Lungs and Airway Anatomy Flashcards
Composition of Air
Nitrogen N2 : 78% Oxygen O2 : 21% Argon Ar : 0.9% Carbon Dioxide CO2 : 0.04% \+ Others
Atmospheric Pressure at rest
760 mmHg
Intrapulmonary Pressure at rest
760 mmHg
Intrapleural Pressure at rest
756 mmHg
Negative pressure
Respiration
Production of ATP from organic molecules.
Aerobic respiration requires oxygen. That’s where ventilation and gas exchange come in.
Ventilation
Ventilation is the process by which air moves into and out of the lungs and is made available for gas exchange across the alveolar-capillary membrane.
Control of Ventilation
Primarily involves neurons in the medulla and pons.
Medulla: sets the respiratory rhythm
Pons: influences and modifies the activity of the medullary neurons.
Aerobic Respiration
Takes place in the mitochondria and requires oxygen and glucose, and produces carbon dioxide, water and energy.
The chemical equation is:
C6H12O6 + 6O2 → 6CO2 + 6H20
Extra Thoracic Tract
Upper respiratory tract
- Mouth
- External nose
- Nasal cavities
- Paranasal sinuses
- Pharynx
- Larynx (above focal cords)
External Nose
Olfactory and respiratory organ.
Resonator of voice.
Bone, cartilage and fibro-fatty tissue.
The Nose
Nasal vestibule: - Hair + skin (incl muscles) Mucous membrane: - Goblet cells - Filter particulate matter - Adjust temp and humidity of inspired air.
Nasal Cavities
3 Layers (openings): - Superior concha - Middle concha (very thick mucosa: cold) - Inferior concha Olfactory region: Superior concha Respiratory region: Middle and inferior concha 4 pathways Increased surface area Turbulent airflow Humidification
Pharynx
Forms a continuous muscular passage for air, food, and liquids to travel down from your nose and mouth to your lungs and stomach.
3 parts:
Nasopharynx - posterior to the nasal cavity
Oropharynx - posterior to the oral cavity
Laryngopharynx - posterior to the larynx
Mucosal Features (Pharynx)
- Mucous membrane
- Muscular layer
C5-C6!
Larynx
Located between pharynx and trachea (C3-C6)
9 Cartilage pieces
Respiratory mucosa
Controls voice (voice box) and air guidance
Recurrent laryngeal nerve (branches vagus nerve)
Superior/inferior laryngeal artery
Larynx Cartilage
Unpaired: - Thyroid - Epiglottis - Cricoid Paired: - Arytenoid - Corniculate - Cuneiform
Intrathoracic Tract
Lower tract or thoracic airway.
Complex series of branching tubes that culminate in the gas exchanging area.
Tracheobronchial tree.
Tracheobronchial Tree
- Trachea
- 2 main bronchi
- Lobar bronchi
- Segmental bronchi
- Terminal bronchioles
- Respiratory bronchioles
- Alveoli
Conducting Zone of the Thoracic Airway
- Trachea
- 2 main bronchi
- Lobar bronchi
- Segmental bronchi
- Terminal bronchioles
Respiratory Zone of the Thoracic Airway
- Respiratory Bronchioles
7. Alveoli
Trachea Composition and Size
Tube composed of: - 16-20 tracheal cartilages C-shape - Annular ligaments - Membranous posterior wall - Mucosa (upper respiratory tract) Size: - 10-14 cm long - 1,6-1,8 cm wide
Respiratory Epithelium
Goblet cells: Column shaped, produce mucus. Destroy bacteria/viruses. Captures dust and chemicals.
Cilia: Microscopic projections that look like tiny hairs. Organized transport of mucus (12 beats/sec). Pharynx (swallowing), stomach.
Bronchioles Composition - Cells
No cartilage or goblet cells.
Club cells - Produce SURFACTANT
Alveoli Composition and Size
Thin-walled air sack \+/- 400 million by lung 0,2 mm expiration 0,5 mm inspiration Respiratory bronchioles, alveolar ducts, and alveolar sacs → Alveoli Respiratory part used for gas exchange. Surfactant.
Blood-Air Barrier
Gas exchange region:
Inspiration → O2 from alveoli goes across barrier to enter in the blood flow and bind to hemoglobin.
CO2 leaves the blood flow and enters the alveoli → Expiration.
What happens to the diaphragm and lungs during inspiration? (volume, pressure)
Diaphragm contract and becomes flat.
Lung volume increases.
Lung pressure (O2) decreases.
Atmospheric pressure is higher than lung pressure.
Air (O2) enters lungs from high pressure to low.
Lungs Composition and Shape
Gray to blush-pink Cone shaped Right lung: - 3 lobes - Heavier Left lung: - 2 lobes - lighter - irregular shape
Hilum
Place at which main bronchi + pulmonary arteries and veins enter the lungs.
Hilum Location
On the center of mediastinal surface of the lung and behind the cardiac impression.
Meeting point between parietal and visceral pleura.
Structures of the Hilum of the Left Lung
- Left pulmonary artery
- Left superior pulmonary vein
- Superior and inferior lobar bronchi
- Left inferior pulmonary vein
- Pulmonary lymph nodes
Structures of the Hilum of the Right Lung
- Superior lobar bronchus
- Middle and inferior lobar bronchus
- Right pulmonary artery
- Right superior pulmonary vein
- Right inferior pulmonary vein
- Pulmonary lymph nodes
Pulmonary Ligament - Hilum
Not a ligament but a reflection of the mediastinal parietal pleura.
Fusion between the parietal mediastinal pleura and the visceral pleura.
Function:
- Hold the lower part of the lungs in position.
- Allow expansion of pulmonary veins
Wall Structure of Trachea, Two Main Bronchi and Lobar Bronchi
Hyaline cartilage, smooth muscle, elastic fiber.
Wall Structure of the Segmental Bronchi and Bronchioles
Smooth muscle and elastic fiber.
Right Lung Lobes
Superior, middle and inferior.
Divided by fissures, horizontal and oblique.
Oblique fissure separates inferior lobe form superior and middle lobes so that the inferior lobe is posterior and inferior to the fissure.
Horizontal fissure separates the middle and superior lobes, horizontally from the edge to the hilum.
Left Lung Lobes
Divided into superior and inferior lobes by the oblique fissure
Right Main Bronchus Division - Right Superior Lobar Bronchus
Apical segmental bronchus (I)
Posterior segmental bronchus (II)
Anterior segmental bronchus (III)
Right Main Bronchus Division - Right Middle Lobar Bronchus
Lateral segmental bronchus (IV)
Medial segmental bronchus (V)
Right Main Bronchus Division - Right Inferior Lobar Broncus
Superior segmental bronchus (VI) Medial basal segmental bronchus (VII) Anterior basal segmental bronchus (VIII) Lateral basal segmental bronchus (IX) Posterior basal segmental bronchus (X)
Left Bronchus Division - Left Superior Lobar Bronchus
Apicoposterior segmental bronchus (I, II)
Anterior segmental bronchus (III)
Superior lingular segmental bronchus (IV)
Inferior lingular segmental bronchus (V)
Left Bronchus Division - Left Inferior Lobar Bronchus
Superior segmental bronchus (VI) Medial basal segmental bronchus (VII) Anterior basal segmental bronchus (VIII) Lateral basal segmental bronchus (IX) Posterior basal segmental bronchus (X)
