Internal Systems and Regulation

1. Internal Systems and Regulation Nutrients, Digestion and Nutrition

2. Organs & Organ Systems  Cells  Tissues  Organs  Organ systems  Organisms • p. 205, tab. 1

3. Monitoring Organs • X-rays  electromagnetic waves…what do they do? • Bismuth and barium • CT scan  computerized axial tomography (p. 206) • Many x-ray pictures, computer assimilated to give cross sectional views and 3D images • Gases, solids and liquids can all be identified • Nuclear imaging (p. 207) • Information about function as radioisotopes (radionuclides) collect in target organs and emit radiation which is translated into a picture • NMR  nuclear magnetic resonance technology • Structure and function of organs • NMR subcategory is MRI • Uses the spinning motions of atomic nuclei to produce a map of the internal structures of the body and how they are functioning

4. Obtaining Food • Essential Nutrients • Heterotrophs – organisms that depend on organic molecules manufactured by other living things • Autotrophs – nourish themselves using inorganic material

5. Components of Digestion • Ingestion – taking in of nutrients • Digestion – breakdown of molecules by enzymes • Absorption – transport of digested nutrients to tissues of the body • Egestion – removal of wastes

6. Digestive Enzymes • Enzymatic reactions in the body are controlled by temperature and pH • Enzyme activity peaks at 37oC • pH effects on enzymatic activity • Pepsin – low pH • Amylase – neutral pH • Trypsin – basic pH

7. Digestion Overview • Single celled organisms (p. 209, fig. 3) • Hydrolytic enzymes  use water to break down molecules • Simple multi-cellular organisms (p. 209, fig. 4) • Gastrovascular cavity – holds and digests, wastes out • Complex multi-cellular organisms (p. 209, fig. 5) • Alimentary canal  specialized regions • Pharynx  esophagus  stomach (crop)  (gizzard)  intestine {hydrolytic enzymes & transportation of nutrients}  anus • Humans ~ 6.5 to 9m in length

8. Ingestion • Mouth – chemical and mechanical digestion • Teeth • 3 molars, 2 premolars, 1 canine, 2 incisors on each side (4 total) of the top and bottom • Tooth – has root and crown • Enamel crown has Ca2+ compounds and is the hardest substance in the body • Dentin inside the enamel and it has pulp (nerves and blood vessels) • Decay??? • Tongue (p. 211, fig. 2) • Papillae – contain the taste buds (sweet, sour, bitter, salty) • Uvula – prevents food from entering the pharynx • Saliva • 3 pairs of salivary glands which secrete saliva using ducts • Parotid glands are the largest, sublingual are the smallest and the third set are the submaxillary glands

9. Ingestion • Esophagus • Need to ensure trachea closes and that food passes into the esophagus • Epiglottis covers the glottis so this does not happen • Circular and longitudinal muscles (24 cm) • Bolus of food is moved along using peristalsis • Wavelike, muscular contractions and relaxations • Circular muscles over food relax while longitudinal in front of food contract • Circular muscles behind food contract while the longitudinal muscles relax • p. 212, fig. 4 • Mucin helps to move food along • Regurgitation – movement of food back up to mouth

10. The Digestive Tract • Stomach • Muscular, J-shaped organ whose lining is covered with gastric glands • Glands secrete gastric juice • Has 3 layers of muscle (not just the 2 in the esophagus) – circular, longitudinal and oblique • All 3 layers work to break up food in the presence of gastric juices (mucus, HCl, pepsin) to form chyme • Mucus  protective layer • HCl kills harmful substances and converts pepsinogen to pepsin • Pepsin  protein digesting enzyme • Pyloric sphincter – controls movement of food from stomach to small intestine. • Ulcers  H. pylori bacteria • Endoscope and laser treatment

11. The Digestive Tract • Small Intestine • Named due to small diameter (2.5 cm) not length (7m) • Large intestine  diameter (7.6cm), length (1.5m) • Permanent folds to increase surface area (p. 225, fig. 2) • On these folds are villi which further increases the surface area and secrete intestinal juices • Also lacteal or lymph vessels in the villi which accept larger fat particles • Duodenum – U-shaped and is the shortest yet widest of the 3 sections • It lacks oblique muscles • Pancreatic and bile ducts empty into this section

12. The Digestive Tract • Jejunum – 2.5m long • Contains more folds then the duodenum • Breaks down remaining proteins and carbohydrates • Ileum – 3m long • Fewer and smaller villi • Continue digestion and move food into the large intestine • Pancreas • Acid causes prosecretin to be converted to secretin which travels to the pancreas and causes bicarbonate ions to be released • pH from 2.5 to 9 which inactivates pepsin • Source of enzymes that act on carbohydrates (amylase), fats (lipases), and peptides (trypsinogen). • p. 218, table 1

13. Related Organ • Liver • Digestive role of producing bile salts from cholesterol • Bile breaks down fats and is stored in the gall bladder • Released into small intestine and break up fat globules into droplets • Allows for faster processing and absorption into bloodstream • Demolitions expert – red blood cells • Storage of monosaccharides (glucose  glycogen) and vitamins • Protein breakdown – elimination or conversion, converts toxic N groups to urea • Detoxification – breaks down ingested poisons

14. The Digestive Tract • Large Intestine – 1.5m, diameter is greater though • Caecum, colon, rectum and anal canal • Caecum – blind end which leads to the appendix • Colon – water and dissolved minerals are absorbed and bacteria break down what is left • Rectum – accepts feces and passes it along to the anal canal (last 20 cm of large intestine) • Anus – feces pass out of body • Anal sphincters help to control

15. How long does it take to digest food? Overall 24 to 72 hours depending on food and metabolic rate Gum – is not digestible so it will pass through your digestive system the same as any other non digestible item (i.e. coins, marbles).

