Study Guide Human Biology Digestive System PDF

⭐⭐ ⭐ ⭐ Study Guide: Human Biology (Digestive System) 1. Locate, Identify and Give a Function for Each of the Following: Mouth (oral cavity) Function: Entry point for food, mechanical digestion through chewing, and chemical digestion via saliva. Tongue Funct...

⭐⭐ ⭐ ⭐ Study Guide: Human Biology (Digestive System) 1. Locate, Identify and Give a Function for Each of the Following: Mouth (oral cavity) Function: Entry point for food, mechanical digestion through chewing, and chemical digestion via saliva. Tongue Function: Assists in food manipulation and swallowing; contains taste buds Teeth Function: Mechanical digestion by breaking down food into smaller pieces. Salivary Glands Function: Produce saliva, which contains enzymes (amylase) that begin the digestion of carbohydrates. Pharynx Function: Passageway for food and air; participates in swallowing. Epiglottis Function: Prevents food from entering the trachea during swallowing. Esophagus Function: Transports food from the pharynx to the stomach through peristalsis. Cardiac Sphincter Function: Controls the opening between the esophagus and the stomach; prevents backflow of stomach contents. Stomach Function: Mechanical and chemical digestion of food; secretes acid and digestive enzymes. Pyloric Sphincter  Function: Regulates the passage of chyme from the stomach to the duodenum. Duodenum Function: First part of the small intestine; major site of chemical digestion and absorption. Liver Function: Produces bile, detoxifies substances, processes nutrients. Gall Bladder Function: Stores and concentrates bile produced by the liver. Pancreas Function: Produces digestive enzymes and bicarbonate; regulates blood sugar by producing insulin and glucagon. Small Intestine Function: Digestion and absorption of nutrients. Appendix Function: No significant digestive function; may have immune functions. Large Intestine (Colon) Function: Absorbs water and electrolytes; forms and stores feces. Rectum Function: Stores feces until defecation. Anus Function: Controls the expulsion of feces. 2. Digestive Enzymes and Their Functions: Salivary and Pancreatic Amylase Source: Salivary glands, pancreas Function: Breaks down starches into sugars. Proteases (Pepsin, Trypsin) Source: Stomach (pepsin), pancreas (trypsin) Function: Break down proteins into peptides and amino acids. Lipase Source: Pancreas Function: Breaks down fats into fatty acids and glycerol. Peptidase, Nucleosidase Source: Small intestine Function: Breaks down peptides into amino acids; breaks down nucleotides into nucleosides. Nuclease Source: Pancreas Function: Breaks down nucleic acids into nucleotides. 3. Describe Swallowing and Peristalsis: Swallowing Process: Involves voluntary action (tongue pushes food to pharynx) and involuntary action (reflex action by pharynx and esophagus to move food to stomach). Peristalsis Function: Rhythmic contractions of the muscles in the esophagus and intestines to move food through the digestive tract. 4. Digestive Actions of Gastric, Pancreatic, and Intestinal Juices: Gastric Juices Components: Hydrochloric acid (HCl), pepsinogen (activated to pepsin) Function: Breaks down proteins, kills bacteria, provides acidic pH for enzyme activity. Pancreatic Juices  Components: Enzymes (amylase, lipase, proteases), bicarbonate Function: Neutralizes stomach acid, digests carbohydrates, fats, and proteins. Intestinal Juices Components: Various enzymes (maltase, lactase, sucrase, peptidases) Function: Final breakdown of food molecules for absorption. 5. Insulin and Glucagon: Source: Pancreas Function of Insulin: Lowers blood glucose levels by facilitating cellular uptake of glucose. Function of Glucagon: Raises blood glucose levels by stimulating the release of glucose from liver stores. 6. Role of Bile and Hormones in Digestion: Bile Function: Emulsifies fats, increasing surface area for lipase action. Hormones (CCK, Secretin, Somatostatin, Gastrin) CCK: Stimulates bile release from gall bladder and pancreatic enzyme secretion. Secretin: Stimulates bicarbonate secretion from pancreas. Somatostatin: Inhibits gastric secretion. Gastrin: Stimulates gastric acid secretion. 7. Six Major Functions of the Liver: 1. Bile production. 2. Detoxification of blood. 3. Storage of glycogen, vitamins, and minerals. 4. Synthesis of plasma proteins. 5. Metabolism of carbohydrates, fats, and proteins. 6. Conversion of ammonia to urea. 8. Structure and Function of the Small Intestine: Structure: Sections: Duodenum, jejunum, ileum Features: Villi and microvilli increase surface area for absorption. Function: Digestion and absorption of nutrients. 