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Head and Neck
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The nasal cavity includes the bones of the lateral nasal wall and the nasal septum. The lateral nasal wall includes the cribriform plate superiorly, the intricately swirled superior nasal concha (concha = “shell shaped,” to increase surface area for air circulation, warming, and decontamination; inferior to the sphenoethmoidal recess) and the middle nasal concha (inferior to the superior meatus) of the ethmoid bone. The lacrimal bone (a small fragile bone descending from the orbit) and the inferior nasal concha (inferior to the middle meatus and superior to the inferior meatus) are the other two bones populating the lateral nasal wall. Posteriorly, one can find the opening of the sphenoidal sinus, sphenoid body, medial plate of the pterygoid process of the sphenoid bone, the sphenopalatine foramen as described earlier, and the perpendicular plate and horizontal plate of the palatine bone (Plates 3.9 and 3.38). The vestibule (meaning, “the space between the entrance and the interior”) is anterior to the inferior meatus and the atrium (“open space”) is anterior to the inferior meatus. The position of nasal choanae (the caudal openings of the nasal passages) shifts caudally with the formation of the secondary palate.
Disorders of Sensation, Motion, and Body Schema
Published in Rolland S. Parker, Concussive Brain Trauma, 2016
Olfaction is a sensation taken for granted; its loss creates both danger and reduced quality of life. It was among the first brain structures developed in primitive animals, and much of the remainder of the brain has been organized around it. Nevertheless, olfactory structures evolved in several different stages. The very old olfactory system subserves basic olfactory reflexes. The less old system provides automatic but partially learned control of food intake and aversion to toxic and unhealthy foods. The newer system is comparable to most other cortical sensory systems and is used for the conscious perception and analysis of olfaction (Guyton & Hall, 2006, pp. 668–670). The olfactory epithelium is located in the roof of the nasal cavity and extends onto the superior nasal conchae and the nasal septum. Neurosensory cells assemble into about 20 bundles, which traverse the cribriform plate of the ethmoid bone to synapse on the olfactory bulb located on the ventral surface of the frontal lobes. This proceeds posteriorly and then divides, with one branch decussating contralaterally via the anterior commissure and the other branch proceeding to the medial surface of the frontal lobes (stirring emotional responses of the limbic system), and to the temporal lobe (uncus, entorhinal area, the insular junction with the frontal lobe, and the amygdaloid body). The central mechanisms by which the brain recognizes and discriminates attractive and repulsive odorants and tastants, and thus makes behavioral decisions, are not well understood. Selective frontal lobe damage can cause defective odor quality discrimination without a decrease in odor detection (Damasio & Anderson, 2003). Aversive stimuli can create a false impression of olfactory capacity through the stimulation of the trigeminal nerve in the nasal mucosa.