16. How to improve your digestion • Tip #1: Cover the Basics • Basic 1: Chew, Chew, Chew Take smaller bites. • Put your fork down in between bites. • Try using chopsticks - it forces you to slow down. • Thoroughly chew each bite of food. • Carbohydrate digestion begins in the mouth - chewing grains thoroughly allows amylase, the digestive enzyme present in saliva, to digest the grains.

17. How to improve your digestion Basic 2: Get Enough WaterInsufficient water intake is a primary cause of constipation. Constipation then causes an imbalance in bacteria, promotes inflammation of the intestinal lining, and can even lead to the absorption of larger molecules, a condition known as intestinal permeability.

18. How to improve your digestion • Basic 3: Increase Your Dietary Fiber • Good sources of dietary fiber include: Dried fruit, such as dates, figs, and prunes • Beans and legumes- if you don't have time to cook dried beans, buy canned, but make sure you rinse them thoroughly before cooking. Lentils and split peas are less gas-forming than other legumes. • Bring an apple with you to work as a snack • Ground flaxseeds are a gentle laxative. They can be useful for chronic constipation, damage to the intestine wall from laxative use, irritable bowel, and to soothe inflammation. Sprinkle ground flaxseeds on rice, grains, salads, or any other meal of your choice.

19. How to improve your digestion • Tip #2: Practice Mindful Eating • A pilot study at Indiana State University found that mindfulness, including specific instructions to slowly savor the flavor of food and be aware of how much food is enough, helped to reduce eating binges from an average of four binges per week to one and a half. Eat in the moment. Savor every bite, enjoying the flavors, textures, and smells of your meal. • Buy fresh flowers to put on the dining table. • Use smaller cutlery so that you eat less with each bite. • Create a beautiful atmosphere - dim the lights, play music and light candles.

20. How to improve your digestion Tip #3: Address Food Sensitivities and Allergies Food sensitivities are behind many digestive disorders. For example, between 33% and 66% of IBS patients report having one or more food intolerances, resulting in bloating, gas, and pain. The most common culprits are milk and dairy (40-44%) and grains (40-60%). A trained practitioner can supervise an elimination diet. Many foods are removed from the diet for a brief period of time, then re-introduced sequentially to isolate the body's reaction to the offending foods.

21. How to improve your digestion • Tip #4: Increase Good Gut Bacteria • Not all bacteria is bad. There are over 400 different kinds of bacteria and yeasts in the digestive system. Of these, the bacteria Lactobacillus acidophillus and Bifidobacteriumbifidum are considered good "probiotic" bacteria because they can help to maintain intestinal health. • Although good bacteria can be found in some yogurt, there is a wide variation in the quantity and quality. Look for good quality organic yogurt that add the active cultures after pasteurization, because this heat process destroys both good and bad bacteria. • Supplements containing acidophilus and bifidobacteria can be found in health food stores. They are especially helpful for the following conditions: Irritable bowel syndrome • Diarrhea • Gas, bloating, flatulence • Recurring vaginal yeast infections • Bad breath

22. Regulation of Secretions • Nerves and hormones are in charge • Hormone = chemical regulator that is secreted in one part of the body and transported to another part, where it causes a response. • e.g. digestive glands on walls of stomach are stimulated by nerves and by gastrin. In response, individual glands secrete mucin, pepsin, HCl and lipases. • Further, chyme in duodenum stimulates ductless glands in the walls of the duodenum to secrete hormone secretin. • Secretin goes to the pancreas to stimulate duct cells there to release alkaline fluid (sodium bicarbonate)

23. Knowledge is Power • How do we know what we know? • William Beaumont (1833) took a patient who had been shot in the stomach. • Improperly healed into a fistula • Foods was put in with a string attached • Emotions linked to secretions

24. Homeostasis • Perfect internal situation • 37oC, 0.1% blood sugar, pH of 7.35 • How do we maintain this? • Sensors  coordinating centre (?)  regulator • Meal blood sugar increases  pancreas releases insulin  insulin allows sugar to be absorbed by cells  in liver, glycogen in formed • Homeostasis and Digestion • Seeing, smelling and tasting produce gastric secretions • Secretin released when food travels from stomach to small intestine • Speed of food movement • Large meal will cause receptors increase muscle movement of stomach to move food out of stomach • Fatty meal will be identified and cause food to stay in small intestine longer

25. Food Energy • Using energy all the time • Joules (J) or kilojoules (kJ) compared to calories • 1 cal = 4.18 J • BMR  basal metabolic rate • p. 230, table 1 • Metabolic Factors • Metabolism is the sum of all the chemical reactions that occur within body cells • Differences? • Energy uses (p.232, table 2) • Dieting Dangers

26. Nutrients • Amino acids - there are 20, we can not make 10 • Fats • Get a bad name but we need them to help us absorb vitamins, insulate, protect delicate organs, protect nerves, cell membrane • Vitamins – organic molecules that help change food into energy • Water soluble – can not be stored • C and B groups • Fat soluble – can be stored • A, D, E, K • Minerals – elements that help change food into energy • Ca, I, Fe, P, K, Na • Antioxidants reduce the danger of oxygen free radicals • FR – created by exposure to sunlight, Xrays, ozone, tobacco smoke, etc. • Damage to genetic information

27. Digestive Disorders • Symptoms • Bleeding • Bloating • Constipation • Diarrhea • Heartburn • Incontinence • Nausea and vomiting • Pain in the belly • Swallowing problems • Weight gain or loss