gastro & metabolic system

• What is the primary function of homeostasis in the body?


  To ensure food is digested and absorbed for adequate nutrient supply.
• How does homeostasis contribute to the immune system?


  It provides protection through lymphoid tissue in the digestive tract, which comprises 70% of the body's immune system.
• What are the 5 key activities of the digestive system?


  • Ingestion
  • Propulsion
  • Digestion
  • Absorption
  • Elimination
• What is the structure of the digestive tract?


  It is a tubular structure that runs from the mouth to the anus.
• What is the role of enzymes in the digestive tract?


  Enzymes are secreted to chemically digest the nutrients.
• Why is the digestive tract highly vascular?


  To enable the absorption of nutrients.
• What are the four layers of the tubular structure of the digestive tract?


  • Mucosa
  • Submucosa
  • Muscular
  • Serosa
• Where can you find more details about the layers of the digestive tract?

  In Chapter 8 The Digestive System, pages 217-219.
• What are the functions of the tongue in digestion?


  • Manipulates food into position for mastication
  • Aids in swallowing
• What are the roles of teeth and saliva in digestion?


  • Teeth: Mastication
  • Saliva: Digestion and lubrication
• How does swallowing initiate the swallowing reflex?


  Sensory fibers in the oropharynx respond to stimuli to initiate the reflex.
• What is the function of the oesophagus?


  To move food to the stomach by peristalsis.
• What is the length of the oesophagus?


  18-25 cm.
• What controls the entry of food into the stomach?


  The cardiac sphincter muscle.
• What are the two types of digestion that occur in the stomach?


  Chemical and mechanical digestion.
• What are the three phases of gastric acid production?


  • Cephalic
  • Gastric
  • Intestinal
• What are the six classes of nutrients?


  • Water
  • Proteins
  • Carbohydrates
  • Fats
  • Minerals
  • Vitamins
• What percentage of the diet should come from carbohydrates?


  40-45%.
• What is the primary use of carbohydrates in the body?


  As a source of energy.
• What are the four main types of carbohydrates?


  • Monosaccharides
  • Disaccharides
  • Oligosaccharides
  • Polysaccharides
• What is the daily protein requirement for adults?


  70-100 g.
• What are proteins made up of?


  Amino acids.
• When is protein used for energy?


  When there are no carbohydrates or fats available.
• What do fats (lipids) provide in terms of energy?


  They provide twice the amount of energy as carbohydrates.
• What are the three main types of fat?


  • Triglycerides
  • Phospholipids
  • Lipoproteins
• What are the four classifications of lipoproteins?


  • Chylomicrons
  • High-Density Lipoproteins (HDLs)
  • Low-Density Lipoproteins (LDLs)
  • Very Low-Density Lipoproteins (VLDLs)
• What is the difference between water-soluble and fat-soluble vitamins?


  • Water-soluble: Readily absorbed, excess excreted in urine.
  • Fat-soluble: Absorption depends on fat, stored in the body.
• What are the functions of minerals and trace elements in the body?


  • Structure
  • Fluid balance
  • Nervous and muscular activity
  • Blood clotting
• What are the three parts of the small intestine?


  The duodenum, jejunum, and ileum.
• What happens to gastric juices in the small intestine?


  They are neutralized and stimulate the pancreas to secrete and the gall bladder and liver to release bile.
• What is the final digestion process in the small intestine?


  Proteins are broken down to amino acids and carbohydrates into glucose by brush border enzymes.
• How are nutrients absorbed in the small intestine?


  Nutrients (except lipids) are absorbed and carried to the liver, while lipids are drained into the lymph vessels.
• What is the primary function of the large intestine?


  To absorb water and electrolytes and eliminate waste.