Nervous system
Published in David Sturgeon, Introduction to Anatomy and Physiology for Healthcare Students, 2018
Before we examine the different regions of the brain, it is worth quickly considering the five special senses. As noted above, they consist of touch, taste, smell, sound and sight. In Chapter 3, we saw that nerve endings situated in the dermis of the skin (and elsewhere) transmit sensory nerve impulses relating to pressure, pain and temperature, towards the central nervous system. These signals are interpreted by the primary sensory cortex (situated in the parietal lobe of the cerebrum) discussed below. Our sense of taste (gustation) and smell (olfaction) are closely linked because both use chemical receptors (chemoreceptors) to generate sensory information/nerve signals. In Chapter 11, we noted that taste buds (papillae) are situated on the tongue and, to a lesser extent, on the roof of the mouth (palate) and in the pharynx. These tiny, peg-like projections give the tongue its slightly abrasive feel and respond to five taste sensations: salty, sour, bitter, sweet and umami (a word derived from the Japanese for ‘delicious taste’). Salty taste is largely produced by sodium ions (Na+) dissolved in solution/saliva and sour taste by hydrogen ions (H+). Bitterness is the most sensitive of the tastes and is thought to warn of potentially toxic ingredients. However, many food and drinks also have a bitter quality including coffee, turmeric, rocket, etc. Sweet taste is produced by the presence of saccharides and a few other substances including aldehydes and ketones. Finally, umami is usually described as a ‘savoury’ or ‘meaty’ taste and cannot be replicated by combining the other four tastes. Umami is essentially the taste of glutamate found in fish, mushrooms, tomatoes, beans and many fermented foods including soy sauce, cheese and Marmite. Monosodium glutamate (MSG) is often added to food as a flavour enhancer. The mouth and tongue also contain mechanoreceptors, nociceptors and thermoreceptors which indicate when food and drink is hot or cold. All five taste sensations are enhanced and influenced by olfaction and if you lose your sense of smell, or simply hold your nose when eating, taste is impaired. It is estimated that about 80% of taste is actually smell, so to speak. The olfactory receptors cover the superior nasal concha on either side of the nasal septum (see Chapter 9, Figure 9.2) and detect airborne chemicals (odorants) that have been dissolved in mucus. Once a nerve impulse has been generated, it is driven towards the limbic system via the olfactory bulb discussed in more detail below. The location of the olfactory receptors within the nose means that we often have to sniff to ensure odorants can be detected. Interestingly, the mucus that ‘captures’ and dissolves these chemicals is constantly renewed which means that strong or unpleasant odours are quickly reduced in intensity. This partly explains why people who work in smelly environments become desensitised to noxious odours and are still able to enjoy their lunch!
Brain targeted delivery of lurasidone HCl via nasal administration of mucoadhesive nanoemulsion formulation for the potential management of schizophrenia
Published in Pharmaceutical Development and Technology, 2020
Mrunali R. Patel, Rashmin B. Patel, Shivam D. Thakore, Ajay B. Solanki
Freshly excised sheep nasal mucosa, except septum, was collected from the local slaughterhouse and placed in phosphate buffer (pH 5.0) (PBS). The membrane was kept in PBS for 15 min to equilibrate. The superior nasal concha was identified and separated from the nasal membrane. The excised superior nasal membrane was then mounted on a Franz diffusion cell. The tissue was stabilized using the phosphate buffer pH 5.0 in both compartments and allowed to stir for 15 min on a magnetic stirrer (Multimagneic stirrer, DBK, India). After 15 min, the solution from both compartments was removed and fresh diffusion media (phosphate buffer pH 5.0: transcutol® P, 1:1 v/v) was filled in the receptor compartment. The mounting of the nasal membrane was performed by applying glue to the brim of the donor compartment to avoid leakage of the test sample and supported with thread crossing over the cell (Patel et al. 2016a, 2016b).
An expansive aneurysmal bone cyst of the maxillary sinus in an 8 year old child: Case report and review of literature
Published in Acta Oto-Laryngologica Case Reports, 2020
Milan Urík, Ivo Šlapák, Michaela Máchalová, Jana Jančíková, Soňa Šikolová, Denisa Pavlovská, Petr Jabandžiev, Marta Ježová
A gingivobucal mucosa was cut and an opening was made into the maxillary cavity through its anterior wall. We performed curettage of the cavity, destruction of the posterior, upper and medial wall of the maxillary cavity was evident. Healing again proceeded without complications, unfortunately after 2 months the disease recurred again. We revised again from the external approach, almost total destruction of the front wall of the maxillary cavity was evident, the cavity was so wide opened and the cyst could be removed in its entirety, and a part of the upper wall of the maxillary cavity was destroyed. We also removed part of the lower and superior nasal concha and created a wide communication to the nose. At the end of the operation, we repeatedly flushed the cavities with antibiotic solution and inserted the tamponade. The healing was without complications. The patient is monitored regularly, the swelling of the face and eyelids gradually disappeared, subjectively the patient is without any problems, the MRI control examination showed that the disease does not recur (Figure 6).