saltatory conduction

Examples of saltatory conduction in the following topics:

• Nerve Impulse Transmission within a Neuron: Action Potential

  • The speed of conduction of an action potential along an axon is influenced by both the diameter of the axon and the axon's resistance to current leak.
  • Myelin acts as an insulator that prevents current from leaving the axon, increasing the speed of action potential conduction.
  • Diseases like multiple sclerosis cause degeneration of the myelin, which slows action potential conduction because axon areas are no longer insulated so the current leaks.
  • Action potential "jumps" from one node to the next in saltatory conduction.
  • The action potential is conducted down the axon as the axon membrane depolarizes, then repolarizes.

• Vascular Tissue: Xylem and Phloem

  • The simplest arrangement of conductive cells shows a pattern of xylem at the center surrounded by phloem.
  • The tissue consists of vessel elements, conducting cells, known as tracheids, and supportive filler tissue, called parenchyma .
  • Despite the fact that their cytoplasm is actively involved in the conduction of food materials, sieve-tube members do not have nuclei at maturity.
  • Tracheids (top) and vessel elements (bottom) are the water conducting cells of xylem tissue.

• Plant Tissues and Organ Systems

  • It is made of two specialized conducting tissues: xylem and phloem.
  • It includes three different cell types: vessel elements and tracheids (both of which conduct water) and xylem parenchyma.
  • Phloem tissue, which transports organic compounds from the site of photosynthesis to other parts of the plant, consists of four different cell types: sieve cells (which conduct photosynthates), companion cells, phloem parenchyma, and phloem fibers.
  • Unlike xylem-conducting cells, phloem-conducting cells are alive at maturity.

• Bryophytes

  • They generally lack lignin and do not have actual tracheids (xylem cells specialized for water conduction).
  • Rather, water and nutrients circulate inside specialized conducting cells.

• The Evolution of Plastids

  • Plastids may derive from cyanobacteria engulfed via endosymbiosis by early eukaryotes, giving cells the ability to conduct photosynthesis.
  • Chloroplasts are plastids that conduct photosynthesis.

• Homeostasis: Thermoregulation

  • Heat can be exchanged between an animal and its environment through four mechanisms: radiation, evaporation, convection, and conduction.
  • Heat can be conducted from one surface to another during direct contact with the surfaces, such as an animal resting on a warm rock.
  • Heat can be exchanged by four mechanisms: (a) radiation, (b) evaporation, (c) convection, or (d) conduction.

• Protists as Primary Producers, Food Sources, and Symbionts

  • (On land, terrestrial plants serve as primary producers. ) In fact, approximately one-quarter of the world's photosynthesis is conducted by protists, particularly dinoflagellates, diatoms, and multicellular algae.

• The Major Divisions of Land Plants

  • In contrast, vascular plants developed a network of cells, called xylem and phloem, that conduct water and solutes throughout the plant.

• Publishing Scientific Work

  • Collaboration with other scientists—when planning, conducting, and analyzing results—are all important for scientific research.
  • It is indispensable to conduct an extensive literature search to put the results in the context of previously-published scientific research.

• The Periodic Table

  • They have low electrical conductivity that increases with temperature.
  • Within the p-block at the boundary between the metallic elements (grey elements) and nonmetal elements (green elements) there is positioned boron and silicon that are metalloid in character (pink elements), i.e., they have low electrical conductivity that increases with temperature.