odorant

Examples of odorant in the following topics:

• Olfaction: The Nasal Cavity and Smell

  • The olfactory system gives humans their sense of smell by inhaling and detecting odorants in the environment.
  • Each of the 350 receptor types is characteristic of only one odorant type.
  • These proteins carry out the transduction of odorants into electrical signals for neural processing.
  • Individual features of odor molecules descend on various parts of the olfactory system in the brain and combine to form a representation of odor.
  • Humans can differentiate between 10,000 different odors.

• Tastes and Odors

  • Both taste and odor stimuli are molecules taken in from the environment.
  • All odors that we perceive are molecules in the air we breathe.
  • Humans have about 350 olfactory receptor subtypes that work in various combinations to allow us to sense about 10,000 different odors.
  • Compare that to mice, for example, which have about 1,300 olfactory receptor types and, therefore, probably sense many more odors.

• Taste and Smell at Birth and in Old Age

  • At birth, infants can show different expressions of disgust or pleasure when presented with pleasant odors (honey, milk, etc.) or unpleasant odors (rotten egg) and tastes (e.g. sour taste).
  • Infants are responsive to the olfactory cues associated with maternal breast odors.
  • Maternal breast odors signal the presence of a food source for the newborn.
  • These breast odors bring forth positive responses in neonates from as young as one hour or less through several weeks postpartum.
  • Anosmia, a lack of functioning olfaction (inability to perceive odors), may be temporary, but traumatic anosmia can be permanent.

• Reception and Transduction

  • Odorants (odor molecules) enter the nose and dissolve in the olfactory epithelium, the mucosa at the back of the nasal cavity .
  • Humans have about 12 million olfactory receptors distributed among hundreds of different receptor types that respond to different odors.
  • It is the variations in their amino acid chains that make the receptors sensitive to different odorants.
  • The receptors are specialized to detect specific odorants, so the bipolar neurons themselves are specialized.
  • When an odorant binds with a receptor that recognizes it, the sensory neuron associated with the receptor is stimulated.

• Physical Characteristics of Urine

  • Physical characteristics that can be applied to urine include color, turbidity (transparency), smell (odor), pH (acidity - alkalinity) and density.
  • For example, urine of diabetics may have a sweet or fruity odor due to the presence of ketones (organic molecules of a particular structure) or glucose.
  • Generally fresh urine has a mild smell but aged urine has a stronger odor similar to that of ammonia.

• Sensory Absolute Thresholds

  • A classic example of absolute threshold is an odor test, in which a fragrance is released into an environment.
  • The absolute threshold in that scenario would be the least amount of fragrance necessary for a subject to detect that there is an odor.
  • If you've ever entered a room that has a terrible odor, but after a few minutes realized that you barely noticed it anymore, then you have experienced sensory adaptation.

• Properties of Sulfur

  • Octasulfur is a soft, bright-yellow solid with only a faint odor, similar to that of matches.
  • Sulfur burns with a blue flame, concomitant with formation of sulfur dioxide, notable for its peculiar suffocating odor.

• Overview of Gram-Positive Bacteria and Actinobacteria

  • Some types of Actinobacteria are responsible for the peculiar odor emanating from the soil after rain (petrichor), mainly in warmer climates.
  • The chemical that produces this odor is known as Geosmin.

• Bacterial Vaginosis

  • The most common symptom is white or gray discharge, that can be thin, with fish-like odor (especially strong after intercourse).
  • the release of fishy odor after the addition of 10% KOH to the specimen

• Overview of the Cerebrum

  • Its potential functions can be placed into four non-exclusive categories: discriminating among odors, enhancing sensitivity of odor detection, filtering out many background odors, and permitting higher brain areas involved in arousal and attention to modify the detection or the discrimination of odors.