electrogenic pump

Examples of electrogenic pump in the following topics:

• Primary Active Transport

  • The sodium-potassium pump maintains the electrochemical gradient of living cells by moving sodium in and potassium out of the cell.
  • One of the most important pumps in animals cells is the sodium-potassium pump (Na+-K+ ATPase), which maintains the electrochemical gradient (and the correct concentrations of Na+ and K+) in living cells.
  • The sodium-potassium pump moves two K+ into the cell while moving three Na+ out of the cell.
  • The sodium-potassium pump is, therefore, an electrogenic pump (a pump that creates a charge imbalance), creating an electrical imbalance across the membrane and contributing to the membrane potential.
  • Primary active transport moves ions across a membrane, creating an electrochemical gradient (electrogenic transport).

• Structures of the Heart

  • The heart pumps blood through the body with the help of structures such as ventricles, atria, and valves.
  • For pulmonary and systemic circulation, the heart has to pump blood to the lungs or the rest of the body, respectively .
  • The atria are the chambers that receive blood while the ventricles are the chambers that pump blood.
  • After it is filled, the right ventricle pumps the blood through the pulmonary arteries to the lungs for re-oxygenation.
  • This pattern of pumping is referred to as double circulation and is found in all mammals.

• ATP: Adenosine Triphosphate

  • For example, transmembrane ion pumps in nerve cells use the energy from ATP to pump ions across the cell membrane and generate an action potential.
  • The sodium-potassium pump (Na+/K+ pump) drives sodium out of the cell and potassium into the cell .
  • When ATP is hydrolyzed, it transfers its gamma phosphate to the pump protein in a process called phosphorylation.
  • By donating free energy to the Na+/K+ pump, phosphorylation drives the endergonic reaction.
  • Sodium-potassium pumps use the energy derived from exergonic ATP hydrolysis to pump sodium and potassium ions across the cell membrane.

• Open and Closed Circulatory Systems

  • The circulatory system is effectively a network of cylindrical vessels (the arteries, veins, and capillaries) that emanate from a pump (the heart).
  • In an open circulatory system, the blood is not enclosed in the blood vessels, but is pumped into a cavity called a hemocoel.
  • (a) In closed circulatory systems, the heart pumps blood through vessels that are separate from the interstitial fluid of the body.
  • (b) In open circulatory systems, a fluid called hemolymph is pumped through a blood vessel that empties into the body cavity.

• Blood Flow Through the Body

  • The heart pumps oxygenated and deoxygenated blood throughout the body in a complex system of arteries, veins, and capillaries.
  • As the heart pumps, blood is pushed through the body through the entire circulatory system .
  • Oxygenated blood is pumped away from the heart to the rest of the body, while deoxygenated blood is pumped to the lungs where it is reoxygenated before returning to the heart.
  • With each rhythmic pump of the heart, blood is pushed under high pressure and velocity away from the heart, initially along the main artery, the aorta .

• Electron Transport Chain

  • Complex I can pump four hydrogen ions across the membrane from the matrix into the intermembrane space; it is in this way that the hydrogen ion gradient is established and maintained between the two compartments separated by the inner mitochondrial membrane.
  • Since these electrons bypass, and thus do not energize, the proton pump in the first complex, fewer ATP molecules are made from the FADH2 electrons.
  • The number of ATP molecules ultimately obtained is directly proportional to the number of protons pumped across the inner mitochondrial membrane.
  • Complex III pumps protons through the membrane and passes its electrons to cytochrome c for transport to the fourth complex of proteins and enzymes.
  • In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.

• The Cardiac Cycle

  • The main purpose of the heart is to pump blood through the body; it does so in a repeating sequence called the cardiac cycle.
  • In each cardiac cycle, the heart contracts (systole), pushing out the blood and pumping it through the body.
  • The pumping of the heart is a function of the cardiac muscle cells, or cardiomyocytes, that comprise the heart muscle.
  • Cardiomyocytes are distinctive muscle cells that are striated like skeletal muscle, but pump rhythmically and involuntarily like smooth muscle; they are connected by intercalated disks exclusive to cardiac muscle .
  • This pause allows the blood in the atria to empty completely into the ventricles before the ventricles pump out the blood.

• Transport of Electrolytes across Cell Membranes

  • Active transport requires energy in the form of ATP conversion, carrier proteins, or pumps in order to move ions against the concentration gradient.
  • Specific examples, such as GLUT and the Na/K, pump are included.

• The Role of the Circulatory System

  • Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself.
  • The heart is central to the human circulatory system, as it pumps blood throughout the body.

• Malpighian Tubules of Insects

  • Metabolic wastes, such as urea and amino acids, freely diffuse into the tubules, while ions are transported through active pump mechanisms.
  • There are exchange pumps lining the tubules which actively transport H+ ions into the cell and K+ or Na+ ions out; water passively follows to form urine.