Respiratory Flashcards
Inspiration
Downward contraction of diaphragm
Upward and Outward movement of the ribs due to contraction of external intercostal muscle
Expiration
Is passive driven by elastic recoil of the lungs
What is the gas exchange unit of the lung
Acinus
Acinus composed of
Barnching respiratory bronchioles and clusters of alveoli
Most smallest area in the respiratory tract
Glottis and trachea
Type 1 pneumocyte
√ Flattened epithelial cells
√ Lining of alveoli
Type 2 Pneumocytes
√ Fewer than type 1
√ Produce surfactant
√ Can divide to reconstitute type 1 pneumocyte after lung injury
Surfactant
√ Mixture of phospholipid
√ Reduce surface tension
√ Counteract the tendency of the alveoli to collaps
How maximum respiratory volume is limited by lung
Elastin fibers allow the lung to be easily distended at physiological lung volume. But collagen fibres cause increasing stiffness as full inflation is approached
Small airway patency is maintained by
Elastin fibre in alveolar wall by radial traction on the airway walls
Calculation of alveolar ventilation
AV= (tidal volume - dead space) × Respiratory rate
Gas exchange occurs by
Alveoli which are connected to each other
by the pores of kohn
Acinus
The unit of lung supplied by a terminal bronchiole
Pulmonary artery
Bronchial artery
PA carries desaturated blood
BA Systemic supply to airway tissue
What is the origin of the respiratory cycle
Respiratory neuron in the posterior medulla oblongata
Control of breathing modulated by
√ Central chemoreceptor in the ventrolateral medulla senses pH in the CSF and stimulated indirectly by a rise in the arterial Pco2
√ Carotid bodies sense hypoxemia mainly activated by arterial Po2 value less than 8kpa (60mmHg)
√ Muscle spindles in respiratory muscle
√ Vagal sensory fibres in the lung stimulated by stretch, inhaled toxins, disease process in interstitium
√ Cortical (Volitional) and limbic ( Emotional) influences
Disease occurring due to defective mucociiary transport
√ Cystic fibrosis
√ Primary ciliary dyskinesia
√ Young syndrome
Which are characterised by repeated sino-pulmonary infections and bronchietesis
Airway secretions contains
√ Antimicrobials peptides such as defensins and lysozyme
√ IgA
√ Antiproteinase
√ Anti oxidant
Premature emphysema associated with which deficiency
alpha 1 antitrypsin which regulates neutrophil elastase
What is the investigation of choice for pulmonary thromboembolism
CT Pulmonary Angiography (CTPA)
Indication of High CT
- Diffuse Parenchymal Lung Disease
- Identifying airway thickening
- Bronchiectasis
- Emphysema
FDG PET indication
✓ Staging of mediastinal lymph nodes & distal metastatic disease in lung cancer
✓ Investigation of pulmonary nodules
✓ Differentiate benign from malignant pleural disease
✓ Extent of extrapulmonary disease in sarcoidosis
Causes of consolidation on CXR
Inflammation
Infection
Infarction
Bronchoalveolar cell carcinoma
Causes of Multiple Nodule on CXR
Miliary Tuberculosis
Dust inhalation
Metastatic malignancy
Healed Vericella Pneumonia
Rheumatoid arthritis