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The Excessive Gagging Reflex
Published in Eli Ilana, Oral Psychophysiology, 2020
The gag reflex is normally activated when there is a drastic, immediate need to protect the airway and to remove noxious stimuli from the gastrointestinal tract. It is usually triggered by a stimulus in the posterior oral cavity or pharynx, in order to eructate or eliminate the stimuli.2 Gagging is associated with other reflexes of the oropharynx (i.e., swallowing and vomiting), all part of the reflexes integrated in the medulla oblongata. Swallowing is triggered by afferent impulses in the trigeminal, glossopharyngeal, and vagus nerves. The efferent fibers pass to the pharyngeal musculature and the tongue via the trigeminal, facial, and hypoglossal nerves. It is initiated by the voluntary act of propelling the oral contents toward the back of the pharynx. This starts a wave of involuntary contractions in the pharyngeal muscles that pushes the material into the esophagus. Inhibition of respiration and glottic closure are part of the swallowing reflex response.3
Respiratory Medicine
Published in Stephan Strobel, Lewis Spitz, Stephen D. Marks, Great Ormond Street Handbook of Paediatrics, 2019
Colin Wallis, Helen Spencer, Sam Sonnappa
This should include an upper gastrointestinal contrast study to evaluate oesophageal motility and to rule out underlying anatomical defects such as hiatus hernia, pyloric narrowing resulting in hold up to gastric emptying or malrotation of the upper small bowel. A video fluoroscopy study examines the swallowing reflex in specific detail especially with different consistencies of food including liquids, semi-solids and solids. This will demonstrate spill-over or recurrent aspiration into the trachea and also the efficiency of the cough reflex in the face of such stimulation. A particularly severe example is illustrated in Fig. 4.27. A tracheo-oesophageal fistula requires specific investigation with a tube oesophagram carried out by an experienced radiologist. Gastro-oesophageal reflux also requires investigation with a pH study, sometimes in combination with impedance measurements or a radio isotope milk scan. There is no gold standard test to prove that aspiration has occurred. There is interest in the value of alveolar lavage sampling for chemicals such as pepsin or cytological evaluation of lipid laden macrophages.
The digestive system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
The esophageal stage of the swallowing reflex involves a primary peristaltic wave of contraction that is initiated by the swallowing center and mediated by the vagus nerve. This wave, which begins at the UES, moves slowly down the esophagus at a rate of 2–6 cm/s until it reaches the LES. Therefore, it may take a bolus of food 10 s to pass through the esophagus. Some food particles that are particularly large or sticky may remain in the esophagus after the primary peristaltic wave. The distension of the esophagus by the presence of these particles elicits secondary peristaltic waves that do not involve the swallowing center. The smooth muscle of the LES relaxes immediately prior to the arrival of the peristaltic contraction to allow for the movement of the food into the stomach.
Current status and advances in esophageal drug delivery technology: influence of physiological, pathophysiological and pharmaceutical factors
Published in Drug Delivery, 2023
Ai Wei Lim, Nicholas J. Talley, Marjorie M. Walker, Gert Storm, Susan Hua
Saliva production in a healthy individual is about 0.5 to 1.5 L a day (Iorgulescu, 2009). The flow rate of saliva in the oral cavity varies depending on the physiological state of an individual. In the unstimulated state, the flow rate of saliva is about 0.3 to 0.4 mL/min and this increases to 4 to 5 mL/min in the stimulated state (e.g. eating and chewing) (Iorgulescu, 2009). During the resting state or sleep, the flow rate of saliva decreases significantly to about 0.1 to 0.25 mL/min (Iorgulescu, 2009). The swallowing reflex is usually triggered when the volume of saliva in the oral cavity reaches about 1.1 mL, which causes the saliva to wash over the mucosa during transit through the esophagus (Iorgulescu, 2009). The number of swallows a person makes when awake is about 20 to 350 times an hour compared to approximately 3 times per hour when asleep (Sato & Nakashima, 2006). Therefore, the continuous washing of saliva through the esophagus is a significant challenge for effective topical drug delivery. Drugs formulations will need to have sufficient retention to the esophageal mucosal surface to avoid being washed down the GI tract (Batchelor et al., 2004).
Incidence and Prevalence of Infectious Diseases and Their Risk Factors among Patients Who Use Visiting Nursing Services in Japan
Published in Journal of Community Health Nursing, 2020
Kyoko Noguchi, Ryota Ochiai, Yoko Imazu, Yuri Tokunaga-Nakawatase, Setsuko Watabe
In this study, the inability to perform oral self-care was indicated as a risk factor for contracting infectious diseases. An appropriate practice of maintaining oral care is crucial in preventing aspiration pneumonitis. Takayasu et al. (2017) demonstrated that the number of bacteria in the saliva varies during the day and that Streptococcus, the major cause of aspiration pneumonitis, proliferates during the night. Additionally, the activity of the brain’s deglutition center declines while sleeping. Given that swallowing declines among the elderly in the form of delays in initiating the swallowing reflex, aged patients are most prone to experience silent aspiration (Logemann, 1990; Tracy et al., 1989). The study by Vysniauskaité et al. (2005) stated that elderly individuals who have 21 or more remaining teeth showed better oral care in the evening. This shows that performing oral care before sleep can prevent the proliferation of bacteria in the mouth during the night, which effectively prevents aspiration pneumonitis. As such, it is necessary to instruct patients and their caregivers of the necessity of performing oral care, especially before sleeping.
Daily auricular stimulation with capsaicin ointment improved cough reflex sensitivity in elderly patients with dysphagia: a pilot study
Published in Acta Oto-Laryngologica, 2020
Hiroki Ohnishi, Osamu Jinnouchi, Seiji Agawa, Eiji Kondo, Ikuji Kawata, Hidehiko Okamoto, Takahiro Azuma, Go Sato, Yoshiaki Kitamura, Koji Abe, Noriaki Takeda
The swallowing function consists of four subfunctions: (1) sensory initiation of swallowing reflex; (2) motion to hold a bolus in the oral cavity and to induce laryngeal elevation; (3) glottal closure and cough reflexes; and (4) pharyngeal clearance of a bolus into the esophagus [9]. Therefore, we used the SMRC scale to evaluate the four subfunctions of the swallowing function on videoendoscopy separately: (1) Sensory: initiation of swallowing reflex as assessed by endoscopic whiteout; (2) Motion: holding a bolus in the oral cavity and inducing laryngeal elevation according to instructions; (3) Reflex: glottal closure and cough reflexes induced by touching the epiglottis or arytenoids with endoscope in the touch methods [11]; and (4) Clearance: pharyngeal clearance of a bolus after swallowing (Table 1). Accordingly, we used the reflex score of the SMRC scale as an endoscopic semiquantitative numerical index of the cough reflex sensitivity in the present study [9,10]. The increase of the endoscopic reflex score means the improvement of cough reflex.