BIOS256 W1 Lab Exercise Essay

The esophagus receives food from the mouth after swallowing and then delivers it to the stomach. The stomach holds food which it is being mixed with enzymes which continue the process of breaking down the food into a useable form. When the contents of the stomach are processed they are released into the small intestine. In the small intestine food is broken down by enzymes released from the pancreas and bile from the liver, the food is moved through and mixed with digestive secretions. The small intestine is made up of three segments the duodenum, jejunum and the ileum, the jejunum and the ileum are mainly responsible from the absorption of nutrients in to the bloodstream. These contents start out semi-solid and end in a liquid form after passing through the organ. Water, bile, enzymes and mucous change its consistency, one the nutrients have been absorbed it then moves onto the large intestine. The large intestine connects to the rectum and is specialised in processing water so that emptying the bowels is easy.

The large intestine functions to absorb the remaining water from the indigestible food matter and then to pass the matter out of the body.

The process of digestion first begins in the mouth by in taking food (bolus). The teeth help with masticating (chewing and breaking food particles down) allowing for swallowing and increasing surface area for chemical digestion. Enzymes found in saliva also facilitates with the chemical break down of food primarily starches and fats. The food swallowed then enters into the esophagus (a tube connecting the mouth and stomach). Peristalsis helps the esophagus to push the food in the direction of the stomach. The stomach contents are highly acidic (doesn’t affect the stomach mucosa since cells secrete mucus allowing the stomach wall to be protected) with pH levels between 1.5-2.5 allowing microorganisms to be killed, breaking down of food, and activating digestive enzymes producing a thick substance known as chyme. However, breaking down of foods further occurs in the small intestine consisting of: bile created from the liver, enzymes formed from the small intestine, and the pancreas facilitate with further digestion as well as HCI denatures (unfolds proteins) allowing them to be available to attack by digestive enzymes (also responsible in breaking down the protein). The pyloric sphincter separates the stomach from the small intestine allowing the chime to drop into the small intestine. The small intestine is the primary site for

Once again we have been miniaturized in the submarine to continue the fantastic voyage of the digestive system. We will be touring a 55-year-old male. The host will be having a hamburger, French fries, and a root beer. We will be tracing lunch through the digestion process. Digestion is the process of turning the food that is ate into energy needed to survive and involves creating waste to be eliminated. (Mohan, 2010). The digestive tract is a long twisting tube that starts at the mouth and ends at the anus, called the alimentary canal. The wall of this tube is fashioned of four layers of tissue. The layers are listed from the inside coat to the outside coat: mucosa or mucus membrane, submucosa, muscularis, and serosa. The hollow space

The function of the Digestive System is digestion and absorption. The food is broke down and digested then absorbed by the body. The Digestive System is separated into two main parts. The digestive tract, or alimentary canal, is a continuous tube with two openings (the mouth and the anus). When food goes through the internal cavity that does not mean it enters the body until it has been absorbed through the walls and passed into the

Within the tubular gastrointestinal tract, the ENS is formed by various interconnected networks, called plexuses, of enteric neurons, glial cells, and axons (Widmaier et al. 2014). The majority of these nerve cells are found within two different arrangements of ganglia (Fig. 1): the myenteric (Auerbach’s) plexus and the submucosal (Meissner’s) plexus (Furness 2006; Guyton and Hall 2006). The nerve cells’ axons either synapse with additional neurons in the plexus or innervate the smooth muscle of digestive organs (Furness 2006). Neural activity in one plexus can affect activity in the other since some axons in one plexus synapse with neurons in the other (Fig. 1) (Widmaier et al. 2014). Extrinsic nerve fibers from the parasympathetic and sympathetic systems can also synapse with neurons in each of the two plexuses (Fig. 1) (Guyton and Hall 2006). Though the ENS can function without these nerve pathways, the subsystems of the ANS can influence gastrointestinal activity (Guyton and Hall 2006; Widmaier et al. 2014). An example would include either inhibiting or enhancing the GI tract’s motility and secretory activity through the sympathetic and parasympathetic fibers (Widmaier et al. 2014).

