Respiratory Week 4 Flashcards
What is cellular respiration
Intracellular metabolic reaction that uses O2 and produce CO2 during ATP production
What is external respiration
Transfer of O2 and CO2 between external environment and tissue cells
Which 2 systems work together to accomplish external respiration
Respiratory and circulatory systems
What are the functions of the respiratory system
Metabolism
Acid-Base regulation
Endocrine function
Immunological function
Voice production by larynx
How does respiratory system regulate the acid-base
Removes CO2 and regulate pH (H+ ions) which are by products of metabolism
What is the clinical significance of respiratory system
Treatment of respiratory diseases (asthma, pneumonia, COVID)
Ventilation in anaesthesized and ICU patients
Smoker lungs
Emphysema
What is the issue associated with emphysema
Shortness of breath as a result of alveolar surface destruction which leads to lower surface area of O2 and CO2 exchange
How does respiratory system activate its endocrine function
It activates angiotensin II which causes greater fluid retention, greater fluid intake and increased BP and blood volume
How does respiratory accomplish its immunological function
It clears irritants and potential pathogens
What is the anatomical relationship between heart and major arteries
Aorta is involved in systemic circulation
Pulmonary trunk w/ L&R arteries is involved in pulmonary circulation
What are the components of respiratory airways
Upper RS
- larynx
- pharynx
- nasal passages
Lower RS
- trachea
- R&L Bronchi
- Bronchioles
- Alveoli
Functional relationship between respiratory system and circulatory system
- Deoxygenated blood from systemic circulation enters heart
- Deoxygenated blood leaves heart through pulmonary arteries to lungs
- Blood is oxygenated and CO2 released in lungs
- Oxygenated blood re-enters heart via pulmonary veins
- Distributed to rest of body via aorta and branches
What are alveoli known as
Sites of gas exchange
Where does the conducting zone begin and end
Trachea to terminal bronchioles (0-16 division)
Where does transitional and respiratory zone begin and end
From respiratory to alveolar sacs (17 - 23 divisions)
Why should we not assume the conducting and respiratory zones are as such
Varies with population, age and many other factors as respiratory zone could start from 15 division onwards
How many alveolar sacs are there
300 - 500 million alveoli
What does the visceral pleura line
Lungs
What does the parietal pleura line
Chest wall and diaphragm (inner thoracic wall)
What is the function of diaphragm besides inspiration and expiration
Separates thorax from abdomen
What is pleural space known as
Potential space
What is the issue if pleural cavity filled with excess fluid
Pleural effusion
- due to fluid leaking from capillaries
- increased hydrostatic pressure
What is the issue if the pleural cavity is filled with excess air
Pneumothorax
- Due to lung puncture/collapse
What is the issue faced if excess fluid and air enter pleural cavity
Disrupts air movement in/out of lungs
What are the 3 important pressure considerations in lungs
- Atmospheric pressure
- Intra-alveolar pressure
- Intrapleural pressure
What is the atmospheric pressure
760 mmHg at sea level
What is the intra-alveolar pressure
Varies with ventilation
What is the intrapleural pressure
Normally 756mmHg
What is the difference between trachea-bronchi and bronchi-terminal bronchioles
Trachea-Bronchi = mainly cartilage, little smooth muscle
Bronchi-Bronchioles = mainly smooth muscle
What are bronchi - bronchioles innervated by
autonomous nervous system
- sympathetic = bronchodilation
- parasympathetic = bronchoconstriction
What happens for people with asthma
Excessive bronchoconstriction
How is asthma treated
Beta2 - adrenergic receptor agonist bronchodilator
How does the treatment for asthma work
Relaxes smooth muscle in airways which allows air to flow in/out of lungs easier
What allows bronchi-bronchioles to constrict and dilate
Smooth muscle
What is ventilation
Movement of air in/out of respiratory tract
What property allows chest wall and lungs to expand and recoil
Elastic structures
What law do the lungs and air obey
Boyle’s Law
Does all the inspired air undergo gas exchange within blood
No
What is the difference between physiological and anatomical dead space
Physiological - Volume of air that doesn’t exchange with blood
Anatomical - Air filled conducting airways that does not participate in gas exchange
What is alveolar ventilation
Volume of air that reaches alveoli per min
How is alveolar ventilation calculated
(Tidal vol - Anatomical dead space) x breaths per minute
What are the protective mechanisms of airways
Protecting respiratory epithelium mucosa
Protecting lungs
How is respiratory epithelium protected
Mucous secretion and humidification of air in upper passages
How are lungs protected
Alveolar macrophages ingest particles/pathogens when reaching lung
Airway reflexes - Sneeze, cough, epiglottis closes glottis when swallowing
Ciliary elevator
- Moves particles trapped by mucus away from lungs
Mucociliary trapping
What does defective ciliary movement result in
Lung infections
What does the epithelium of upper airways to trachea, bronchi, bronchioles have
Cilia and mucous
What do the respiratory skeletal muscles do during inspiration and expiration
Increase side to side dimension of thoracic cavity
Increased vertical dimension of thoracic cavity
Increased anterior-posterior dimension of thoracic cavity
Which direction does sternum move upon rib elevation
upwards and outwards
What is the difference between inspiration and quiet expiration
Inspiration is active whereas quiet expiration is passive
How far is the barrier separating air and blood
0.5 micro meters
What is the contact travel time between blood in capillaries and alveolus
0.75s
At rest, how long does it take for blood to be fully oxygenated
0.25s
How does gas exchange occur across the barrier between air and blood
Diffusion; From high to low concentration
What is constant regardless of inspiration and expiration
Transmural pressure gradient and lung is always stretched to some degree
When ventilation is stimulated, what changes occur
Increased inspiratory effect
- increased lung vol
- increased air drawn into lungs per unit time
Increased expiratory effect
- increased air expelled from lungs per unit time
- decreased lung vol
Is transmural pressure gradient always present
Yes
Is lung always stretched regardless of inspiration and expiration
Yes
At the end of inspiration and expiration, is intra-alveolar pressure = atmospheric pressure
Yes, airflows continues until both pressure equilibrate
During inspiration, intra-alveolar pressure > atmospheric pressure?
False. Intra-alveolar pressure < atmospheric pressure
During expiration, intra-alveolar pressure > atmospheric pressure
True
What is transmural pressure gradient
Difference between intra-alveolar pressure and intra-pleural pressure
What is the process of airflow during inspiration
Inspiratory muscles contract > thoracic cavity expands > intrapleural pressure becomes negative > transmural pressure becomes negative > lung inflates > intra-alveolar pressure becomes subatmospheric > airflow until alveolar pressure = atmospheric pressure
What is the difference between inspiration and quiet expiration
Airflow in inspiration is active whereas airflow in quiet expiration is passive
