cephalic phase

Examples of cephalic phase in the following topics:

• Cephalic Phase

  • The cephalic phase of gastric secretion occurs even before food enters the stomach via neurological signals.
  • The cephalic phase of gastric secretion occurs even before food enters the stomach, especially while it is being eaten.
  • Neurogenic signals that initiate the cephalic phase of gastric secretion originate from the cerebral cortex, and in the appetite centers of the amygdala and hypothalamus.
  • When appetite is depressed this part of the cephalic reflex is inhibited.
  • Cephalic phase causes ECL cells to secrete histamine and increase HCl acid in the stomach.

• Neural Responses to Food

  • All three phases of digestive responses to food (the cephalic, gastric, and intestinal stages) are managed through enzymatic neural control.
  • There are three overlapping phases of gastric control: the cephalic phase, the gastric phase, and the intestinal phase.
  • The first phase of ingestion, called the cephalic phase, is controlled by the neural response to the stimulus provided by food.
  • The gastric and salivary secretion in the cephalic phase can also take place at the thought of food.
  • It builds on the stimulation provided during the cephalic phase.

• Veins of the Upper Limbs

  • The major superficial veins of the upper limb are the cephalic, median cubital and basilic veins.
  • The cephalic vein arises from the dorsal venous network of the hand and passes the elbow anteriorly, continuing up the upper arm to the shoulder.
  • The basilic vein follows a similar path but is located medially to the cephalic vein.
  • At the elbow, the basilic and cephalic veins are linked by the median cubital vein, from which blood is often drawn.

• Anencephaly

  • Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th day of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp.
  • Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close.

• Interpreting Phase Diagrams

  • The lines that separate these single phase regions are known as phase boundaries.
  • By focusing attention on distinct single phase regions, phase diagrams help us to understand the range over which a particular pure sample of matter exists as a particular phase.
  • When evaluating the phase diagram, it is worth noting that the solid-liquid phase boundary in the phase diagram of most substances has a positive slope.
  • With a knowledge of the major components of phase diagrams and the features of phase plots, a phase diagram can be used to understand how altering thermodynamic parameters influences the states/phases of matter a sample of a substance is in.
  • A typical phase diagram illustrating the major components of a phase diagram as well as the critical point.

• Major Features of a Phase Diagram

  • A phase diagram is a graph which shows under what conditions of temperature and pressure distinct phases of matter occur.
  • The simplest phase diagrams are of pure substances.
  • The major features of a phase diagram are phase boundaries and the triple point.
  • Phase boundaries, or lines of equilibrium, are boundaries that indicate the conditions under which two phases of matter can coexist at equilibrium.
  • In this phase diagram, which is typical of most substances, the solid lines represent the phase boundaries.

• Solid to Gas Phase Transition

  • Sublimation is the phase transition from the solid to the gaseous phase, without passing through an intermediate liquid phase.
  • Sublimation is the process of transformation directly from the solid phase to the gaseous phase, without passing through an intermediate liquid phase.
  • It is an endothermic phase transition that occurs at temperatures and pressures below a substance's triple point (the temperature and pressure at which all three phases coexist) in its phase diagram.
  • But at temperatures below that of the triple point, a decrease in pressure will result in a phase transition directly from the solid to the gaseous.
  • At temperatures and pressures below those of the triple point, a phase change between the solid and gas phases can take place.

• Superphylum Lophotrochozoa

  • They also show the beginning of cephalization: the evolution of a concentration of nervous tissues and sensory organs in the head of the organism, which is where it first encounters its environment.

• Phase-Contrast Microscopy

  • In phase-contrast microscopy, parallel beams of light are passed through objects of different densities.
  • A phase ring in condenser allows a cylinder of light to pass through it while still in phase.
  • Unaltered light hits the phase ring in the lens and is excluded.
  • Phase-contrast images have a characteristic grey background with light and dark features found across the sample.
  • One disadvantage of phase-contrast microscopy is halo formation called halo-light ring.

• The Evaporating Atmosphere

  • Within each phase, the properties are uniform but between the two phases properties differ.
  • Water in a closed jar with an air space over it forms a two phase system.
  • Even at equilibrium, molecules are constantly in motion and, once in a while, a molecule in the liquid phase gains enough kinetic energy to break away from the liquid phase and enter the gas phase.
  • The water vapor in it changes phases.
  • It is in a phase equilibrium.