tension

Examples of tension in the following topics:

• Partition and Religious Tensions

• Tensions in the South China Sea

• Control of Muscle Tension

  • Muscle tension is influenced by the number of cross-bridges that can be formed.
  • The pull exerted by a muscle is called tension.
  • If more cross-bridges are formed, more myosin will pull on actin and more tension will be produced.
  • This results in fewer myosin heads pulling on actin and less muscle tension.
  • Muscle tone is residual muscle tension that resists passive stretching during the resting phase.

• Surface Tension

  • Surface tension is responsible for the shape of a liquid droplet.
  • Different liquids and solutions have different surface tensions.
  • The surface tensions of a few common liquids and solutions are as follows, in dyne/cm (note the particularly high surface tension of water):
  • Water striders can "walk" on water as a result surface tension.
  • Note that the forces from the surface tension are symmetrical.

• Surface Tension and Capillary Action

  • Attractive forces between molecules cause effects such as surface tension and capillary action.
  • Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
  • The cohesive forces among liquid molecules are responsible for the phenomenon of surface tension, as shown in .
  • Surface tension has the unit of force per unit length, or of energy per unit area.
  • If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and the container act to lift the liquid.

• Factors Affecting Pulmonary Ventilation: Surface Tension of Alveolar Fluid

  • The surface tension of alveolar fluid is regulated by pulmonary surfactant, allowing efficient respiration.
  • As the air inside the lungs is moist, there is considerable surface tension within the tissue of the lungs.
  • Because the alveoli of the lungs are highly elastic, they do not resist surface tension on their own, which allows the force of that surface tension to deflate the alveoli as air is forced out during exhalation by the contraction of the pleural cavity.
  • The force of surface tension in the lungs is so great that without something to reduce the surface tension, the airways would collapse after exhalation, making re-inflation during inhalation much more difficult and less effective.
  • The net result is that the surface tension of the lungs from water is reduced so that the lungs can still inflate and deflate properly without the possibility of collapse from surface tension alone.

• Connected Objects

  • One can think of the force transferring through the connection by means of the "tension" force.
  • Tension is the pulling force exerted by a string, chain, or similar connector on another object.
  • If two objects are connected by a string, a force exerted on one is balanced by a tension force in the string which pulls on the other.
  • Of course, if the tension force is greater than the rope can withstand, the rope will break.
  • Tension is the force of the rope on the scaffold, the force of the rope on the ball, and the balanced forces acting on and produced by segments of the rope.

• Hypotonia and Hypertonia

  • Hypertonia is the reduced ability of muscles to stretch due to increased muscle tension; hypotonia, due to chronic reduced muscle tension.
  • Hypertonia is a reduction in the ability of a muscle to stretch due to increased muscle tension; it is caused by lesions to upper motor neurons.
  • Hypotonia is the state of reduced muscle tone and tension, resulting in lessened ability to generate force from muscle contractions.

• Surface Tension

  • Surface tension is the tendency of a liquid surface to resist forces applied to it.
  • Also, a paper clip or pin can be supported by the surface tension at a water air interface .
  • Therefore, the surface tension will be a property of the interface rather than simply the liquid.
  • In both cases, the vertical component of the surface tension is enough to support the weight of the object.
  • Summarize the cause for different surface tensions at a liquid's surface

• Confederate Politics

  • Confederate politics were dominated by the tension between states' rights and the military needs of the Confederacy.
  • States' rights, one of the primary platforms for secession, was an enduring issue in Confederate politics that caused tension between state leaders and President Jefferson Davis.
  • Examine the tensions between Confederate state leaders and President Jefferson Davis.