Pleural effusion

Pleural effusion is excess fluid that accumulates in the pleural cavity, the fluid-filled space that surrounds the lungs. This excess can impair breathing by limiting the expansion of the lungs. Various kinds of pleural effusion, depending on the nature of the fluid and what caused its entry into the pleural space, are hydrothorax (serous fluid), hemothorax (blood), urinothorax (urine), chylothorax (chyle), or pyothorax (pus). Pneumothorax is the accumulation of air in the pleural space.

Types

Five types of fluids can accumulate in the pleural space:

On the basis of fluid present -

On the basis of associated infection-

Causes

Transudative

The most common causes of transudative pleural effusions in the United States are heart failure, and cirrhosis (causing hepatic hydrothorax). Nephrotic syndrome leading to increased loss of albumin and resultant low albumin and reduced colloid osmotic pressure is another, less common, cause. Pulmonary embolisms were once thought to be associated with transudative effusions but have been recently shown to be exudative. The mechanism for the transudative pleural effusion is probably related to increased permeability of the capillaries in the lung, which results from the release of cytokines or inflammatory mediators (e.g. vascular endothelial growth factor) from the platelet-rich blood clots. The excessive interstitial lung fluid traverses the visceral pleura and accumulates into the pleural space.

Khan Academy

Khan Academy is a non-profit educational organization created in 2006 by educator Salman Khan with the aim of providing a free, world-class education for anyone, anywhere. The organization produces short lectures in the form of YouTube videos. In addition to micro lectures, the organization's website features practice exercises and tools for educators. All resources are available for free to anyone around the world. The main language of the website is English, but the content is also available in other languages.

History

The founder of the organization, Salman Khan, was born in New Orleans, Louisiana, United States to immigrant parents from Bangladesh and India. After earning three degrees from the Massachusetts Institute of Technology (a BS in mathematics, a BS in electrical engineering and computer science, and an MEng in electrical engineering and computer science), he pursued an MBA from Harvard Business School.

In late 2004, Khan began tutoring his cousin Nadia who needed help with math using Yahoo!'s Doodle notepad.When other relatives and friends sought similar help, he decided that it would be more practical to distribute the tutorials on YouTube. The videos' popularity and the testimonials of appreciative students prompted Khan to quit his job in finance as a hedge fund analyst at Connective Capital Management in 2009, and focus on the tutorials (then released under the moniker "Khan Academy") full-time.

Pleural cavity

In human anatomy, the pleural cavity is the thin fluid-filled space between the two pulmonary pleurae (visceral and parietal) of each lung. A pleura is a serous membrane which folds back onto itself to form a two-layered membranous pleural sac. The outer pleura (parietal pleura) is attached to the chest wall, but is separated from it by the endothoracic fascia. The inner pleura (visceral pleura) covers the lungs and adjoining structures, including blood vessels, bronchi and nerves. The pleural cavity can be viewed as a potential space because the two pleurae adhere to each other (through the thin film of serous liquid) under all normal conditions.

Structure

In humans, there is no anatomical connection between the left and right pleural cavities. Therefore, in cases of pneumothorax, the other lung will still function normally unless there is a tension pneumothorax or simultaneous bilateral pneumothorax, which may collapse the contralateral parenchyma, blood vessels and bronchi.

Respiratory system

The respiratory system (called also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for the process of respiration in an organism. The respiratory system is involved in the intake and exchange of oxygen and carbon dioxide between an organism and the environment.

In air-breathing vertebrates like human beings, respiration takes place in the respiratory organs called lungs. The passage of air into the lungs to supply the body with oxygen is known as inhalation, and the passage of air out of the lungs to expel carbon dioxide is known as exhalation; this process is collectively called breathing or ventilation. In humans and other mammals, the anatomical features of the respiratory system include trachea, bronchi, bronchioles, lungs, and diaphragm. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process occurs in the alveoli (air sacs) in the lungs.

Academy

An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary education or higher learning, research, or honorary membership. The name traces back to Plato's school of philosophy, founded approximately 385 BC at Akademia, a sanctuary of Athena, the goddess of wisdom and skill, north of Athens, Greece.

The original Academy

Before Akademia was a school, and even before Cimon enclosed its precincts with a wall, it contained a sacred grove of olive trees dedicated to Athena, the goddess of wisdom, outside the city walls of ancient Athens. The archaic name for the site was Hekademia, which by classical times evolved into Akademia and was explained, at least as early as the beginning of the 6th century BC, by linking it to an Athenian hero, a legendary "Akademos". The site of Akademia was sacred to Athena and other immortals.

Plato's immediate successors as "scholarch" of Akademia were Speusippus (347–339 BC), Xenocrates (339–314 BC), Polemon (314–269 BC), Crates (ca. 269–266 BC), and Arcesilaus (ca. 266–240 BC). Later scholarchs include Lacydes of Cyrene, Carneades, Clitomachus, and Philo of Larissa ("the last undisputed head of the Academy"). Other notable members of Akademia include Aristotle, Heraclides Ponticus, Eudoxus of Cnidus, Philip of Opus, Crantor, and Antiochus of Ascalon.