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Understanding Macronutrients and Digestive System Function

Explore the role of macronutrients - carbohydrates, fats, proteins, and micronutrients in cellular processes. Understand the stages of food processing, enzyme function, and the anatomy of the digestive system. Learn about common digestive disorders and review key concepts in nutrition.

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Understanding Macronutrients and Digestive System Function

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  1. Digestive System

  2. Macronutrients (macromolecules): • 1. ·Carbohydrates:provide sources of glucose needed for cellular respiration (energy) • sources: breads, cereal, pasta, potatoes... • glucose stored as glycogen in liver • cellulose (plant cell wall) not a human nutrient • broken down into simple sugars

  3. Macronutrients (macromolecules): • 2. ·Fats:important in cell membrane structure, surrounds organ and joints, long term energy, hormones • sources: butter, oils, animal fat • saturated fats (bad)...solid at room temp • unsaturated fats (good) ...liquid at room temp • broken down into fatty acids

  4. Macronutrients (macromolecules): • 3. ·Proteins: provide structural support; transport proteins move molecules around body (haemoglobin); enzymes speed up chemical reactions • sources: meat, fish, eggs, milk, beans, nuts... • broken down into amino acids • 8 essential AAs...ingest

  5. Micronutrients: • Vitamins: organic compounds (CHO elements) ...A,B1,C,D,E • Minerals: inorganic compounds...Calcium, iron, potassium, sodium • Water:70% of the body...blood (plasma)=90% • - water transports soluble compounds • - cooling (sweating) • pg406#3,4,5 • Pg 410#1,5,11

  6. Enzymes break down macromolecules by hydrolysis (adding a water molecule breaks bonds between subunits

  7. 4 stages of food processing:

  8. 4 stages of food processing: • 1. Ingestion: the taking in of nutrients • 2. Digestion: the breakdown of complex organic molecules into smaller components: • Mechanical=physically breaking molecules up...teeth • Chemical=changing the chemical structure...enzymes • 3. Absorption: the taking up of digested molecules from digestive to circulatory system • 4. Egestion: the removal of waste from the body

  9. Alimentary canal: • a tube where food is processed: head --->anus • function is the same but the length varies depending on feeding habits. Why rabbit longer? • page 410#13-16

  10. 1. The Mouth • Mechanical digestion begins with the teeth physically breaking the food down (smaller to pass) • allow for a greater surface area for chemical digestion • Chemical digestion • ·Salivary glands secrete enzyme: salivary amylase • ·breaks down starch molecules (carbs-simple sugars) • ·This enzyme works best at a neutral pH. • ·Mucus and water added…moisten

  11. 2. Esophagus • muscular tube from mouth – stomach • epiglottiscloses over the trachea when you swallow • muscle contractions of the walls of the esophagus (called peristalsis) move the food (bolus) along

  12. 3. esophageal (cardiac) sphincter • provides some involuntary control of food entering or leaving the stomach

  13. 4. Stomach mechanical digestion • through the contraction of the muscles around it • folding called rugae.

  14. 4. Stomach: Chemical Digestion • Pepsin, an enzyme that breaks down proteins to AAs is added (inactive = needs low pH) • Food is “paste like” called chyme • Hydrochloric acid is added • breaks down fibrous tissue • kills bacteria • lowers the pH…activates pepsin • Is amylase still functioning?? • Mucus is also added to protect the stomach lining

  15. 5. Pyloric sphincter • Controls movement of chyme into the duodenum (small intestine)

  16. 6 Small Intestine • chyme into the duodenum through pyloric sphincter • release of secretin, a hormone to the pancreas • releases sodium bicarbonate (Na2HCO3)... increases pH of the chyme to 8 • activates most intestinal enzymes • pancreas (releases its enzymes: lipases, proteases, and carbohydrases) • gall bladder (stores/releases bile produced in liver) • Bile emulsifies fat (physical breakdown-breaks big blobs into little blobbies

  17. jejunum and ileum (SI) are primarily for absorption • finger-like projections: villiincrease the surface area for absorption of the digested nutrients • inside each villus is a capillary network for absorbing simple sugars and amino acids • central lacteal for absorbing fat particles

  18. 7. Large Intestine • water and dissolved minerals are absorbed from the undigested food • produce vitamins B and K as waste products (absorbed) • undigersted material=feces

  19. Accessory Organs: • Salivary Glands: amylase and mucus • Liver produces bile (fat breakdown...are not lipases)…detoxification (alcohol) • Gall Bladder stores bile • Pancreas produces and releases sodium bicarbonate and enzymes

  20. Digestive System Disorders Peptic ulcer Crohn's disease constipation hepatitis cirrhosis page 422#19-24 endoscopes diabetes and insulin page 427#2,3,4,6,13,15

  21. Digestive Review • Macronutrients (Carbohydrates, Proteins, fats); • Micronutrients (vitamins and minerals) • Enzymes, pH and control of enzyme activation • Ingestion, digestion, absorption, egestion • Mechanical and chemical digestion • Anatomy (mouth, pharynx, epiglottis, esophagus, cardiac sphincter, stomach, pyloric sphincter, duodenum, jejunum, ileum, caecum, colon, rectum, anus) • Accessory organs: pancreas, salivary glands, liver, gall bladder • Disorders: Peptic Ulcer, Cirrhosis, Hepatitis, Diabetes • Page 521#1-7,10,12,14,17-22,44,45,47,51,53,57,58, • Page 526#1-3,6-10

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