Within the thoracic and abdominal cavities there are 3 serous mesodermal derived membranes which form a covering for the:
Lungs (pleura)
Heart (pericardium)
Abdominal viscera (peritoneum)
Double-layered membranes permits friction reducing movements
Lined by mesothelium
Parietal layer vs Visceral layer Pleura Innervation of Pleura Parietal pleura has extensive somatic sensory innervation
The intercostal nerves supply the costal and peripheral portions of the diaphragmatic pleura.
The phrenic nerve supplies the central portion of the diaphragmatic pleura and the mediastinal pleura.
The visceral pleura is supplied by visceral sensory nerves that course with the autonomic nerves
Pleural cavity Contains a small amount of serous fluid that lubricates the opposing parietal and visceral layers.
Pleural Reflections there are 2 rib interspaces separating the inferior limit of parietal pleural reflections from the inferior border of the lungs and visceral pleura between:
ribs 6–8 in the midclavicular line
ribs 8–10 in the midaxillary line
ribs 10–12 in the paravertebral line
Open pneumothorax Air enters the pleural cavity following a penetrating wound of the chest cavity.
Air moves freely through the wound during inspiration and expiration.
During inspiration, air enters the chest wall and the mediastinum will shift toward other side and compress the opposite lung.
During expiration, air exits the wound and the mediastinum moves back toward the affected side.
Tension pneumothorax Piece of tissue covers and forms a flap over the wound.
During inspiration, air enters the chest cavity, which results in a shift of the mediastinum toward the other side, compressing the opposite lung.
During expiration, the piece of tissue prevents the air from escaping the wound, which increases the pressure and the shift toward the opposite side is enhanced.
This severely reduces the opposite lung function and venous return to the heart and can be life-threatening.
Symptoms: Air hunger
Chest pain
Trachea deviation
Absent breath sounds
Hyper resonant percussion
Jugular venous distention
Tachycardia
Hypotension
Lungs
Lobes and Fissures The right lung is divided into 3 lobes (superior, middle, inferior) separated by 2 fissures, the horizontal and oblique fissures.
The left lung is divided into 2 lobes (superior, inferior) separated by an oblique fissure.
The lingula of the upper lobe of the left lung corresponds to the middle lobe of the right lung.
The oblique fissure of both lungs projects anteriorly at approximately the 5th intercostal space
Clinical Correlate The superior lobe of the right lung projects anteriorly on the chest wall above the 4th rib and the middle lobe projects anteriorly below the 4th rib.
A small portion of the inferior lobe of both lungs projects below the 6th rib anteriorly but primarily projects to the posterior chest wall.
Clinical Correlate Aspiration of a foreign body will more often enter the right primary bronchus, which is shorter, wider, and more vertical than the left primary bronchus.
When the individual is vertical, the foreign body usually falls into the posterior basal segment of the right inferior lobe.
Horizontal position aspiration Lymphatic Drainage Exception: CNS
Respiratory histology
The enzyme that converts angiotensin I to angiotensin II is produced by the lung endothelial cells.
Trachea Bronchi Pulmonary neuroendocrine (PNE) cells are comparable to the endocrine cells in the gut.
APUD cells (Amino-Precursor-Uptake-Decarboxylase), DNES cells (DiffuseNeuro EndocrineSystem) and K (Kulchitsky) cells.
Clara cells
Non ciliated
Detoxification of airborne toxins
Stem cell for the ciliated cells
Clara cells increases in response to increased levels of pollutants like cigarette smoke
Clara cells are most abundant in the terminal bronchioles, where they make up about 80% of the epithelial cell lining
Also involved with chloride ion transport into the lumens of the terminal bronchioles
CFTR located on Clara cells?
Where is Clara? Type I pneumocyte Represent only 40% of the alveolar lining cells
Cover 90–95% of the surface
Involved in gas exchange
Post-mitotic
Type II pneumocyte form only 5–10% of the surface
Produce and secrete surfactant
Stem cells for themselves and the type I cell
Round cells with “myelin figures” in their apical cytoplasm which represent the remnants of surfactantafter histological processing
Surfactant main component?
What does contain HF cells?