9. Defecation Reflex: Process: Triggered by the stretching of the rectum. Involves relaxation of the internal anal sphincter and voluntary relaxation of the external anal sphincter. 10. Functions of E. coli in the Colon: Functions: Produces vitamin K and B- complex vitamins. Ferments undigested carbohydrates. Competes with harmful bacteria, preventing infections. Q1: What is the function of the mouth (oral cavity) in the digestive system? A1: Entry point for food, mechanical digestion through chewing, and chemical digestion via saliva. Q2: What role does the tongue play in digestion? A2: Assists in food manipulation and swallowing; contains taste buds. Q3: How do teeth contribute to digestion?  A3: Mechanical digestion by breaking down food into smaller pieces. Q4: What is the function of the salivary glands? A4: Produce saliva, which contains enzymes (amylase) that begin the digestion of carbohydrates. Q5: Describe the function of the pharynx. A5: Passageway for food and air; participates in swallowing. Q6: What is the role of the epiglottis in the digestive system? A6: Prevents food from entering the trachea during swallowing. Q7: How does the esophagus aid in digestion? A7: Transports food from the pharynx to the stomach through peristalsis. Q8: What does the cardiac sphincter do? A8: Controls the opening between the esophagus and the stomach; prevents backflow of stomach contents. Q9: What are the primary functions of the stomach? A9: Mechanical and chemical digestion of food; secretes acid and digestive enzymes. Q10: What is the function of the pyloric sphincter? A10: Regulates the passage of chyme from the stomach to the duodenum. Q11: Describe the role of the duodenum in digestion. A11: First part of the small intestine; major site of chemical digestion and absorption. Q12: What functions does the liver perform in digestion? A12: Produces bile, detoxifies substances, processes nutrients. Q13: What is the purpose of the gall bladder? A13: Stores and concentrates bile produced by the liver. Q14: How does the pancreas contribute to the digestive system? A14: Produces digestive enzymes and bicarbonate; regulates blood sugar by producing insulin and glucagon. Q15: What is the main function of the small intestine? A15: Digestion and absorption of nutrients. Q16: What is the appendix’s role in the digestive system? A16: No significant digestive function; may have immune functions. Q17: Describe the functions of the large intestine (colon). A17: Absorbs water and electrolytes; forms and stores feces. Q18: What is the function of the rectum? A18: Stores feces until defecation. Q19: How does the anus contribute to the digestive process? A19: Controls the expulsion of feces. Q20: What is the function of salivary and pancreatic amylase? A20: Breaks down starches into sugars. Q21: What do proteases (pepsin, trypsin) do? A21: Break down proteins into peptides and amino acids. Q22: How does lipase function in digestion? A22: Breaks down fats into fatty acids and glycerol. Q23: What is the role of peptidase and nucleosidase? A23: Breaks down peptides into amino acids; breaks down nucleotides into nucleosides. Q24: What does nuclease do? A24: Breaks down nucleic acids into nucleotides. Q25: Describe the process of swallowing. A25: Involves voluntary action (tongue pushes food to pharynx) and involuntary action (reflex action by pharynx and esophagus to move food to stomach). Q26: What is peristalsis? A26: Rhythmic contractions of the muscles in the esophagus and intestines to move food through the digestive tract. Q27: What are the components of gastric juices and their functions? A27: Hydrochloric acid (HCl) and pepsinogen (activated to pepsin); they break down proteins, kill bacteria, and provide acidic pH for enzyme activity. Q28: What are the components and functions of pancreatic juices? A28: Enzymes (amylase, lipase, proteases) and bicarbonate; neutralize stomach acid and digest carbohydrates, fats, and proteins. Q29: What are the components and functions of intestinal juices? A29: Various enzymes (maltase, lactase, sucrase, peptidases); final breakdown of food molecules for absorption. Q30: What is the function of insulin and its source? **A30 Q30: What is the function of insulin and its source? A30: Produced by the pancreas; insulin lowers blood glucose levels by facilitating cellular uptake of glucose. Q31: What is the function of glucagon and its source? A31: Produced by the pancreas; glucagon raises blood glucose levels by stimulating