SCIENCE

• Balanced diet


  Contains the right amounts of carbohydrates, proteins, fats, vitamins, minerals, water and fiber to supply the body with energy and materials for its activities
• Four major groups of food


  • Cereal grain group
  • Fruits and vegetable group
  • Meat and alternatives group
  • Fat, milk, salt and sugar group
• Not eating a balanced diet


  Health problems are often encountered
• Malnutrition


  A condition acquired when people do not take the right kind of food
• Overnutrition


  Eating too much can also lead to health problems
• Digestive system


  Made up of the digestive tract and other organs that help the body break down and absorb food
• Digestion in humans


  1. Feeding/ingestion

  2. Digestion

  3. Absorption

  4. Elimination
• Physical digestion


  Mechanical breakdown of food into smaller particles
• Chemical digestion


  Breakdown of complex molecules, such as proteins, starch, and fats contained in food, into simple, soluble molecules
• Mouth


  The first part of the digestive tract, adapted to receive food by ingestion, break it into small particles by mastication, and mix it with saliva
• Pharynx


  The part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea
• Esophagus


  A muscular tube connecting the throat (pharynx) with the stomach
• Stomach


  A J-shaped organ that digests food, producing enzymes and acids to break down food
• Small intestine


  An organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place
• Parts of the small intestine

  • Duodenum
  • Jejunum
  • Ileum
• Large intestine


  The last part of the gastrointestinal (GI) tract, where food waste leaves your body
• Rectum


  A chamber that begins at the end of the large intestine, immediately following the sigmoid colon, and ends at the anus
• Anus


  The opening of the rectum through which stool passes out of your body
• Accessory glands


  The liver and pancreas are considered digestive helpers, with other functions beyond digestion
• Liver


  Your largest internal organ, located mainly in the upper right portion of your abdomen
• Pancreas


  An organ located in the abdomen, playing an essential role in converting food into fuel for the body's cells
• Absorption of food

  1. Proteins are broken down into individual amino acids

  2. Carbohydrates are broken down into simple sugars

  3. Fats are broken down into fatty acids and glycerol
• Elimination of waste materials

  1. Materials that are not absorbed in the large intestine form a solid waste known as feces

  2. Feces is stored temporarily in the rectum

  3. Feces is expelled through the anus
• Egestion


  The act of excreting unusable or undigested material from a cell or the digestive tract
• Defecation


  The final act of digestion, by which organisms eliminate waste material known as feces from the digestive tract via the anus
• Bowel movement


  The last stop in the movement of food through your digestive tract
• Time food stays in digestive organs

  • Mouth: 5-30 seconds
  • Esophagus: 7-10 seconds
  • Stomach: 2-24 hours
  • Small intestine: 3-5 hours
  • Large intestine: 18 hours-2 days
• Assimilation


  The process of transport and use of absorbed nutrients
• Sugars


  Simple sugars are converted into glycogen and stored in the liver, while glucose is carried in the blood to be distributed throughout the body and used for energy production
• Amino acids


  Upon entering cells, they are converted as new protoplasm and used for growth and repair, as well as for the formation of enzymes and hormones
• Fats


  Brought to the liver where they are converted into forms that can be oxidized or stored, and used to build protoplasm in cell membranes
• Due to modern lifestyle, diseases of the digestive system disorders known as gastrointestinal diseases, are becoming common today
• Common symptoms of digestive system disorders

  • Change in bowel habits
  • Sudden weight loss
  • Severe abdominal pain
  • Blood in the stool
  • Heartburn and release of gas
• Diarrhea


  Occurs when the lining of the large intestine cannot maintain the usual level of water absorption, thus secreting more than the normal quantity of water, ions, and mucus
• Constipation


  Occurs when the peristalsis moves the stool in the colon too slowly, causing the colon to reabsorb too much water and the stool to become hard and compacted
• Hepatitis


  Inflammation of the liver caused by excessive consumption of alcohol or a viral infection, resulting in symptoms like nausea, fever, loss of appetite, abdominal pain and jaundice
• Types of hepatitis

  • Hepatitis A (infectious hepatitis)
  • Hepatitis B (serum hepatitis)
• Gallstones


  Crystals formed by too much cholesterol, bile salts, and calcium in the gall bladder, causing sporadic pains in the upper abdomen or below the right ribs
• Peptic ulcer


  Open sores found in the esophagus, stomach, and duodenum, caused by the presence of the Helicobacter pylori bacteria
• Hemorrhoids


  Inflamed and enlarged rectal veins, occurring after straining and eliminating hard stools