This essay will be reviewing the gastrointestinal tract (GI tract), looking at the components and their functions. It will explore how the system works, how it can be assessed by a clinician and the ethical and practical issues related to when assessing the GI tract. In relation to this, I will also be analysing how the endocrine system and autonomic system correlate to the gastrointestinal tract.How it functionsMarieb (2016) states that the gastrointestinal tract (alimentary canal) is a long tube that goes from the mouth to the anus. The main function of the GI tract is to transport, digest and absorb food. The components of the GI tract are- the mouth, pharynx, oesophagus, stomach, small intestine and large intestine. The function of the GI tract is to digest the food, it takes place in six processes: ingestion, propulsion, mechanical breakdown, digestion, absorption and defecation. These processes are all necessary for the GI Tract to function. The GI tract is made up of mucosal layer that consist of epithelium. The middle layer is the submucosal layer. The outermost layer is the muscularis external layer which is the muscle that moves the food.The first stage of beginning of the GI tract is the mouth (oral cavity), its role is to chew (mastication) food down, so that it is easier to swallow (Marieb, 2016). The oral cavity contain accessory organs such as teeth, tongue and salivary gland and all help with the process of moving the food to the next process. Once the food is swallowed, it will go through a process called voluntary phase, which involves the formation of the bolus food. The tongue then projects the food backwards and forwards, with it eventually travelling to the pharynx. The soft palate would elevate, and this will prevent food travelling to the nasal cavity and not allow respiration to occur during that process. (Ward and Linden, 2017) .The pharynx is located in the neck and throat and is a funnel shaped tube, its function is to move food from the mouth to the oesophagus. Additionally, the pharynx also important in the respiratory system when air from the nasal cavity travels through the pharynx to larynx and eventually to lungs. Here there is a epiglottis, a flexible flap that act like a moving barrier between the larynx and oesophagus. The oesophagus is a long hallow muscular tube that allows food to pass through from the pharynx to the stomach. Once the food enters the oesophagus, the upper oesophageal sphincter relaxes and this is when food enters the oesophagus and then immediately contracts. The food will travel through the oesophagus through a peristalsis wave and allowing the food to travel to the lower oesophagus sphincter and finally arrive at the stomach (Marieb, 2016).According to Marieb (2016), the stomach is a hallow muscular organ that is located below the diagram and just above the small intestine. The function of the stomach is to receive the food from the oesophagus and to begin mechanical and chemical breakdown of the food, and then turn the bolus into chime. The stomach regulation occurs in three phases. It begins with the cephalic phase, when your brain detects food through smell, taste and thought of food, the cerebral cortex will relay the signal to the hypothalamus, which will stimulate the medulla oblongata and this will travel through the vagus nerve and to finally the signal reaching the stomach (Marieb, 2016) At this point, the stomach will prepare itself for the oncoming food. Once the food reaches the stomach, gastric phase is initiated and the stomach will distend the food and stretch receptors are activated and this will stimulate the medulla to send impulses to the stomach via vagal fibres to release gastric juices (Marieb, 2016). G cells in the lining of the stomach will release gastrin and will stimulate gastric glands to produce more gastric juices. Parietal cells will release hydrochloric acid, and this will help change the shape of proteins so that enzymes can digest them (Ward and Linden, 2017). Gastrin is inhibited when the pH drop down to 1.5 (Ross and Wilson, 2014). The food in the stomach will turn into chyme and this will proceed onto the small intestine via the pyloric sphincter.According to Caroline (2014), the small intestine is where the chemical breakdown of food and where a large amount of absorption of water, fats, proteins, carbohydrate and vitamins take place. The small intestine is located in the central, upper umbilical. When the chyme enters the duodenum, two hormones will be produced: secretin and cholecytokin. These hormones will inhibit gastric secretion and gastric motility and therefore the chyme will mix with the bile and pancreatic juices (Ross and Wilson, 2014). The small intestine is lined with epithelial tissues and even closer are villi and micro villi, which create a large surface area for the small intestine which allow it to absorb nutrients. The duodenum receives bile from the liver and gallbladder, pancreatic juices and pancreatic enzymes. The pancreatic juices contain bicarbonate ions which are alkaline and when mixed with bile and pancreatic juices it will create a pH of 6 to 8 which allow pancreatic enzymes to function ( Ross and Wilson, 2014). The jejunum is where majority of the nutrients are absorbed and ileum is where absorption of vitamins such as A, B12, E, D, K take place ( Ross and Wilson, 2014)The large intestine function is to absorb any remaining water, formation of faeces and good bacteria for digestion. It consists of the colon, rectum and anus (Ward and Linden, 2017). Additionally, if the absorption of water does not occur, this could lead to constipation or diarrhoea. The bacteria in the large intestine produces vitamins like K and B12. They also breakdown cholesterol, drugs and food additives (Ward and Linden, 2017). The faeces will travel through the colon and go through slow segmenting haustral contraction, this process will generally happen every 30 minutes and go on for about 1 minute. Peristalsis movement does occur once you have just eaten and move the faeces to the rectum where it is stored and then to anus and out (Marieb, 2016).Endocrine and autonomic systemThe endocrine system and the autonomic system is required for the functioning of the gastrointestinal system. The endocrine system supplies hormones such as cholecystokinin, gastrin and secretin, which has been explored in the stomach and small intestine section. The autonomic system has a subdivision called the enteric nervous system, it consist of two internal nerve plexuses; myenteric and submucosa, which are found in the walls of the alimentary canal. The submucosa nerve plexus function allows absorption, secretion and muscle movement. The myenteric nerve plexus function is for the motility of the gut (Marieb, 2016)Assessment and ethical issuesWhen the clinician arrives at a scene, they need to ensure that they follow the DRABC sequence, this will help the clinician distinguish if the patient is critical or non-critical (Blaber and Harris, 2016). The clinician then needs to ask the patient about current issues/illness, past medical history, family history and social history, to workout what is normal and abnormal for the patient (Caroline, 2014). The abdomen has 4 quadrants, right upper quadrant, left upper quadrant, right lower quadrant and left lower quadrant (Caroline, 2014). The clinician will move onto physical examination where they will inspect the abdomen, assessing the four quadrants and looking out for any bruising, scars and strae (Caroline, 2014). The clinician would then proceed onto auscultating, looking out for any abnormal sounds and then palpate to look out for any tenderness (Caroline, 2014). When looking into the practical and ethical issues related to examining of the gastrointestinal tract, there are a number of things to consider. In order to find out the underlying issues of the patient, you need to get consent before proceeding to examine, this needs to be informed and valid (Blaber and Harris, 2016). Since the area that needs to be examined is the gastrointestinal tract, the abdominal area will need to be exposed, the clinician needs to address the dignity of the patient at all cost ( Caroline, 2014). There may be occasions where patients may not have the capacity, so doing what is best interest of patient is vital ( Caroline, 2014). Furthermore, the clinician will ask the patient a number of questions about bowel movements and family history, since these may be sensitive topics it is important to note if the patient feels uncomfortable or unwilling to share. Therefore clinicians must take the local surroundings and the presence of others into consideration ( Blaber and Harris, 2016). This essay has reviewed the gastrointestinal system, linking with the endocrine and autonomic systems. It looked at how we assess the system and any practical & ethical issues outcome of this.