the release of glucose from liver stores. Q32: What is the role of bile in digestion? A32: Emulsifies fats, increasing the surface area for lipase action. Q33: Describe the functions of the hormone CCK in digestion. A33: Cholecystokinin (CCK) stimulates the release of bile from the gall bladder and pancreatic enzyme secretion. Q34: What is the function of the hormone Secretin? A34: Secretin stimulates the secretion of bicarbonate from the pancreas to neutralize stomach acid. Q35: How does the hormone Somatostatin affect digestion? A35: Somatostatin inhibits the secretion of gastric acid and slows down digestive processes. Q36: What is the role of the hormone Gastrin? A36: Gastrin stimulates the secretion of gastric acid in the stomach. Q37: List six major functions of the liver. A37: 1. Bile production. 2. Detoxification of blood. 3. Storage of glycogen, vitamins, and minerals. 4. Synthesis of plasma proteins. 5. Metabolism of carbohydrates, fats, and proteins. 6. Conversion of ammonia to urea. Q38: Describe the structure of the small intestine and its specialization for digestion and absorption. A38: The small intestine has three sections: duodenum, jejunum, and ileum. It features villi and microvilli that increase surface area for nutrient absorption. Q39: What is the defecation reflex and how does it work? A39: The defecation reflex is triggered by the stretching of the rectum, leading to the relaxation of the internal anal sphincter and voluntary relaxation of the external anal sphincter to expel feces. Q40: What are the functions of E. coli in the colon? A40: E. coli in the colon produces vitamin K and B-complex vitamins, ferments undigested carbohydrates, and competes with harmful bacteria to prevent infections. Q41: What is the primary function of hydrochloric acid (HCl) in the stomach? A41: Hydrochloric acid (HCl) helps break down food, activates pepsinogen into pepsin, and kills bacteria. Q42: What is the role of mucus in the stomach? A42: Mucus protects the stomach lining from the harsh acidic environment and digestive enzymes. Q43: How does the structure of the villi in the small intestine aid in absorption? A43: Villi, with their finger-like projections, increase the surface area for absorption and contain blood vessels and lacteals to transport absorbed nutrients. Q44: What is the difference between mechanical and chemical digestion? A44: Mechanical digestion involves the physical breakdown of food (e.g., chewing, churning), while chemical digestion involves enzymatic breakdown of food into smaller molecules. Q45: What is chyme and where is it formed? A45: Chyme is the semi-liquid mass of partially digested food mixed with digestive juices, formed in the stomach. Q46: What is the function of the hormone ghrelin? A46: Ghrelin is produced by the stomach and signals hunger to the brain, stimulating appetite. Q47: What are micelles and their role in fat digestion? A47: Micelles are small transport carriers in the intestines that enable the absorption of fatty acids and monoglycerides. Q48: How does the large intestine contribute to the formation of feces? A48: The large intestine absorbs water and electrolytes from the remaining indigestible food matter, compacting it into feces. Q49: What triggers the release of bile from the gall bladder? A49: The hormone cholecystokinin (CCK) triggers the release of bile from the gall bladder into the duodenum. Q50: What is the role of bicarbonate in pancreatic juice? A50: Bicarbonate neutralizes the acidic chyme entering the duodenum from the stomach, creating an optimal pH for digestive enzyme activity. Q51: What is the significance of the hepatic portal vein? A51: The hepatic portal vein transports nutrient-rich blood from the digestive organs to the liver for processing and detoxification. Q52: Describe the process of emulsification in fat digestion. A52: Emulsification is the process where bile salts break down large fat globules into smaller droplets, increasing the surface area for the action of lipase. Q53: What are brush border enzymes and where are they found? A53: Brush border enzymes are found on the microvilli of the small intestine and aid in the final stages of digestion of carbohydrates and proteins. Q54: How does the nervous system regulate digestive processes? A54: The enteric nervous system, along with the autonomic nervous system, regulates digestive processes through reflexes that control muscle contractions and secretions. Q55: What is the role of the hormone motilin? A55: Motilin stimulates migrating motor complexes (MMCs) in the small