Week 3: Introduction to the Respiratory System Flashcards
What is the conducting zone and whats it made up by?
- Is the region where no gas exchange occurs - It is made up of the trachea, bronchi and bronchioles (they are highway systems for air)
Whats the respiratory zone and whats it made up by?
- Is the actual site of gas exchange within the body - It includes the respiratory bronchioles, alveolar ducts and alveoli (bulk of gas exchange occurs in the alveoli)
What are the 2 main zones in the respiratory system?
Conducting and respiratory zone
What is the function of the conducting zone?
- Conducts air (it moves it) 2. Warms the air 3. Humidifies air 4. Cleans the air (it does this through the nasal hairs and nasal turbinates as we breath it in)
What is the first line of defence from preventing foreign particles from getting into the lungs?
Nasal hairs which work along side mucous.
What are the conchae and their function?
extensions within the nasal passage which increase the surface area of the nasal passage. This serves to increase the amount of nasal hairs and mucous that can clean, whilst also increasing the surface area of the capillaries (which allow water and heat exchange).
Particles only less than ___ can enter the lungs due to the first line of defence.
6 micrometers
What happens to particles 1-5 and under 1 micrometers when they make it passed the first line of defence in the upper respiratory system?
Trapped by bronchi by the mucous that lines it and particles smaller than 1 micrometer will end up in alveoli but will be engulfed by alveoli macrophages.
What are the 3 mechanisms which maintain airway patency?
- structural - c shaped cartilage rings which line trachea. 2. radial traction - relies on elastin and type 4 collagen (fibres pull the airway open like springs) 3. Pressure gradients - pressure inside greater than pressure outside
Structural mechanisms maintain patency of the __ and ___ whilst radial tension and pressure gradients maintain patency of the ___ and below
Structural mechanisms maintain patency of the trachea and bronchi, whilst radial tension and pressure gradients maintain the patency of the bronchioles and below
Explain boyles law in terms of how we breath
In order to breath in, we increase the volume of the chest volume, decreasing the chest pressure and thus drawing air into the lungs
What is an important feature of the pleura which helps the lungs to increase its volume when taking a breath?
there is a slight negative pressure that sucks the lungs out and holds the intercostal space.
What would happen when taking a breath if there is air accumulating in the pleural space?
The chest would move when taking a breath but the lungs wouldn’t.
What is intrapulmonary pressure
Pressure inside the lung
Explain the mechanism of inhalation
- Diaphragm contracts and thus moves inferiorly - External intercostals contract and thus moves ribs out and up - Both of these actions increase the volume of the lung, thus creating negative intrapulmonary pressure - Air flows in - Lungs increase in volume
Explain the mechanism of expiration
- There is elastic recoil - Lungs decrease in volume - There is positive intrapulmonary pressure - Air therefore flows out - (Note: expiration is passive at rest)
What is eupnea?
passive expiration from elastic recoil
what is hyperpnoea?
Increase in breathing
What is the difference between hyperpnoea and hyperventilation?
Hyperventilation is an increase in ventilation above that predicted by the metabolic rate (it is over breathing) if you go for a run and your breathing increases, its hyperpnoea, not hyperventilation (breathing has increased to match an increased metabolic rate or demand)
What is Vt?
Tidal volume
What is f
respiratory rate
what is V’E
amount of air moved each minute
What is VD
dead space which is the amount of air in the conducting zone
What is V’A
amount of air reaching the alveoli each minute
what is the formula for V’A
V’A=(VT-VD )* f
What is ERV
Expiratory Reserve volume (ERV) is the amount of additional air that you can force out of your lungs after you have expired normally (roughly 1000mL)
What is IRV
Inspiratory Reserve Volume (IRV) is the amount of additional air that you can inhale after you have inhaled normally (roughly 1900 – 3300mL)
What is RV
Residual Volume (RV) is the amount of air left in the lungs after a maximum expiration (roughly 1100mL)
What is IC
Inspiratory capacities (IC) is the amount of air you can take into the lungs after normal expiration is completed
What is FRC
Functional Residual Capacity (FRC) is the amount of air remaining in the lungs after you have expired normally (ERV + RV
What is VC
Vital Capacity (VC) is the max amount of air you can move into or out of lungs = ERV + VT + IRV
What is TL
Total Lung Capacity (TL) is the total volume in lungs = VC + RC
What is an energetically expensive breathing pattern with maximum alveoli ventilation
High tidal volume and low frequency
What is an energetically inexpensive breathing pattern with low alveoli ventilation
High frequency and low tidal volume
What are the 3 factors that lung compliance is dependent on?
Pulmonary connective tissue changes - damage to alveolar (emphysema), also get fibrosis of the lung which makes it stiff Surfactant Thoracic cage mobility
What are the two types of energetic cost
elastic cost - - Elastic resistance of lung tissue and chest wall friction cost - frictional resistance to gas flow through the airways
In which situations will the cost of ventilation increase
- Tidal volume increases - E.g. during exercise 2. Compliance decreases - If there is a decreased amount of surfactant 3. Increase airway resistance (bronchoconstriction) - Increased connective tissue from scarring - Decreased thoracic mobility
What type of breathing pattern will a patient with stiff lung adopt?
- As the body tried to minimise this energetic cost, it tends to adopt a high frequency and low tidal volume pattern to minimise the cost of breathing as the elastic cost that would be incurred is far too great
What type of breathing pattern will a patient with narrow airways adopt?
- Every time they drag air in or out of the airways, its difficult and costly for the body, thus patients tend to adopt a low frequency and high tidal volume breathing pattern in order to minimise the total cost of breathing
Describe the 4 steps of the CO2 in the oxygen cascade
- CO2 movements the opposite of the oxygen cascade;
- Diffusion of CO2 (a by-product of the TCA cycle) from the mitochondria into the blood
- Circulation of blood (via the venous system)
- Diffusion of CO2 from the blood into the lungs
- Expiration of air from the lungs (breathing it out of the body)
Describe the 4 steps of the oxygen cascade
- Aspiration of air into the lungs (through negative pressure)
- Diffusion of oxygen from air into red blood cells (binding it to the haemoglobin)
- Circulation of red blood cells around the body (where CVM comes in)
- Diffusion of oxygen from red blood cells into the mitochondria (wherever the working cell is)
Fill the blanks
If the negative pressure of the pleura in the lungs is lost, therefore the lungs won’t move with it but the chest moves when taking a breath. What is the term for this?
Pneumothorax
Why does sleep apnoea increase the risk of motor whicle and workplace accidents?
Obstructive sleep aneoa = partial/complete temproarily blockage of upper airway during sleep (this is from your throat muscles relaxing)
Apnoea will cause a decrease in the Haemoglobin oxygen saturation
This triggers arousal from REM sleep - as your body is trying to breath
Repeated arousal disrupts REM sleep
Why are sleep anoea and obesity a viscous cycle?
Obseity can result in narrowing of the upper airways due to increased pressure on upper airways from additional surrounding adipose tissue. Obesity also leads to preference of sleeping on your back. This increases snoring as your tongue then partially occludes your upper airways.
obstructive sleep apnoea induced sleep fragmentation and intermittent hypoxia are linked to insulin resistance.
This is because excessive daytime sleepiness and fatigue increase your preference for aclorie dense and sugary food –> leads to obesity –> increases severity of obstructive sleep apnoea.
What is the formula for minute ventilation
VE= VT x f
What is the formula for FRC
FRC = (CiHe/CfHe - 1)* Vispir
CIHe is the inital concentration of helium in the spirometer
CfHe is the final concentration of helium in the spirometer
Vispir is the initial volume of the spirometer
