Flashcards in Week 3 Resp Deck (72):
Describe the 4 main steps of the oxygen cascade
1.Aspiration of air into lungs
2. Diffusion of oxygen from the air into the red blood cells
3. Circulation of red blood cells around the body
4. Diffusion of oxygen from the red blood cells into the mitochondria for cellular use ( TCA cycle)
Describe the 4 main steps of the carbon dioxide movement
1. Diffusion of carbon dioxide from the mitochondria to the blood
2. Circulation of carbon dioxide in blood
3. Diffusion of carbon dioxide from blood to lungs
4. Expiration of air with carbon dioxide from lungs
What is pulmonary ventilation?
The physical movement of air into and out of the lungs
What components make up the conducting zone of the respiratory system?
Trachea, bronchi, bronchioles, nose, mouth, nasopharynx
What components make up the respiratory zone of the respiratory system?
Respiratory bronchioles, alveolar ducts, alveoli
What are the main roles of the conducting zone?
Conduct, warm, cleanse and humidify the air. Allow movement of air to alveoli. NO gas exchange
What are the main roles of the respiratory zone?
Breathing directly into trachea (tracheostomy) results in what?
Cooling and drying of the respiratory membranes and serious lung crusting and infection.
What is another name for nasal conchae and what is their role with filter and particle deposition?
Nasal turbinates- creates turbulence which helps deposit particles in the nose. It also reduces respiratory water and heat loss.
What sized particles can enter the lungs?
What is airway patency?
Keeping the airways open to promote movement of air
What structures assist with airway patency?
Trachea- cartilage rings
Bronchi- less extensive cartilage plates
Bronchioles- pressure gradients and radial traction with collagen and least in fibers from the surrounding tissues(lung parenchyma)
List two things that can occur due to problems with upper airway patency
Snoring and sleep apnoea
List two things that can occur due to problems with lower airway patency
Obstructive lung disorders such as emphysema or asthma
List a problem than can occur with alveolar patency?
Infant respiratory distress syndrome (lack of surfactant in premature babies)
How is pressure created in the respiratory system?
By molecules of air colliding with the walls of their container and with eachother
What is boyles law?
Inverse relationship between gas volume and pressure.Gasses move form areas of high pressure to areas of low pressure
Why is the lung pleura essential for normal airflow?
Sucks the lungs out towards the chest wall and keeps the lungs moving with the chest wall. Negative intrapleural pressure helps to keep lungs patent
What is a pneumothorax?
Accumulation of air in the pleural cavity.Can be penetrating or non penetrating or spontaneous. It restricts lung expansion
What is the normal intrapleural pressure? In mm Hg
Which direction to the lungs and ribs naturally want to recoil?
Ribs want to recoil outwards and lungs want to recoil inwards (collapse)
Define transmittal pressure
Pressure across the airway wall or across the lung wall
Describe what happens during inhalation
Diaphragm contracts and moves inferiorly. External intercostal contract and move ribs upward and out. Thoracic cavity increases, pressure decreases and air flows in.
Describe the process of expiration.
Elastic recoil of lung tissue when muscles relax. Decrease in lung volume and increased lung pressure. Air flows out.
Why is expiration normally passive?
It is passive as no energy is required, uses elastic recoil of ribs and lungs
What is normal atmospheric pressure
What is intrapulmonary pressure during inhalation?
759mmHg as pressure has decreased allowing for air to rush in
What is normal intrapulmonary pressure during exhalation? (In mmHg)
761mmHg as pressure has increased in lungs and air is now rushing out to lower conc.
Goes intrapleural pressure become more or less negative upon inspiration?
List the two main muscles involved in inspiration and what type of process this is?
Diaphragm and external intercostals. Active process as it requires energy to contract the respiratory muscles
List the 3 main muscles involved in forced expiration and what type of process this is?
Abdominal muscles, internal intercostals and innermost internal intercostals. Active, uses muscles to increase speed of air leaving the lungs uses energy
Describe quiet breathing.
