Intro Flashcards
Parts of the upper respiratory tract
Nasal passage
Turbinates
Parasinal sinuses
Pharynx
- nasopharynx
- oropharynx
- laryngopharynx
Larynx
Turbinates
Boney projections that warm, moisten and filter air/pathogens
Parasinal sinuses
Small cavities/openings that add resonance to voice
Larynx content and function
Consists of cartilage and muscle
- hyoid, thyroid and cricoid ligament
Contains epiglottis and vocal chords
Involved in breathing, producing voice and preventing aspiration
Epiglottis during breathing, coughing and eating
Open during breathing so air goes into tranche
Closed during eating so food into esophagus
With coughing it closes to increase abdominal pressure then opens up to release cough
Lower respiratory tract
Trachea
Right and left primary bronchi
Secondary and tertiary bronchi
Bronchioles
Alveoli
Trachea anatomy and function
Connects larynx to bronchi
12cm long
From cricoid cartilage to carina at T5/sternal angle
Cartilage supports wall and prevents airway collapse
Angle of left vs right bronchi
Left: 45-55
Right: 20-30
How do Alveoli enable gas exchange
Create large SA
Coated with surfactant which reduces surface tension allowing inspiration and preventing collapse
Collateral ventilation
Ventilation of alveolar structures through passages that bypass normal airways
- interbrincholar channel of martin
- bronchiole alveolar channel of lambert
- interalveolar pore of Kohn
- interlobar via fissures
Right lung surface anatomy
3cm above clavicle at midclavicular line
Follows R parasternal line
Ends at 6th rib parasternal line at midclavicular line, 8th rib mid axillary line and 10th rib posteriorly
Left lung surface Anatomy
Markings
3cm above clavicle in midclavicular line
Follows L parasternal line
Ends at 6th rib mid clavicular line, 8th rib mid axillary line and 10th rib posterior (lateral to vertebral line)
Surface anatomy of fissures
Oblique: T2 Spinous process to 6th coastal cartilage anteriorly
Horizontal: extends from oblique fissure to 3rd or 4th rib
Right upper lobe segments
Apical
Anterior
Posterior
Right middle lobe segment
Medial
Lateral
Right lower lobe segments
Superior
Medial
Lateral
Anterior
Posterior
Left upper lobe segments
Apical
Anterior
Posterior
Lingula
Left lower lobe segments
Superior
Anterior
Lateral
Posterior
Pressure inside pleural cavity
Negative pleura holds the visceral and parietal pleura close together and promote lung expansion
Diaphragm role
Primary inspiration muscle
Postural stability
Vascular and lymphatic system role
Supports gastroesohageal function
3 openings of diaphragm
T8 - IVC, R phrenic N
T10 - esophagus, anterior and posterior vagal trunk
T12 - thoracic duct and aorta
Respiratory defense mechanism
Respiratory mucosa
Mucociliary transport
Cough
Airflow is ___ proportional to airway resistance and ___ related to pressure difference
Inversely, proportionally
Inspiration mechanism
Contraction of diaphragm and external intercostal
Diaphragm flattens and descends while ribs rise
Decreased pressure in pleural cavity, alveoli and airway
Decreased thoracic pressure < atmospheric pressure leads to inspiration
Expiration mechanism
Diaphragm and external intercostal relax causing thorax size to decrease
Natural recoil of alveoli
Increased intra alveolar pressure causes passive expiration
Control to ventilation
- Medullary respiratory center
- ventral group: control rhythm and respiratory rate
- dorsal: stimulates inspiration via phrenic nerve and intercostal nerve to diaphragm and intercostal (stimulates forced expiration when needed) - Potine respiratory center
- Higher brain centers
- Peripheral chemoreceptors (respond to 02)
- Central chemoreceptors (respond to CO2)
- Muscle joint receptors
- Stretch and irritant receptors in lungs
- External factors (e.g. drugs)
Trigger of respiration
Elevated CO2 diffuses into CSF and Lowers pH —> stimulates respiratory center —> increased RR and depth
O2 levels have a large reserve and need a large decrease for peripheral chemoreceptors to kick in
Factors affecting diffusion
Pressure gradient
Thickness of respiratory membrane
Surface area
Inspiration reserve volume
Maximal volume of air inspired in excess of normal tidal volume
Expiratory reserve volume
Maximal volume of air expired following tidal expiration
Vital capacity
Maximal amount of air expired following maximal inspiration
Total lung capacity
Total volume of air in lungs after maximal inspiration
What is the Dependent lung and how is it created
Pleural pressure is more negative as you go down due to weight of lung and pressure of mediastinal and abdominal content.
This causes top of lung to have larger and inflated alveoli (not compliant)
Dependent lung: When the alveoli are small and compressed creating a compliant portion in the lung of the volume-compliance curve and more alveolar ventilation
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West zones
Difference in pressure across the lung result in distinct areas of lung perfusion
Zone 1, where alveolar pressure is higher than arterial or venous pressure —> collapse of alveolar vessels —> no ventilation (lots of alveolar dead space)
Zone 2, balance between alveolar and arterial pressure determines blood flow
Zone 3, where both arterial and venous pressure is higher than alveolar —> capillaries distend and increases air exchange.Blood flow is highest here . Similar to dependent lung (zone 3 is healthy part of lung)
V/Q ratio in west zones
> 1 : zone 1 with excellent ventilation but poor blood flow
<1: zone 3 with excellent blood flow but poor ventilation
1: zone 2 (~.8) well matched gas and blood flow
0: no airflow/obstruction
Obstructive vs restrictive
Obstructive: reduction in airflow and difficulty exhaling
Restriction: reduction in lung volume, difficulty inhaling
