Respiration and Gas Exchange

Mitral regurgitation causes volume overload of the left ventricle and left atrium. This leads to pulmonary venous hypertension, which increases pulmonary blood volume. The increased residual volume occurs because of the elevated pulmonary venous pressure and subsequent fluid shifts. This is a manifestation of pulmonary congestion secondary to left-sided valvular insufficiency.

Shock lung (ARDS) shows diffuse alveolar damage with hyaline membranes, alveolar edema, and inflammation. Diffuse alveolar edema is the hallmark histological finding. Hemosiderosis indicates iron overload, while interstitial pneumonia is a different pathological process.

In autopsy of asphyxial deaths, the neck is examined last to preserve ligature marks and contusions that could be disrupted during earlier dissection. This sequence ensures critical forensic evidence remains intact.

The findings (mediastinal shift to right, scaphoid abdomen, pulse impulse shifted right) in an intubated child indicate left-sided tension pneumothorax or massive gastric distension from air trapping. Placing a nasogastric tube to decompress the stomach is the immediate next step. Removing ETT is unsafe, surgery is premature, and chest tube is for pneumothorax (but rule out gastric issue first).

The pulmonary circulation is powered by the right atrium (which receives deoxygenated blood from the body) and the right ventricle (which pumps this blood to the lungs). The left atrium and ventricle handle systemic circulation. Both chambers work together to power pulmonary flow.

Lateral wall of the nasal cavity is mainly made up by the maxilla, however there is a deficiency that is compensated by: the perpendicular plate of the palatine bone, the medial pterygoid plate, the labyrinth of the ethmoid and the inferior concha. The nasal cavity is enclosed by the nasal bone.

Various steps in respiration are controlled by enzymes.

Spirometry is the standard pulmonary function test for measuring lung volumes. Vital capacity is specifically measured by having a patient inhale maximally and exhale forcefully into the spirometer, which records the volume expelled.

Pneumonia is an inflammatory condition of the lung primarily affecting the alveoli (air sacs). It can be caused by bacterial, viral, or fungal infections. The liver filters blood, the heart pumps blood, and the eyes are for vision - none of these are directly affected by pneumonia.

Alveoli are the tiny sacs within our lungs that allow oxygen and carbon dioxide to move between the lungs and the bloodstream.

R.Q. is the ratio of the volume of CO₂ released to the volume of O₂ absorbed during respiration.

Alveolus is the tiny air sac (only 1 cell thick) in the lungs at the end of the smallest airways, where the exchange of oxygen and carbon dioxide takes place. This is the functional unit of lungs.

The branches of trachea entering into the lungs are called bronchi. They are further branched into secondary and tertiary bronchi, which further branch in bronchioles.

The gaseous exchange in fishes takes through gills. Gills also known as branchiae, are small portions of richly vascularised tissues, internal or external to the body and in direct contact with the surrounding water.