sodium

Examples of sodium in the following topics:

• Sodium Balance Regulation

  • The body has potent sodium retaining mechanisms and even if a person is on five mmol Na+/day they can maintain sodium balance.
  • Sodium is lost through the kidneys, sweat, and feces.
  • In states of sodium excess aldosterone levels decrease.
  • When aldosterone has been activated to retain sodium the plasma sodium tends to rise.
  • In states of sodium depletion, aldosterone levels increase, and in states of sodium excess, aldosterone levels decrease.

• Electrolysis of Sodium Chloride

  • Two commonly used methods of electrolysis involve molten sodium chloride and aqueous sodium chloride, which give different products.
  • Two commonly used methods of electrolysis involve molten sodium chloride and aqueous sodium chloride.
  • Sodium ions migrate to the cathode, where electrons enter the melt and are reduced to sodium metal:
  • What happens when we have an aqueous solution of sodium chloride?
  • Rather than producing sodium, hydrogen is produced.

• Primary Active Transport

  • The sodium-potassium pump maintains the electrochemical gradient of living cells by moving sodium in and potassium out of the cell.
  • Three sodium ions bind to the protein.
  • The protein's affinity for sodium decreases, and the three sodium ions leave the carrier.
  • The protein now has a higher affinity for sodium ions, and the process starts again.
  • For every three ions of sodium that move out, two ions of potassium move in.

• Nucleophilic Addition Reactions & Reduction

  • To understand how this reduction occurs we first need to identify two distinct reactions of sodium with liquid ammonia (boiling point -78 ºC).
  • In the first, sodium dissolves in the pure liquid to give a deep blue solution consisting of very mobile and loosely bound electrons together with solvated sodium cations (first equation below).
  • In the second case, ferric salts catalyze the reaction of sodium with ammonia, liberating hydrogen and forming the colorless salt sodium amide (second equation).
  • This is analogous to the reaction of sodium with water to give sodium hydroxide, but since ammonia is 1018 times weaker an acid than water, the reaction is less violent.
  • The usefulness of this reaction is that sodium amide, NaNH2, is an exceedingly strong base (18 powers of ten stronger than sodium hydroxide), which may be used to convert very weak acids into their conjugate bases.

• The Action Potential and Propagation

  • The depolarization, also called the rising phase, is caused when positively charged sodium ions (Na+) suddenly rush through open voltage gated sodium channels into a neuron.
  • As additional sodium rushes in, the membrane potential actually reverses its polarity.  
  • As a result, the membrane permeability to sodium declines to resting levels.
  • The hyper polarization is a phase where some potassium channels remain open, and sodium channels reset.
  • The period from the opening of the sodium channels until the sodium channels begin to reset is called the absolute refractory period.

• Salts that Produce Basic Solutions

  • An example of a basic salt is sodium bicarbonate, NaHCO3.
  • Because it is capable of deprotonating water and yielding a basic solution, sodium bicarbonate is a basic salt.
  • Sodium chloride, for instance, contains chloride (Cl-), which is the conjugate base of HCl.
  • Because the bicarbonate ion is the conjugate base of carbonic acid, a weak acid, sodium bicarbonate will yield a basic solution in water.

• Other Hormonal Controls for Osmoregulation

  • This, in turn, stimulates the renal tubules to reabsorb more sodium.
  • One type of mineralocorticoid, known as aldosterone, regulates sodium levels in the blood.
  • Almost all of the sodium in the blood is reclaimed by the renal tubules under the influence of aldosterone.
  • As sodium is always reabsorbed by active transport and water follows sodium to maintain osmotic balance, aldosterone manages not only sodium levels, but also the water levels in body fluids.
  • Aldosterone also stimulates potassium secretion concurrently with sodium reabsorption.

• Ions and Ionic Bonds

  • As illustrated, sodium (Na) only has one electron in its outer electron shell.
  • When sodium loses an electron, it will have 11 protons, 11 neutrons, and only 10 electrons.
  • It is now referred to as a sodium ion.
  • For instance, positively charged sodium ions and negatively charged chloride ions bond together to form sodium chloride, or table salt, a crystalline molecule with zero net charge.
  • Certain salts are referred to in physiology as electrolytes (including sodium, potassium, and calcium).

• Sodium Pumps as an Alternative to Proton Pumps

  • Na+/K+-ATPase (Sodium-potassium adenosine triphosphatase, also known as Na+/K+ pump, sodium-potassium pump, or sodium pump) is an antiporter enzyme (EC 3.6.3.9) (an electrogenic transmembrane ATPase) located in the plasma membrane of all animal cells.
  • Active transport is responsible for cells containing relatively high concentrations of potassium ions but low concentrations of sodium ions.
  • The sodium-potassium pump was discovered in the 1950s by Danish scientist Jens Christian Skou.
  • Second, because Na+ concentrations in most natural environments are almost 106-fold higher than H+ concentrations, sodium motive force levels are unlikely to change as rapidly as proton motive force levels, making sodium motive force a much more reliable source of energy.
  • Describe the mechanisms of sodium pumps and its role as an alternative proton pump

• Reactants and Reagents

  • Thus, reaction of 1-bromopropane with sodium cyanide proceeds smoothly to yield butanenitrile, whereas 1-bromo-2,2-dimethylpropane fails to give any product and is recovered unchanged.
  • For example, 2-bromopropane gives a substitution reaction with sodium methylthiolate but undergoes predominant elimination on treatment with sodium methoxide.