The digestive system is an organ system which consists of a group of organs working together to convert food into energy and nutrients which helps to maintain the body. The organs that make up the digestive system include the pancreas and salivary glands, small intestine, liver, stomach and large intestines. The function of the digestive system is to digest and absorb. Digestion is the breakdown of food into smaller molecules which are them later absorbed in the body. The digestive system is divided into two major parts: the digestive tract and the accessory organs.

The mouth is where the digestion first begins as firstly the scent of the food will travel to the nose causing the salivary glands in the mouth to produce saliva as there are three pairs that do this. As you are chewing the food with your teeth the food starts to get broken down more saliva is produced along with the breaking down. The secretion will be transferred into the mouth and the tongue as the salivary glands are causing it to do this. Also, the digestive juice contains an enzyme which is known as salivary amylase which now begins the digestion of carbohydrates as well as lubricating the mouth in order to help with the bolus formation.

The stomach is a strong muscular sac that is the mixing bowl of the body where food will be mixed with gastric acid making a liquid called chyme. Stomach muscles will continue to contract making chyme that will move to the pyloric valve, which is at the top of the small intestine, known as the duodenum. While pepsin starts the digestion of proteins and lipids begin to break apart called gastric lipase. Also very small amounts of fat-soluble molecules are absorbed through the stomach

Food begins the journal through the mouth. Inside the mouth the saliva, teeth and tongue aid in the digestion of the food by chopping the food into small pieces which are then moisturised by the saliva to help the tongue and other muscle push the food into the pharynx ( throat)

The Autonomic Nervous system (ANS) is what controls the digestive system. The ANS controls parts of the body that we do not have conscious control over. Basically, it’s things we don’t have to think about doing because the ANS automatically does it for us. The Parasympathetic Nervous System (PNS) is known for stimulating digestion by increasing blood flow to the digestive tract. The PNS increases salivary gland secretion and increases peristalsis. This helps the digestion of food and absorption of nutrients. Two types of nerves help control the digestive system. Extrinsic nerves controlled by the brain cause muscle contractions that push food along the digestive tract. Intrinsic nerves within the walls of the esophagus, stomach, small intestine,

The lower oesophageal sphincter (LOS), links the oesophagus and the stomach together and along with the upper oesophageal sphincter ensures that the movement of food within the GI tract is unidirectional (Insel, et al., 2010), (Bijlani & Manjunatha, 2010). The sphincters consist of thickened rings of circular muscle; it is these thickened rings of muscle, which allows the sphincter to carry out the movement of food into the stomach (Starr & McMillan, 2015), (Hull, 2011). Partially digested food, can move into the stomach when the circular muscles relax (due to peristalsis). When the circular muscles are contracted, they prevent the backflow (reflux) of gastric acid present in stomach (Insel, et al., 2014), (Tilanus & Attwood, 2013).

Once food leaves the mouth, it travels down the oesophagus and into the second cavity the stomach. Here digestives enzymes are released such as hydrochloric acid and gastric

The duodenum is a part of the small intestines. It helps further the process of food digestion. The duodenum gets the chyme, which is both digested food and stomach acids. The way the duodenum gets the chyme is through the pylorus. The pylorus is a valve between the duodenum and the stomach. Here, the chyme gets mixed with more digestive enzymes and intestinal juices to help digest it further. Another function of the duodenum is that is gets bile and pancreatic juice from the liver, gallbladder, and pancreas. The duodenum has more functions than just digesting the food. It also regulates gastric emptying. When the stomach empties into the duodenum, that is gastric emptying, and the duodenum controls the rate at which this happens. Another

The duodenum is the first part of the small intestine. The main role of the duodenum is to complete the first phase of digestion. In this section of the intestine, food from the stomach is mixed with enzymes from the pancreas and bile from the gallbladder. The enzymes and bile help break down food.