Also called eupnea/ normal breathing. Inspiration involves diaphragm and external intercostals in varying degrees. Expiration is passive with elastic recoil
Describe forced breathing
Active expiration using internal intercostals and abdominal muscles. Inspiration involves diaphragm, external intercostals and accessory respiratory muscles.
Increase in breathing via rate or depth of both
Increase in ventilation above predicted metabolic rate (over breathing)
Is an increase in breathing seen in running hyperpnoea or hyperventilation?
Hyperpnoea. Breathing is increased to match increase in metabolic rate
Define tidal volume
The amount of air inhaled in one breath at rest ~500mL
Define respiratory rate (f)
Number of breaths per minute
What term means the amount of air MOVED each minute?
Approximately how much air in mL stays in the conducting zone and does not participate in gas exchange?
Define dead space (Vd)
Amount of air in conducting zone
What is alveolar ventilation?
Amount of air reaching alveolar each minute
How do you measure ventilation?
By using spirometry
How many respiratory volumes are there?
Define expiratory reserve Volume ERV
Amount of additional air than you can force out of your lungs after you have expired normally (~1000mL)
Define inspiratory reserve Volume IRV
Amount of additional air that you can inhale after you have inhaled normally (~1900-3300mL)
Define residual volume RV
Amount of air left in lungs after a maximum expiration (you can't fully empty your lungs) (~1100mL)
Define inspiratory capacity (IC)
Amount of air that you can draw into your lungs after you have completed a normal expiration (tidal volume + IRV)
Define functional residual capacity FRC
Amount of air remaining in the lungs after you have expired normally. ERV +RV
Define Vital Capacity? (VC)
Max amount of air you can move into and out of the lungs? (ERV + VT + IRV)
Total lung capacity TLC
Total volume in lungs VC+ RV
Ease of expansion of lungs
Does a lung with high compliance or low compliance require greater pressure to achieve the same change in volume?
Low compliance (stiff lung). Need to recruit more muscles to create a greater negative intrapulmonary pressure. More energetically costly
What does lung compliance depend on?
Pulmonary connective tissue
Thoracic cage mobility
At rest, how much of the bodies energy demands does ventilation represent?
Finish this sentence : cost (energetic cost) of ventilation increases when....
Tidal volume increases, compliance decreases, increase in airway resistance occurs
What is airflow resistance work associated with?
The friction that air encounters as it travels down the airways
What is elastic work of breathing associated with?
An increase in volume of thoracic cavity (diaphragm and muscle activity) increases elastic cost
What happens to work of breathing if lung compliance decreases?
Elastic cost of breathing increases, increasing tidal volume becomes costly, patients at rest tend to adopt high rate and low tidal volume breathing to minimise costs of breathing
What happens to work of breathing if airways narrow/ airway patency decreases?
Airflow resistance increases, increasing rate of breathing becomes costly , patients at rest tend to adopt low rate and high tidal volume breathing to minimise costs of breathing
Why are apnoeas in an obstructive sleep apnoea patient only present during sleep and not when they are awake?
Activity of upper airway dilator muscles is reduced during sleep which increases the tendency for upper airways of narrow during sleep. When asleep on back, tongue and soft palate may fall back into upper airway causing partial blockage (and snoring)
How does CPAP help with OSA patients?
CPAP pushes air into the upper airways. The positive pressure keeps the airway from collapsing where activity of the upper airway dilator muscles are reduced during sleep.
What formula can be used to predict vital capacity?
What formula can be used to predict total lung capacity?
What formula can be used to predict residual volume?
RV = VC x factor
Name the 3 factors for predicting residual volume
What is the most common cause of daytime sleepiness
Obstructive sleep apnoea
How many people with a BMI over 30 had obstructive sleep apnea
For apnoea to be considered clinical important, how many times per hour
Lasting longer than 10 seconds and occurring more than 5 times per hour
List some treatment options for sleep apnoa
Weight loss, surgery, dental appliances or breathing assistance (eg CPAP)
What is central sleep apnoea often a consequence of?
Vascular disease (eg stroke)