intestine, promoting peristalsis and clearing out the gut between meals. Q56: How does the body prevent autodigestion of the pancreas? A56: The pancreas produces inactive enzyme precursors (zymogens) that are activated only in the small intestine to prevent autodigestion. Q57: What are the primary components of feces? A57: Feces primarily consist of water, bacteria, undigested food residues, sloughed-off intestinal cells, and waste products. Q58: Describe the role of gut microbiota in digestion. A58: Gut microbiota help break down certain indigestible carbohydrates, synthesize vitamins, and protect against pathogenic bacteria. Q59: What is the function of gastrin- releasing peptide (GRP)? A59: Gastrin-releasing peptide (GRP) stimulates the release of gastrin from G-cells in the stomach, promoting acid secretion. Q60: Explain the process of nutrient absorption in the small intestine. A60: Nutrient absorption in the small intestine involves active transport and diffusion through the enterocytes of the villi into the bloodstream or lymphatic system. Q61: What triggers the release of digestive enzymes from the pancreas? A61: The hormone cholecystokinin (CCK) triggers the release of digestive enzymes from the pancreas. Q62: How is chyme neutralized when it enters the small intestine? A62: Bicarbonate from the pancreas neutralizes the acidic chyme when it enters the duodenum. Q63: What is the enteric nervous system and its role in digestion? A63: The enteric nervous system, also known as the “second brain,” regulates the functions of the gastrointestinal tract, including peristalsis and enzyme secretion. Q64: What are Peyer’s patches and their function? A64: Peyer’s patches are lymphoid tissues in the small intestine that monitor intestinal bacteria and prevent the growth of pathogenic bacteria. Q65: Explain the function of lacteals in the small intestine. A65: Lacteals are lymphatic vessels in the villi of the small intestine that absorb dietary fats and transport them to the bloodstream. Q66: How does the structure of the stomach protect it from self- digestion? A66: The stomach is protected by a thick layer of mucus that lines its walls, preventing the acidic gastric juices from damaging the tissue. Q67: What role does the hormone motilin play in the digestive system? A67: Motilin stimulates the migrating motor complex (MMC) which sweeps residual undigested material through the digestive tract between meals. Q68: Describe the cephalic phase of digestion. A68: The cephalic phase is the early phase of digestion stimulated by the sight, smell, taste, or thought of food, triggering gastric secretions in preparation for eating. Q69: How does the stomach contribute to the regulation of hunger and satiety? A69: The stomach produces ghrelin, which signals hunger to the brain, and cholecystokinin (CCK), which contributes to the feeling of satiety. Q70: What is the significance of the ileocecal valve? A70: The ileocecal valve controls the flow of chyme from the small intestine into the large intestine and prevents backflow. Summary of Key Points 1. Basic Anatomy and Functions: Mouth, tongue, teeth, salivary glands, pharynx, esophagus, stomach, small and large intestines, rectum, anus, liver, gall bladder, pancreas. 2. Enzymes and Secretions: Salivary amylase, pancreatic amylase, proteases (pepsin, trypsin), lipase, nucleases, bicarbonate, bile. 3. Digestive Processes: Mechanical and chemical digestion, swallowing, peristalsis, emulsification. 4. Hormonal Regulation: Insulin, glucagon, gastrin, secretin, CCK, somatostatin. 5. Absorption and Transport: Villi and microvilli, hepatic portal vein. 6. Microbiota and Miscellaneous: Gut microbiota functions, defecation reflex, roles of E. coli, etc. Ch 9 Assignment Digestive System 9.1 The Digestive Tract (pp266-271) 1. What two types of digestion exist in the digestive system? Describe them. The two types of digestion are mechanical digestion and chemical digestion. Mechanical digestion is when food is physically broken down through chewing in the mouth and churning and mixing in the stomach. Chemical digestion is when many different enzymes break down the macromolecules in food to small absorbable organic molecules. 2. What are the results of digestion? After digestion carbohydrates are broken down into monosaccharides, fats are broken down into fatty acids, and proteins are broken down into amino acids. Nucleic Acids break down into nucleotides. After those have been extracted, then indigestible wastes remain. 3.What type of proteins help break down macromolecules? Enzymes help break down macromolecules. 