Digestive System

• The process of digestion begins in the mouth, where food is chewed and mixed with saliva.
• Accessory organs of the digestive system include the, pancreas, liver, gall bladder, and salivary glands
• Liver creates bile which emulsifies (seperates) fat molecules
• Salivary Glands produce amylase to begin breaking down of carbohydrates into glucose
• What are the three macromolecules needed by humans?

  Carbohydrates, proteins, and lipids.
• Chemical and Mechanical digestion occurs to break large food molecules into smaller ones so cell membranes can absorb them
• What substance are involved in chemical digestion?

  Enzymes and Stomach Acid (HCl)
• Mechanical digestion is done through chewing and peristalsis
• Where and how are proteins digested initially?

  Stomach, broken down by pepsin into amino acids, and first absorbed thorough the stomach
• Where is alcohol absorbed?

  Stomach
• Three section of the small intestine are the duodenum, jejunum, and ileum
• Where does stomach acid neutralization occur?


  Duodenum (First part of small intestine)
• What are the three salivary glands?


  Parotid, submandibular, sublingual.
• What prevent food and liquid from entering the trachea and lungs?


  Small flap of tissue called the epiglottis
• Why is it important to not have food or liquid enter the lungs?

  Prevent infections and respiratory tract obstructions leading to a difficulty to breathe
• What protects the inside lining of the stomach from the hydrochloric acid?


  Mucus layer
• What are stomach ulcers?


  Open sores that develop on the lining of the stomach when the stomach acid burns through the stomach tissue
• What is bile?


  Green/yellow liquid produced by the liver and stored in the gall bladder
• What does bile do?


  Separates large fat molecules to smaller droplets
• Does bile produce a chemical or physical change?

  Physical
• Protease/ Pepsin- Protein

  Amylase- Carbohydrates

  Lipase- Lipids
• What are the two sphincter muscles of the stomach?

  Cardiac and pyloric sphincter.
• Where does HEAVY duty digestion and most absorption take place?

  Small intestine specifically the jejunum
• Why can't pepsin further digest proteins in the small intestine?

  Pepsin only works at a PH of 2, so other protein digesting enzymes like protease finish the job
• What substance is produced by the pancreas to neutralize stomach acid in the duodenum?


  Bicarbonate
• Villi are small finger like projections which increase the surface area in the small intestine for nutrient absorption