Oral Biofilms and Their Implication in Oral Diseases
Chaminda Jayampath Seneviratne in Microbial Biofilms, 2017
The oral cavity is the beginning of the digestive system and forms an intersection with the respiratory system. It is inhabited by a plethora of microorganisms that are collectively referred to as the ‘oral microbiota’ or the ‘oral microbiome’. Most bacteria are transiting through the oral cavity rather than successfully residing in it. Physiological factors, such as salivary flow and shearing forces, or microecological factors, such as redox potential, partial oxygen pressure, pH and nutrient availability, define whether a microorganism is suitable for surviving in the environment of the oral cavity. Host-related factors, such as the local immune response, hormonal changes, aging, smoking and drug consumption may also influence the composition of the oral microbiota. The capacity of a microorganism to adhere onto, for instance, a tooth surface is an important initial step, but its ability to grow onto that surface is instrumental for its survival and adaptation into the oral cavity. Hence, despite their large diversity, oral microbes in fact exhibit a high tropism for their particular ecological niche.
Rethinking Illness
Phoebe S. Prosky, David V. Keith in Family Therapy as an Alternative to Medication, 2004
In traditional Chinese medicine, the digestive and reproductive systems are the foundational systems of the human body: people need to live and to continue to reproduce. All the other systems revolve around these two. As we know, a healthy digestive system is essential to maintaining life, for it converts food into materials that build and fuel our body's cells. It is also a complicated organ system which takes food in, digests and breaks it down, absorbs the nutrients into the blood stream, and gets rid of the indigestible portion. Not surprising in a modern society such as ours in which food is abundant, many diseases of the digestive system are primarily related to “indigestion.” Indigestion arises when we eat something that doesn't agree with our stomach, whether it is too cold, too hot, too spicy, too oily, or too salty. Indigestion can also occur if we ingest toxic materials, such as some food additives.
Assessing the Toxic Load and Detoxification Strategies
Len Wisneski in The Scientific Basis of Integrative Health, 2017
The role of the digestive system in overall health is difficult to overstate. Unhealthy bowels can indeed be a significant source of metabolic toxins from both “normal” and “abnormal” gut bacteria. When the microorganisms die, toxins are secreted and released into the surrounding environment. These toxins are known as endotoxins. Technically only bacterial lipopolysaccharides (LPS) are known as endotoxins, however, it is clinically relevant in this context to use a broader definition including anything harmful released by gut bacteria. Endotoxins bind to receptors initiating an adaptive immune response and a signaling cascade leading to activation of pro-inflammatory genes.30 Impaired digestive function along with gut-derived microbial toxins trigger both the onset and maintenance of chronic low-grade inflammation.31 This, in turn, enhances intestinal permeability increasing the translocation of microbiome-derived LPS to the bloodstream resulting in a two to threefold increase in serum LPS concentration which can reach a threshold named “metabolic endotoxemia” (ME). ME may trigger toll-like receptor (TLR) 4-mediated inflammatory activation, eliciting a chronic low-grade pro-inflammatory and pro-oxidative stress.32,33 ME is associated with the development of several chronic conditions including obesity, cardiovascular disease, diabetes/insulin resistance, and nonalcoholic fatty liver disease.34
Severity scoring systems for radiation-induced GI injury – prioritization for use of GI-ARS medical countermeasures
Published in International Journal of Radiation Biology, 2023
Doreswamy Kenchegowda, David L. Bolduc, Lalitha Kurada, William F. Blakely
Life-threatening ionizing radiation exposure involves multiple organs, including the gastrointestinal (GI) system (Friesecke et al. 2001; Kiang and Olabisi 2019). The digestive system is composed of the GI tract and GI accessory organs (Table 1, Figure 1). The GI tract is among the most radiosensitive organ systems in the body, with the duodenum the most radiosensitive region of the digestive tract. The intestinal epithelial cells provide a physical and biochemical barrier that segregate host tissue and bacteria to maintain intestinal homeostasis. Radiation can cause crypt cell killing, injury to intestinal epithelial cells, and other effects resulting in a wide range of clinical manifestations, as illustrated in Table 1 (Shadad et al. 2013). See reviews on GI-radiation toxicity (Somosy et al. 2002; Hauer-Jensen 2007) and GI acute radiation syndrome (GI-ARS) (Macià I Garau et al. 2011; MacVittie et al. 2012, 2019; MacVittie and Jackson 2020).
Critical roles of adherens junctions in diseases of the oral mucosa
Published in Tissue Barriers, 2023
Christina Kingsley, Antonis Kourtidis
The oral cavity serves as the entry point for the digestive system. As a part of the body directly exposed to environmental cues, to nutrients, and to pathogens, it plays critical roles in health and homeostasis. Anatomically, the oral cavity begins with the lips, which open to the vestibule, the area between the cheeks, teeth, and lips (Box 1; Figure 1). The main area of the oral cavity, or oral cavity proper, consists of the tongue and the alveolar processes containing the teeth. Anteriorly, the roof forms by the hard palate and posteriorly by the soft palate (Figure 1). The oral cavity is protected throughout by a mucous membrane known as the oral mucosa, which is composed of stratified squamous epithelium and constitutes the inner lining of the mouth (Box 1; Figure 1).
Role of Smoking-Mediated molecular events in the genesis of oral cancers
Published in Toxicology Mechanisms and Methods, 2019
Sapna Khowal, Saima Wajid
Oral cavity (mouth or buccal cavity), forming initial contacts with tobacco smokables, plays an essential role in the digestive system. Smoking is a risk factor for precancerous and cancers ailments of the oral cavity. Nearly 50% of deaths from oral cavity cancer (oral cancer) attribute to smoking (Siegel et al. 2015). Oral cancers have shown alarming prevalence globally, affecting human populations residing in both more developed and less developed countries. Oral cancer is a sub-group of head and neck cancers. Oral squamous cell carcinoma (OSCC), arising from the abnormal squamous epithelial cells, represent the commonly diagnosed forms of oral cancers (Subramanian and Krishnakumar 2017). Smoking practiced either actively (direct/intentional inhalation of noxious tobacco fumes by smokers while using smokables) or passively (unintentional inhalation of fumes by nonsmokers while accompanying the polluted/contaminated environments), induces enhancement in the oxidative stress levels within oral cavity (localized stress) and blood circulation (systemic stress) (Comhair et al. 2011).
Related Knowledge Centers
- Gastrointestinal Tract
- Pancreas
- Digestion
- Liver
- Gallbladder
- Tongue
- Salivary Gland
- Phases of Digestion
- Gastric Glands
- Chewing