4. Describe the following parts of the human digestive tract; mouth (with salivary glands), pharynx and esophagus The mouth is bounded externally by the lips and cheeks. The mouth contains components such as the tongue, tonsils, and salivary glands. The tongue is a muscle that has taste buds, allowing us to taste our food. The tonsils are in the back of the mouth on either side of the tongue. Tonsils contain lymphoid tissue that helps protect the body against infections. There are also three pairs of salivary glands that secrete saliva. Saliva keeps the mouth most and contains salivary amylase, an enzyme that digests starch. The pharynx is the area that receives air form the nasal cavities and food from the mouth. The esophagus is a muscular tube that goes from the pharynx all the way to the stomach. The esophagus is usually collapsed, and only opens when we swallow food. 5. Name the steps in swallowing. After the food is chewed up into a bolus, it passes from the mouth to the pharynx. The soft palate then closes to prevent food from going into the nose. At the same time, the epiglottis covers the glottis, forcing the bolus to go down the esophagus and to the stomach. 6. Define peristalsis. Peristalsis describes the rhythmic muscular contractions in the main digestion tube that occur behind the bolus and hence, push food along the digestive tract. 7. What is the difference between heartburn, GERD, and vomiting? Heartburn is a burning pain that starts in the stomach and rises to the throat. This sensation is caused by some acidic stomach contents escaping into the esophagus. This is called acid reflux. Gastroesophageal reflux disease (GERD) is a more serious form of heartburn that happens more frequently than regular heartburn. Vomiting is when the stomach contents are ejected out of the body through the mouth. 8. Describe the stomach in detail by including the following: rugae, gastric pits, gastric glands, gastric juice, pepsinogen, HCl, mucus, three layers of muscles, chyme Rugae are folds in the stomach that expand and disappear when the stomach is at full capacity. These folds increase the volume of the stomach. Gastric pits are small canals that line the surface of the epithelium. These pits contain gastric glands that produce gastric juice. Gastric juice contains pepsinogen, hydrochloric acid and mucus. Pepsinogen is a precursor enzyme to pepsin, an enzyme that breaks down proteins when exposed to hydrochloric acid. Mucus lines the stomach epithelium in order to protect it from the low pH of the stomach contents. The stomach contains three layers of muscles, longitudinal, circular, and oblique. These muscle layers aid in physical digestion by contracting and churning the food inside. After food is finished being digested by the stomach, it becomes a thick, soupy liquid called chyme. 9. What are sphincters? Sphincters are circular muscles that control passage through certain parts of the body. 10. Name the 3 parts of the small intestine? Three parts of the small intestine are the duodenum, jejunum, ileum. 11. What substances enter the duodenum? Chyme from the stomach, bile from the liver, and pancreatic juice from the pancreas enter the duodenum. 12. What does the ileum have that helps to fight infections? The ileum contains areas of lymphoid tissues called Peyer’s patches. These lymphoid tissues help create immune responses to intestinal pathogens. 13. Draw villi from Fig 9.4. Make sure to include the microvilli, lacteal and blood capillaries. 14. What is the function of a lacteal? Lacteal is a lymphatic capillary that absorbs fats in the small intestine. 15. How are sugars and amino acids taken from the small intestine to your body cells? Sugars and amino acids are absorbed by the capillaries of the villi in the small intestine. These nutrients then enter the bloodstream and are carried throughout the body. 16. Draw and label Fig 9.5, name the 3 hormones (messengers) that regulate the digestive system and explain what they do. Secretin is produced by the duodenal wall and stimulates digestive juice secretion by the liver and pancreas. CCK is produced by the duodenal wall and stimulates the pancreas to secrete digestive juices and the gall bladder to release bile. Gastrin is produced by the lower part of the stomach and enters the bloodstream. In the bloodstream, it then stimulates the stomach to produce more digestive juices. 