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Designing for Head and Neck Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
Feel the tip of your nose. The rounded skin-covered cartilage structures at the sides of the nose are called wings. Run your finger along the central ridge on the underside of the nose, above your upper lip. This feature is the inferior aspect of the septum, a cartilage and bony structure which separates the left and right nostrils and nasal cavities. Vibrissae, hairs inside the nostrils, offer some protection from small airborne particles. Olfactory cells (the nerve cells responsible for the sense of smell) are found in the upper reaches of the nasal cavities and communicate information about odors to the brain via the olfactory nerves (Figure 3.10, upper section). The frontal lobe of the brain lies in the cranial cavity above the roof of the nasal cavities. The sinuses are cavities in the skull located above and below the eyes, as well as deep inside the skull (Figures 3.2, 3.7, and 3.10). The pharynx, commonly called the throat, is a muscular structure which funnels air, liquids, and solids to the appropriate locations in the neck. It includes the nose (nasopharynx) and mouth (oropharynx). In the neck, the laryngopharynx, the lowest region of the pharynx, is behind the voice box.
Hearing, Proprioception, and the Chemical Senses
Published in Robert W. Proctor, Van Zandt Trisha, Human Factors in Simple and Complex Systems, 2018
Robert W. Proctor, Van Zandt Trisha
We can smell substances that are volatile; that is, they can evaporate. Air currents carry the molecules to our nose, where they affect smell receptors. The receptor cells are located in a region of the nasal cavity called the olfactory epithelium. Each receptor cell has an extension, called an olfactory rod, which goes to the surface of the epithelium. The olfactory rod contains a knob near its end, from which hairlike structures, olfactory cilia, protrude. These cilia are most likely the receptor elements. Like the taste receptors, smell receptors have a limited lifespan. They function for about 4–8 weeks. The axons from the smell receptors make up the olfactory nerve, which goes to the olfactory bulb at the front of the brain. The primary route from the olfactory bulb to the cortex is called the lateral olfactory tract.
Clinical Effects of Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
This mechanism (just discussed) includes the nose when pollutants go right up the olfactory nerves to the hypothalamus. This pathway and the respiratory pathway are the two largest pathways through which inhaled pollutants enter the body. The GI tract is the third largest though through a circuitous peripheral route. Skin, bladder, and vaginal absorption also can absorb, but these routes are usually slower and at times milder though the chemically sensitive can react severely at times. Recent studies by Kissel et al.16 show that phthalates that are endocrine disruptors are absorbed through the skin. The olfactory nerve may become hypersensitive to any pollutant odor including toxic volatile organic and inorganic odors including car exhaust, pesticide, natural gas, mercury, lead, and mycotoxins, etc., all creating the chemically sensitive individual (locally in the nasal membrane and olfactory cells) or by transmitting impulses from the olfactory membrane and cells across the cribriform plate to the olfactory bulb and nerve into the prefrontal brain olfactory area and hypothalamus. This odor then can trigger a series of adverse responses in the frontal lobe like short-term memory loss, confusion, weakness, and fatigue including limbic abnormalities such as vegetative functions, endocrine functions, body temperature (low or high), emotional behavior, motivational drives, and eventually autonomic functions and dysfunctions as well as motivational misbehavior.
Analytical essay on the faculties of the soul
Published in Annals of Science, 2023
Bonnet follows Condillac’s procedure by presenting his innervated statue with a rose. Its fragrant corpuscles stimulate certain branches of the olfactory nerve leading to the brain. There is a sensation of the smell of a rose, but the statue is not aware that it is having an experience because it lacks the ability to reflect on itself as an entity. When the rose is removed, the sensation of smell fades, but an effect on the fibres remains; they have been modified so that they are disposed to be excited in the future even in the absence of the external stimulus: this is memory. There is an entire library of nerve fibres differentially sensitive to individual smells, notes and tastes (Sections 84–85). Pleasure and pain are explained by the degrees of agitation the fibres undergo, and Bonnet offers us fibre-based explanations of aesthetic experience, the enjoyment of novelty, the enjoyment of moral beauty (Section 376), and also sensory fatigue and ennui. Consciousness, as in Condillac, is identified with attention. Genius depends on the solidity and forcefulness of a person’s brain fibres. Even the achievements of a Newton are just the lucky result of having a certain type of brain that makes novel connections between ideas (Section 330).
Effect of head impacts and chemical irritation on elite athletes’ olfaction
Published in European Journal of Sport Science, 2023
Iida-Kaisa Manninen, Laura K. Mäkinen, Pippa Laukka, Tuomas Klockars, Karin Blomgren
Limited research exists on athletes’ olfaction. In one study, boxers had decreased olfactory threshold and odour identification compared with a control group, but no difference in odour discrimination was noted (Vent et al., 2010). In addition, former National Football League players had a somewhat lower odour identification score than controls (Alosco et al., 2017). These changes may be a result of head trauma caused by repetitive head impacts (Deems et al., 1991; Harris et al., 2006). Trauma can affect the sense of smell at different levels: it may cause nasal obstruction through nasal deformities (fracture or soft tissue trauma; Kim et al., 2017) shear or stretch of olfactory nerve fibres at the cribriform plate or contusion/haemorrhage at the olfactory bulb or cortex (Howell, Costanzo, & Reiter, 2018; Leopold & Holbrook, 2010).