The anterior mediastinum contains:
Loose connective tissue (the sternopericardial ligaments that help secure the position of the heart in the thoracic cavity - fibrous bands that link the pericardium to the sternum)
Fat
Lymphatic vessels
Lymph nodes

It is a physiological condition whereby the bases of the lungs receive more oxygen and blood flow than the apex of the lungs (however, the overall driver of this mismatch is the difference in perfusion). The apex of the lung has a greater VQ than the base

Asthma is a chronic inflammatory disease of the airways. It is characterized by an exaggerated contractile response of the airways to a variety of stimuli, which leads to airflow limitation, manifesting in the clinical symptoms of intermittent dyspnea, co

Stridor – high-pitched musical breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree

Wheeze – continuous, coarse, whistling sound produced in the respiratory airways during breathing
– Narrowed or obstructed airway

Type 1 pneumocytes, 40% of the alveolar cell population that allow gaseous diffusion (90% of surface area), type 2 pneumocytes, 60% of the alveolar cell population, which secrete surfactant, and alveolar macrophages that lie on top of alveolar lining cell

Pulsus paradoxus is present in patients with cardiac tamponade (fluid accumulation in the pericardium), and in patients with obstructive lung disorders.

Allergic –
Caused by airway hyper-responsiveness to allergens, such as pollens, mold, dust mites and animal dander
Non-Allergic –
Caused by airway hyper-responsiveness to things other than allergens, such as cigarette smoke and viral infections.

These changes include: bronchial smooth muscle hypertrophy and hyperplasia, epithelial injury, increase airway vascularity, increased mucus gland hypertrophy and hyperplasia, and subepithelial deposits of collagen.

Inhale: the diaphragm and external intercostals muscles contract, the intrapleural pressure becomes more negative, the alveolar pressure falls below atmospheric pressure. Exhale: the diaphragm relaxes, intrapleural pressure becomes less negative and alveo

o Increased airway resistance causes an overstated change in the stroke volume
o Hyperventilation of the chest will cause a larger decrease in intrathoracic pressure

Mainly patient education including guidance on the avoidance of tobacco smoke, and the relationship between increased BMI and severity of asthma.

Bronchoconstriction is the dominating characteristic of the early phase, along with increased mucus production and variable vasodilation with increase vascular permeability. Bronchoconstriction is caused by direct vagal stimulation.

The late phase consi

Obstructive: (decreased ability to empty lungs): Total Lung Capacity relatively normal; Functional Residual Capacity and Residual Volume increased, while Volume Capacity is decreased; mainly has problem with expiration. Examples: asthma and COPD. Restrict

In asthma the VQ mismatch is exacerbated - the overall VQ of the lung becomes lower, indicating that there has been a decrease in ventilation.In the case of pulmonary embolism the overall VQ ratio of the lung actually increases, as there is a decrease in

Relievers and preventers. Relievers: beta-adrenoceptor agonists, leukotrienes antagonists, anticholinergic drugs, and xanthines. Preventers: cromoglycate, nedocromil, and glucocorticoids.

Hypoxemic respiratory failure (type I) is characterized by an arterial PaO2 lower than 60 mmHg with a normal or low arterial PaCO2 (less functioning lung tissue is required for carbon dioxide excretion) and increased PA-aO2; typically caused by V/Q mismat

See Notes

Hyperventilation results in hypocapnoea (a reduction of CO2 within the blood), because the more we breathe the more gas exchange effectively occurs at the border of the capillaries and the alveoli. Carbon dioxide has a high diffusion coefficient so it eff

If left untreated, long-term effects of asthma include airway remodeling: Increased sizes of the layers, subepithelial fibrosis, increase in smooth muscle mass, mucus hyper secretion. This is all irreversible, leading to permanent decrease in lung functio

1) Leukotrienes C4, D4, and E4 cause prolonged bronchoconstriction as well as increased vascular permeability and increased mucus secretion.
2) Acetylcholine causes airway smooth muscle constriction by directly stimulating muscarinic receptors.
3) Histam