The Special Sense Organs and Their Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
The sense of smell is termed olfaction, osmesis, or osphresis. The olfactory receptor cells (neurons) are located high in the roof of the nasal cavity in the olfactory epithelium consisting of receptor cells, sustentacular or supporting cells, and basal cells. These neurons end in a bulbous olfactory vesicle or sac from which extend cilia that project through the fluid covering the surface epithelium. The olfactory bulbs connect olfactory nerve fibers to axons of neurons projecting into the olfactory area of the brain (Figure 13.1).
Frailty, Nutrition, and the Elderly
David Heber, Zhaoping Li in Primary Care Nutrition, 2017
The sense of smell is mediated through stimulation of the olfactory receptor cells by volatile chemicals. To stimulate the olfactory receptors, airborne molecules must pass through the nasal cavity with relatively turbulent air currents and contact the receptors. Odorants can also be perceived by entering the nose posteriorly through the nasopharynx to reach the olfactory receptor via retronasal olfaction. Each olfactory receptor cell is a primary sensory bipolar neuron. The average nasal cavity contains more than 100 million such neurons. There are more than 900 genes encoding these receptors. The olfactory neurons are unique because they are generated throughout life by the underlying basal cells. New receptor cells are generated approximately every 30–60 days.
The Sacred Sense
Kerry Hughes in The Incense Bible, 2014
Each time we inhale, we also smell. Our noses are equipped with small, dime-sized patches of olfactory membranes that supply the nerve endings to signal to our brains the sense of smell. We have hundreds of millions of these olfactory nerve cells, and each one has about six to twelve hairs, or cilia, with receptors. These nerve cells are each replaced every twenty-eight days. Every odor molecule fits into a specific receptor cell. As the receptors are stimulated by odors that are brought in by our inhalations, the nerve cells fire and send signals to the brain. The area of the brain that then processes the sense of smell is the oldest part of the brain, the limbic lobe, which is associated with our deepest desires and impulses, sexual and emotional impulses, including fear, joy, anxiety, depression, and anger. The limbic system also has direct control of the heart rate, blood pressure, breathing, stress levels, hormone balance, and memory (Williams, 2004; Aftel, 2001).
Is COVID-19 associated with self-reported audio-vestibular symptoms?
Published in International Journal of Audiology, 2022
Arwa AlJasser, Walid Alkeridy, Kevin J. Munro, Christopher J. Plack
The main section was designed with a five-point Likert scale to assess any self-reported change over time in nine symptoms under four categories.Olfactory and gustatory abnormalities which included disturbances in sense of smell and taste.Auditory symptoms which included hearing abilities (changes assessed for four variables: sense of hearing, ease of conversing by telephone, ability to follow a conversation with background noise, and preferred volume while listening to various media); non-pulsatile tinnitus; and hyperacusis (i.e. stress, irritation or sensitivity caused by noise and environmental sounds).Dizziness which included rotatory vertigo (the feeling that the person, or things around person, are spinning or moving); and stability (unsteadiness/light-headedness, losing balance or feeling unsteady when walking, climbing stairs, or picking something up off the floor).Ear symptoms which included ear pressure; and otalgia (ear pain).
Olfactory dysfunction in chronic rhinosinusitis: insights into the underlying mechanisms and treatments
Published in Expert Review of Clinical Immunology, 2023
Jing Song, Ming Wang, Chengshuo Wang, Luo Zhang
The existing clinical olfactory diagnostic methods, while informative, fall short in providing a truly objective assessment of olfactory status. However, the future holds great promise with the integration of artificial intelligence algorithms and the recognition of olfactory evoked potentials. By combining these cutting-edge technologies, it becomes possible to identify abnormalities in an individual’s sense of smell in a remarkably objective and accurate manner. This exciting development necessitates collaboration among researchers from diverse fields such as otorhinolaryngology, neuroscience, bioengineering, and bioinformatics. Another avenue of exploration is the search for biomarkers present in nasal or olfactory cleft secretions. These biomarkers have great potential as they provide a more desirable and easier means to differentiate between patients with normal olfaction and those with impaired olfaction, and so also pave the way for more personalized and precise interventions in the field of OD.
Olfactory dysfunction in patients after recovering from COVID-19
Published in Acta Oto-Laryngologica, 2020
Martin Sylvester Otte, Hans Nikolaus Caspar Eckel, Leonard Poluschkin, Jens Peter Klussmann, Jan Christoffer Luers
Among the variety of available olfactory tests, the Sniffin' Sticks test offers the most comprehensive assessment, as it includes a threshold, a discrimination and an identification test and can thus validate both the function of the peripheral olfactory system and the more complex central processing [19]. We were able to show that all three dimensions of olfactory sense were still significantly reduced in half of the patients almost two months after the onset of symptoms. Furthermore, there was no correlation between the duration of the olfactory disorder and the TDI value in the patients with persistent olfactory disorder, so that no reliable conclusions can be drawn as to whether the value in this group improves over time. Although this assumption is reasonable, it is also possible that there may be patients who fully recover from the olfactory disorder after a short time and others who do not recover after several months.
Related Knowledge Centers
- Glomerulus
- Memory
- Olfactory Bulb
- Olfactory Receptor
- Olfactory System
- Pheromone
- Taste
- Special Senses
- Odor
- Nasal Cavity