Biology - The Digestive System

• Digestive system is responsible in digesting the food that we eat in a

  process known as digestion. It breaks down food particles to organic

  compounds that can be used by the cells in the body.
• Digestive system has two ways in breaking down food: mechanical digestion and chemical digestion.
• When the food is broken down into smaller pieces through chewing,

  grinding, squeezing and tearing, this is called mechanical digestion.
• When the food is broken down with the help of chemicals and other

  substances to liquefy, it is called chemical digestion.
• Digestive system is composed of two groups. One group

  makes up the gastrointestinal tract which includes the mouth, esophagus, stomach and intestine. The other group stores, release and makes up chemicals that aids the further break down of food composed of the following: pancreas, liver, gall bladder and salivary glands
• Complete digestion takes place when the food enters the mouth, passes a long tube and then exits as feces or stool in the anus.
• Incomplete digestion is when there is only one opening in the digestive system in which this opening serves as the mouth and the anus of the organism.
• Mouth. This is where digestion begins.
• Ingestion happens when food is ingested or taken in into the mouth. It is where the food is broken down into smaller pieces by chewing, tearing, and grinding the food and changing the food physically. After it has been broken down mechanically the salivary glands now produce a chemical that will start breaking down the carbohydrates from the food.
• Pharynx. It is a hollow tube inside the neck. It is about 5 inches long

  and also known as throat. It is a part where it propels or moves the pieces of food down to the esophagus.
• Esophagus. This is a tube that creates a connection from the mouth

  to the stomach. It serves as the passageway of the food and where peristalsis begins.
• Peristalsis is the involuntary movement that involves alternating waves of contraction or strong motion that moves the food swallowed from the esophagus to the stomach until it reaches the small intestine.
• Stomach. It is a bag-like organ in the digestive system which is responsible in grinding and mixing the food together with the digestive juices or enzymes.
• Hydrochloric acid is released in this organ

  and converts the food into a soupy substance called chyme. It is the product of digestion in the stomach.
• Gastric juices. These juices are responsible in the start of breaking down proteins. The stomach works for about four (4) hours then pushes the food into the small intestine.
• Small Intestine. Chemical digestion mostly happens in this organ. It

  contains several digestive juices. The juices are responsible in digesting the proteins into amino acids and some digest carbohydrates into simple sugars.
• Liver. It is the largest solid internal organ of the body. This organ

  secretes bile which is a green liquid that breaks up fats into smaller droplets and serves as storage of nutrients.
• Gall Bladder. It serves as storage and concentration of bile. The bile

  is stored here until it will be needed by the small intestine for digestion of fats.
• Pancreas. It is a small sac found in the digestive system. This is a gland that is responsible in converting the food to fuel the body cells. It makes digestive juices each day during digestion. Its main function is to help digestion and is also vital in regulating blood sugar.
• In the small intestine, absorption happens. The nutrients from the food will be absorbed by the bloodstream which allows the circulatory system to take its responsibility in circulating and delivering

  the nutrients throughout the body. The circulated nutrients will now be

  assimilated.
• Assimilation is the process where the nutrients delivered by the

  bloodstream reach the cells to provide them cells energy for growth and for repairs. When the bloodstream circulates this includes the oxygen that is needed by the respiratory system.
• Large Intestine. This organ gets the useful liquids from the undigested food. This is where dehydration and compaction of the indigestible materials happen. This time, excretion will occur where these indigestible materials called feces will solidify and will pass through the rectum and exits through the anus.
• Nutrient deficiency, or also known as nutritional deficiency,

  happens when our body does not receive or absorb necessary amount of nutrients from the food that we eat. This also means that the vitamins and minerals in our body is not enough to let it function properly. This deficiency can lead to a variety of health problems.
• Nutrient Deficiency Diseases


  Diseases around the world described because of nutritional deficiencies
• Deficiency can lead to serious health problems
• Nutrient Deficiency Diseases

  • Iron deficiency
  • Zinc Deficiency
  • Iodine deficiency
• Iron deficiency


  Insufficient iron in the body, also called anemia. Body cannot produce enough red blood cells to carry oxygen, leading to fatigue and shortness of breath.
• Zinc Deficiency

  Body does not receive adequate amount of zinc to sustain its function. Zinc supports cell functions and chemical reactions. This leads to appetite loss and poor immune system. Significant public health concern in the Philippines.
• Iodine deficiency


  Body does not have an accurate amount of iodine, mostly obtained from diet. This may result in metabolic problems such as goiter.
• Common Digestive Diseases

  • Constipation
  • Diarrhea
  • Peptic Ulcers
  • Colon Cancer
• Constipation


  Infrequent bowel movement and the stool is difficult to pass, can happen for several weeks or even longer
• Diarrhea


  Loose and watery stool that can be present for days, a result of the body's inability to absorb food
• Peptic Ulcers


  Painful sores inside the lining of the stomach or in the upper part of the small intestine, slow to heal and can keep on returning
• Colon Cancer


  Also known as colorectal cancer, involves the colon or the large intestine and the rectum, tumor growth in the lining of the large intestine or in the rectum, can cause abdominal pain and change in bowel habits
• Digestive System

  
• Complete Digestion