Lungs - the thorax Flashcards
Parietal pleura
A mesothelial membrane lining the inner surface of the thoracic wall, diaphragm, and mediastinum
Visceral pleura
The pleura reflected from the mediastinum onto the lungs, covering their outer surface
Pleural cavity
A potential space between the parietal and visceral pleura, containing a small amount of pleural fluid
Pleural fluid
Lubricates the pleural surfaces, reducing friction during respiration.
Pleural effusion
Excess accumulation of pleural fluid in the pleural cavity, which can compress the lung and impair respiration
Pneumothorax
the presence of air in the pleural cavity, which can cause lung collapse
Pleuritis
Inflammation of the pleura, often leading to pleuritic pain due to irritation of the parietal pleura, which is innervated by intercostal and phrenic nerves.
Lobes of lung
Right lung: Three lobes (superior, middle, and inferior)
Left lung: Two lobes (superior and inferior)
Fissures of lung
Oblique fissure: present in both lungs, separates the superior and inferior lobes
Horizontal fissure: present only in the right lung, separates the superior and middle lobes.
Hilum of lung
The root of the lung, where the bronchi, pulmonary arteries, pulmonary veins, bronchial vessels, lymphatics, and nerves enter and exit.
Alveoli
Small air sacs at the terminal end of the bronchial tree, responsible for gas exchange
Bronchial tree
a branching system of airways, beginning at the trachea and dividing into progressively smaller airways.
Pleural effusion anatomical basis
Hydrothorax & Hemothorax
Hydrothorax
Accumulation of serous fluid in the pleural cavity
Hemothorax
Accumulation of blood in the pleural cavity, often due to trauma affecting intercostal or internal thoracic vessels.
Pneumothorax anatomical basis
Occurs when air enters the pleural cavity, leading to lung collapse.
Can result from penetrating chest trauma, spontaneous rupture of lung blebs, or mechanical ventilation injury.
Respiratory muscles
Diaphragm: primary muscle of respiration
Intercostal muscles: Support rib cage and aid in breathing
Accessory muscles: Assist in forced respiration (scalene muscles, sternocleidomastoid, abdominal muscles)
Goblet cells
Specialized mucus-producing cells found in the epithelium of the airways.
Ciliated epithelium
Pseudostratified columnar epithelium with cilia lines the trachea and bronchi, helping to move mucus and trapped particles toward the pharynx.
Hyaline cartilage
Provides structural support to the trachea and bronchi, preventing collapse during breathing.
Smooth muscle regulation
Found in the walls of the bronchi and bronchioles, controlling airway diameter
Airway constriction
Mediated by the parasympathetic nervous system via the vagus nerve, leading to bronchoconstriction.
Pseudostratified columnar epithelium
lines the upper airways, providing a protective barrier and mucociliary clearance.
Goblet cells (functional relationship)
Produce mucus, which traps inhaled particles and pathogens.
Mucus clearance
The cilia of the pseudostratified columnar epithelium transport mucus and trapped particles towards the pharynx.
Bronchodilation
Mediated by the sympathetic nervous system, allowing for increased airflow.
Asthma
Airway hyperresponsiveness, leading to bronchoconstriction, increased mucus production, and inflammation.
Involves smooth muscle contraction and thickening of the bronchial wall.
COPD
Chronic obstructive pulmonary disease (COPD)
Chronic bronchitis or Emphysema
Chronic bronchitis
excessive mucus production and inflammation of the bronchi
Emphysema
destruction of the alveolar walls, leading to loss of elastic recoil and air trapping.
Lung cancer
Can originate in the bronchial epithelium (bronchogenic carcinoma)
May obstruct airways or invade adjacent structures in the mediastinum.
Trachea
A flexible tube supported by C-shaped hyaline cartilage rings
Carina
A ridge at the bifurcation of the trachea, marking the division into the main bronchi
Main (primary) bronchi
The right main bronchus is wider, shorter, and more vertical than the left
The left main bronchus is narrower and more horizontal
Lobar (secondary) bronchi
The right lung has three lobar bronchi
The left lung has two lobar bronchi
Segmental (tertiary) bronchi
Each lobar bronchus divides into segmental bronchi which supply bronchopulmonary segments.
Bronchioles
Smaller airways that lack cartilage and are primary regulated by smooth muscle
Termnial bronchioles
The last branches of the conducting airways before the respiratory zone.
Alveolar ducts
thin-walled passages leading to the alveolar sacs.
Alveolar sacs
clusters of alveoli, where gas exchange occurs.
