?
Mediastinum
What two layers form the pleura?
Visceral and parietal pleura
What is the outer layer of pleura?
Parietal pleura
What is the function of parietal pleura terms of connections?
Outer layer connects to the thoracic wall, the mediastinum and the diaphragm
Where do the visceral and parietal pleura connect?
They connect at the hilum
What is the space between the visceral and parietal layers?
Pleural cavity
What membrane surrounds the lungs?
pleural membrane
What is within the pleural cavity?
A foxed volume, and contains protein rich pleural fluid
The chest wall has a tendency to spring___?
Outwards
The lungs has a tendency to recoil____?
Inwards