Introduction
Shayne C. Gad in Toxicology of the Gastrointestinal Tract, 2018
Swallowing starts when the bolus is forced to the back of the oral cavity and into the oropharynx by the movement of the tongue upward and backward against the palate; these actions constitute the voluntary stage of swallowing. With the passage of the bolus into the oropharynx, the involuntary pharyngeal stage of swallowing begins. The respiratory passageways close, and breathing is temporarily interrupted. The bolus stimulates receptors in the oropharynx, which send impulses to the deglutition center in the medulla oblongata and lower pons of the brain stem. The returning impulses cause the soft palate and uvula to move upward to close off the nasopharynx, and the larynx is pulled forward and upward under the tongue. As the larynx rises, the epiglottis moves backward and downward and seals off the rima glottidis. The movement of the larynx also pulls the vocal cords together, further sealing off the respiratory tract, and widens the opening between the laryngopharynx and esophagus. The bolus passes through the laryngopharynx and enters the esophagus in 1 to 2 seconds. The respiratory passageways then reopen, and breathing resumes.
Vocal Motor Disorders *
Rolland S. Parker in Concussive Brain Trauma, 2016
Vocalization structures: The active force in the production of the voice is the airflow (Van Leden, 1961). Voice production originates from the vibration emanating from the vocal folds (Razak et al., 1983). It is then processed by the posterior oral-pharyngeal and nasopharyngeal ports (Merson, 1967). The space between the vocal folds is the rima glottidis. Its shape is determined by the position, tension, and length of the vocal cords, as well as the intensity of expiration changes in vocal pitch (Moore & Dalley, 2006, with diagrams, pp. 1089–1095). Cartilages of the larynx, trachea, and bronchia maintain the larger respiratory tubes; branchial motor axons of glossopharyngeal nerve serve the stylopharyngeus muscle that elevates the pharynx during swallowing and speech (Wilson-Pauwels et al., 1988, p. 117). The fleshy tongue manipulates the food particles to and from moving teeth on route to the mouth and throat for swallowing. Complex musculature raises and lowers the tongue, pushes it forward, and changes its shape (Butler & Hodos, 1996, pp. 56–157). The basicranial region in human infants is similar to that of monkeys and apes (see Vocalization Structures, below).
Paper 3 Answers
James Day, Amy Thomson, Tamsin McAllister, Nawal Bahal in Get Through, 2014
The larynx has intrinsic and extrinsic muscles. All intrinsic muscles, except the cricothyroid, are innervated by the recurrent laryngeal nerve. Sensation to the larynx above the vocal cords comes from the internal laryngeal nerve and below the vocal cords from the recurrent laryngeal nerve. The vestibular folds are fixed folds on each side of the larynx lateral to the vocal folds. The cricothyroid muscle supplied by the external laryngeal nerve serves to tense the vocal cords. The thyroarytenoid relaxes the cords. The lateral cricoarytenoids adduct the cords whereas the posterior cricoarytenoids abduct them. The transverse arytenoid closes the posterior part of the rima glottidis.
Global and regional connectivity analysis of resting-state function MRI brain images using graph theory in Parkinson’s disease
Published in International Journal of Neuroscience, 2021
Rutvi Prajapati, Isaac Arnold Emerson
Several studies have been reported to understand the progression of PD using brain images. The automatic segmentation algorithm is used to segment the rima glottidis area from a 4 D CT image that indicates vocal impairment symptoms. This algorithm utilizes a support vector machine (SVM) with 65% accuracy [7]. In another study, a novel pattern recognition framework is used in the sub-regions with the highest variance in SPECT intensities across PD patients, thus provide important potential biomarkers in PD progression [8]. Moreover, the molecular imaging-based PET technique investigates the texture quantification to find out the correlation between the clinical severity of Parkinson’s and texture metrics [9]. Among the entire test, EEG plays a vital role in early diagnosis. For example, the convolution neural network is established for an automatic determination of EEG signals. The accuracy of this method reached around 88.25% due to the long-term tool in PD diagnosis [10]. Also, the analysis of beta waves in EEG signals can determine the freezing of gait symptoms which is a highly debilitating and poorly understood symptom in PD [11]. Likewise, the increased resting-state functional connectivity in PD patients is observed in the MEG test using the synchronization likelihood method [12]. Compared to all the imaging techniques the EEG provides better accuracy for early diagnosis, whereas the MRI image data offers several features that help us to find a way to diagnose the progression of PD.
Construction and analysis of brain networks from different neuroimaging techniques
Published in International Journal of Neuroscience, 2020
Rutvi Prajapati, Isaac Arnold Emerson
Additionally, a novel automatic segmentation algorithm is introduced to segment the rima glottidis from 4 D CT images using texture features and support vector machine (SVM). Finding illustrates a high correlation between the manually segmented area and automatic segmentation. Utilizing the SVM algorithm on direct observation, it is well correlated with 65% subjects [135]. Moreover, a novel pattern recognition method is applied to DAT (dopamine transporter) SPECT scans and revealed that the outcome might have significant clinical implications. The enhanced clinical utility in the diagnosis as well as tracking of progression in Parkinson’s disease [136]. A high-resolution PET and MRI images of PD subjects are used to evaluate the correlation between the texture metrics and PD duration. Interestingly, they explained how the texture quantification parameters affect the relationship between texture-based image metrics and clinical disease duration [137]. The study of resting-state networks has also become an alternative method to investigate intrinsic functional connectivity in PD patients [138,139].
The laryngoscope and nineteenth-century British understanding of laryngeal movements
Published in Journal of the History of the Neurosciences, 2019
Marjorie Perlman Lorch, Renata Whurr
Ryland presented a clear summary of what was known about physiological action of the larynx from pathological cases and experiments with dogs: [M]ost of the physiologists of the present day, consider this power as residing in the thyro-arytaenoid muscles. The reasons for this belief are, 1st, the situation of these muscles, their attachment to the vocal cords, and the influence they are capable of exercising over the vibrations of these cords; 2d, the effects of the division of the recurrent nerves which supply these muscles—if both are cut the voice will cease, if only one is cut the voice will only be half lost; 3d, the loss of voice that results from ulceration, purulent infiltration, or atrophy of these muscles. ‘The extinction of the voice is carried to the highest degree, if the thyro-arytaenoid muscles have undergone any of the alterations that we have mentioned,’ observes M. [Gabriel] Andral. These observations are sufficient to prove that the contractions of the muscles in question are necessary to the production of voice, and, together with the experiments of [François] Magendie—in which the glottis of an animal being laid bare at the moment that it cried, the vocal cords were seen vibrating—show beyond all doubt that the primary tone of the voice is due to the action of the thyro-arytaenoid muscles and ligaments, and probably to their vibrating backwards and forwards, and thus alternately allowing and intercepting the passage of the air which is forcibly expelled from the lungs through the rima glottidis. (Ryland, 1837, pp. 18–19)
Related Knowledge Centers
- Arytenoid Cartilage
- Lateral Cricoarytenoid Muscle
- Posterior Cricoarytenoid Muscle
- Recurrent Laryngeal Nerve
- Vocal Cords
- Larynx
- Vagus Nerve
- Vocal Process
- Arytenoid Muscle
- Aphonia