The Digestion Process

The Digestive System The digestive system is a system consisting of the mouth, oesophagus, stomach, gallbladder, small intestine, large intestine, the rectum and the anus. The functions of the digestive system are: • To break down food particles into molecules for digestion • To absorb into the bloodstream the small molecules produced by digestion • To eliminate un digested and unabsorbed foodstuffs and other waste products from the body The full digestive process begins at the mouth. The food enters the mouth and is chewed. This is call mastication and it gives the food a greater surface area which enables enzymes to break the food down making it easier to digest. The process of breaking down the food starts with the saliva in your mouth.

The process of digestion starts in the mouth, then makes its way to the stomach and large intestine, and concludes in the small intestine. At each step along the way, specific enzymes break down specific types of food. This process is chemically balanced as each site along the digestive tract has a different degree of acidity that allows certain enzymes to function while restraining others. Each specific enzyme can bind to only one specific substrate, or group of allied chemical substances. After leaving the stomach, food pulp enters the upper portion of the small intestine where the pancreas (digestive organ that feeds enzymes into the gut) provides pancreatic enzymes to further break down the

In the human body, one of the essential systems is the digestive system, which breaks down the foods what we eat into nutrients such as proteins, carbohydrates, vitamins and fats. The bloodstream would be absorbed by them. Therefore, it provides the body with energy, repair and growth. Also, the three types of processes that food passes through in the human body are digestion, absorption and elimination. The digestive system prepares the body cells for nutrients through six activities: Ingestion, Mechanical digestion, Propulsion, Chemical digestion, Absorption and Defecation.

The digestive systems consists of the mouth, oesophagus, stomach, liver, pancreas, small and large intestines and anus. The oral cavity is extremely vital in the process of chewing breaking down food. In addition, the saliva, which softs the food we chew comprises of enzymes that help with the process of digestion. The food that we consume goes down into the oesophagus which is basically a long tube that contains muscles which allows food down into the stomach. Both oesophagus and stomach use voluntary and involuntary movements.

Before haem iron can be absorbed, it must be hydrolysed from the globin part of haemoglobin or myoglobin; this is carried out by proteases in the stomach or small intestine. Once the haem is released from the globin, it is absorbed across the mucosal cells of the small intestine by haem carrier protein 1 (HPC1). Once absorbed, the haem molecule is hydrolysed into inorganic ferrous iron and protoporphyrin by haem oxygenase, and can be used by the intestinal cell, excreted or used by other tissues. Non haem iron must be released from food components in order to be absorbed, this process is aided by gastric secretions such as hydrochloric acid and proteases in the stomach and. Following its release from food, the non-haem iron is present in its ferric form in the stomach.

Gastric juice has a low PH of 2, and most would think why don’t our internal organs get digested due to the acidic juice that resides in our stomachs? This does not happen, because of all the cells lining our stomachs, along with a protective layer of a muscle that contains mucus that shield the lining of our stomachs. Why Aren’t Organs Digested with Stomach Acid? Animals do not digest their own internal organs due to specialty cells that are within our stomachs, like serosa, mucosa also including parietal cells, gastrin cells (g-cells) and epithelial cells. The digestive tract also produces a protective mucus that lines the stomach.

The urinary bladder is a sac-like hollow organ that is used for the storage of urine. Urine slowly fills up the bladder and stretches its elastic walls and can hold 600 to 800 milliliters of urine. The urethra is the tube that transports urine from the bladder to the exterior of the body. There are two muscles in the urethra that control the flow of the urine. They are the internal sphincter which when open results in the sensation of needing to urinate and the external urethral sphincter a skeletal muscle that will allow urine to pass through or delay urination.

Chapter Vitamin B12 Absorption and Transport in Human Body Omar Abuyaman, MSc Department of Clinical Biochemistry, Aarhus University hospital, Aarhus, Denmark. Abstract Mammals are unable to synthesize B12. Instead, they have a sophisticated multistep pathway for specific and efficient transport of this vitamin from its food source to the target body cells. Dysfunction at any of transport steps may lead to low vitamin B12 status or deficiency. Introduction The transport of B12 from its food source to reach the body cells is mediated by a complex set of carrier proteins, receptors and transporters [1].

The nerve supply also comes from her celiac plexus innervating the liver mixture of sympathetic and parasympathetic fibers. These ribs reach the liver by the hepatic artery. Liver Physiology The liver performs many functions in the body such as: • Production of bile: The liver excretes bile to the bile duct and thence to the duodenum. Bile is necessary for digestion of food. • Carbohydrate metabolism: • Gluconeogenesis: The formation of glucose from certain amino acids, lactate and glycerol.

This includes the pancreas, liver and the gall bladder. Digestion is the process of digesting food it is a process in which the food is converted or broken down into a substance that can be absorbed and assimilated by living organisms in this case it is mammals. During this process the digestive system is involved mainly the digestive

Mrs. Fender’s jaundice is caused by the accumulation of bilirubin in her blood and tissues. What is the normal fate of bilirubin, and what role does the liver play? Explain how Mrs. Fender’s cirrhosis is related to her jaundice. • Bilirubin is a product of the heme of hemoglobin formed during the breakdown of erythrocytes. The liver removes the bilirubin from the blood and excretes it into the intestines as bile.

A MacConkey plate is selective by inhibiting the growth of gram-positives and differential due to the fermentation of lactose by certain gram-negative species. In the

The stomach is a very important part of the digestive system. It is a j- shaped muscular organ that acts as a bag or sac to collect churn food with digestive juices. When the stomach is filled with food the rugae stretch out, and disappear. The food mixes with hydrochloric acid and other gastric juices to form a liquid mixture called chyme, which then passes through the remaining portion of the digestive system. So this means to me that when you eat something it goes to the stomach and is mixed with acids that breaks it down and dissolves the food.

The liver is the organ affected during an Hepatitis B infection. The liver is located in the right upper quadrant of the abdomen and has several important functions. The function of the liver is to remove excess glucose, which is also known as blood sugar, from the blood stream and stores it as glycogen ( a form of starch ). When the blood sugar level is low, the liver converts glycogen back into glucose and releases it for use by the body. The liver also destroys old erythrocytes, which are red blood cells, removes poisons from the blood, and manufactures some blood proteins.

It is produced by the gastric cells and it is formed when pepsinogen is released. When hydrochloric acid is presented, pepsinogen (inactive enzyme) will be converted into pepsin (active enzyme), which the functions is to catalyze reactions with protein.