surfactant

Examples of surfactant in the following topics:

• Factors Affecting Pulmonary Ventilation: Surface Tension of Alveolar Fluid

  • The surface tension of alveolar fluid is regulated by pulmonary surfactant, allowing efficient respiration.
  • They lack sufficient surfactant to initiate proper breathing, and therefore, go into respiratory distress.
  • Fortunately, the type II epithelial cells of the alveoli continually secrete a molecule called surfactant that solves this problem.
  • Surfactant is a lipoprotein molecule that reduces the force of surface tension from water molecules on the lung tissue.
  • It is treated through pulmonary surfactant replacement therapy and mechanical ventilator treatment until the infant's lungs are old enough to secrete enough surfactant to survive on their own.

• The Work of Breathing

  • Breathing includes several components, including flow-resistive and elastic work; surfactant production; and lung resistance and compliance.
  • Surfactant is a complex mixture of phospholipids and lipoproteins that works to reduce the surface tension that exists between the alveoli tissue and the air found within the alveoli.
  • Surfactant works like a detergent to reduce the surface tension, allowing for easier inflation of the airways.
  • Sometimes, in babies that are born prematurely, there is lack of surfactant production; as a result, they suffer from respiratory distress syndrome and require more effort to inflate the lungs.
  • Explain the roles played by surfactant, flow-resistive and elastic work, and lung resistance and compliance in breathing

• Hydrophilic and Hydrophobic Colloids

  • One important class of emulsifiers is known as "surface active substances," or surfactants.
  • Soy and egg yolk lecithin are examples of surfactants.
  • Surfactants are often used in food, such as mayonnaise and salad dressing, to keep the emulsions mixed over time.
  • Detergents are another class of surfactants, and they will physically interact with both oil and water, thus stabilizing the interface between the oil and water droplets in suspension.

• Development of the Respiratory System

  • Specialized cells of the respiratory epithelium appear including type II alveolar cells which secrete pulmonary surfactant.
  • This surfactant is important in reducing the surface tension at the air-alveolar surface, allowing expansion of the terminal saccules.
  • Pre-term birth can lead to infants with under-developed alveolar type II cells which produce surfactant.
  • The lungs of pre-term infants therefore may not function well because the lack of surfactant leads to increased surface tension within the alveoli leading to alveoli collapse and no gas exchange, a condition known as respiratory distress syndrome.

• Alveoli

  • Type II (Great Alveolar) cells: These are the site of surfactant production in the lungs, making them critical for maintaining the elastic recoil of the lung.
  • The surfactant produced by type II epithelial cells is very important for maintaining the elastic recoil of the lungs.
  • Without surfactant, the surface tension would cause the lungs to collapse during exhalation, making normal breathing impossible.
  • Surfactant is first produced by human lungs between 24 and 28 weeks in the womb, and many infants born prematurely do not have enough surfactant to breathe on their own after birth.
  • Surfactant replacement therapy is necessary to save the lives of these premature births.

• Soaps & Detergents

  • Substances that accumulate at water surfaces and change the surface properties are called surfactants.
  • Alkali metal salts of fatty acids are more soluble in water than the acids themselves, and the amphiphilic character of these substances also make them strong surfactants.
  • The use of such compounds as cleaning agents is facilitated by their surfactant character, which lowers the surface tension of water, allowing it to penetrate and wet a variety of materials.
  • Very small amounts of these surfactants dissolve in water to give a random dispersion of solute molecules.
  • The surfactant molecules reversibly assemble into polymolecular aggregates called micelles.

• Factors that Affect Germicidal Activity of Chemicals

  • They are commonly referred to as "surgical alcohol. " They are used to disinfect the skin before injections are given, often along with iodine (tincture of iodine) or some cationic surfactants (benzalkonium chloride 0.05–0.5%, chlorhexidine 0.2–4.0%, or octenidine dihydrochloride 0.1–2.0%).
  • The antimicrobial activity of Quats is inactivated by anionic surfactants, such as soaps.
  • It is a cationic surfactant, similar to Quats.
  • Octenidine dihydrochloride: A cationic surfactant and bis-(dihydropyridinyl)-decane derivative, used in concentrations of 0.1–2.0%.

• Bile

  • Bile acts as a surfactant, helping to emulsify the fats in the food, in the same way in which soap emulsifies fat.

• Expiration

  • The elasticity of the lungs is due to molecules called elastins in the extracellular matrix of lung tissues and is maintained by surfactant, a chemical that prevents the elasticity of the lungs from becoming too great by reducing surface tension from water.
  • Without surfactant the lungs would collapse at the end of expiration, making it much more difficult to inhale again.

• Adjustments of the Infant at Birth

  • Following birth, the expression and re-uptake of surfactant, which begins production at 20 weeks gestation, is accelerated.
  • Expression of surfactant into the alveoli is necessary to prevent alveolar closure.