17. What are the four parts of the large intestine and what are its main functions? The cecum is a small pouch that is located between the junction where the small and large intestine meet. The cecum has a vestigial organ called the appendix, or vermiform appendix. The colon has three sections. The ascending colon goes up the right side of the body and levels off at the liver. It then turns into the transverse colon that crosses the abdominal cavity below the liver and stomach. The transverse colon then turns and passes down the left side of the body. This last section is called the descending colon. The rectum is the final 20cm of the large intestine. Feces are stored in the rectum before they are expelled. The anus is the sphincter at the end of the large intestine where feces are expelled. The sphincter stays contracted in order to keep feces inside the rectum. 18. What is the vermiform appendix and what role does it play? What can happen if it becomes infected? The vermiform appendix is believed to play a role in fighting infection. If the vermiform appendix becomes infected, it may become inflamed, a condition called appendicitis. If appendicitis is untreated, the appendix will burst, releasing bacteria into the peritoneal cavity. This would lead to peritonitis, the inflammation of the lining of the abdominal cavity. 19. Feces include the undigested remains of our food. Explain the details of the defecation reflex that eliminates the feces. What are the other components of feces? When feces are forced into the rectum by peristalsis, a defecation reflex occurs. First, the stretching of the rectal wall sends nerve impulses to the spinal cord. After this, the rectal muscles contract and the anal sphincters relax. This causes the feces to leave the body. 40 to 50 percent of fecal mass is made of bacteria and microbes. There are about 100 billion bacteria per gram of feces. Feces are usually three quarters water, and one quarter solids. They also contain waste products and undigested food. 20. What is the role of bacteria in the large intestine? Bacteria in the large intestine help break down indigestible materials such as cellulose. These bacteria also produce vitamins for our bodies. 9.2 Accessory Organs of Digestion (pp271-273) 1. Accessory organs help with digesting but are to part of the main digestive tract. What are three accessory organs? The three accessory organs are the pancreas, the gall bladder, and the liver. 2. Describe the exocrine function of the pancreas. The exocrine function of the pancreas is to produce pancreatic juice that contains sodium bicarbonate to help neutralize the acidic stomach acid in the chyme. Pancreatic juice is secreted from pancreatic cells. 3. The pancreas secretes endocrine hormones that keep the blood sugar levels within normal limits. What are the hormones that the pancreas secretes? Describe how they function. The pancreas secretes four endocrine hormones to regulate blood sugar levels. Insulin is secreted when blood sugar level is high, and usually occurs after eating. Insulin causes cells to take in glucose to lower blood sugar levels. Glucagon is secreted before eating when blood sugar levels are low. Glucagon mainly targets the liver and adipose tissue, causing them to break down their glycogen storage. Somatostatin is a growth inhibiting hormone that inhibits the release of growth hormone as well as stop the release of other digestive hormones. In general, somatostatin decreases the absorption of nutrients. Although CCK is not produced by the hormone, it is also related to the pancreas. CCK is a hormone produced by the duodenal wall that causes the pancreas to secrete its digestive juices. 4. The liver is the largest gland in the body. Describe its structure. The liver is a lobular organ that contains approximately 100 000 lobules that are both structural and functional units. Between the lobules are a bile duct that transports bile away from the liver, a branch of the hepatic artery that oxygenates the liver, and a branch of the hepatic portal vein that transports nutrients from the intestines. 5. State 7 functions of the liver. 1. Detoxifies blood by removing and breaking down poisonous substances. 2. Stores iron (Fe2+) and vitamins A, D, E, K, and B12. 3. Makes many plasma proteins such as albumins and fibrinogen using amino acids. 4. Store glucose in the form of glycogen, and breaks down glycogen into glucose to maintain blood glucose levels in between meals. 5. Produces urea after breaking down amino acids. 6. Removes bilirubin, a breakdown product of hemoglobin, from the blood and excretes it in bile. 7. Helps regulate blood cholesterol level by converting some cholesterol to bile salts. 6. What is bile? Where is it stored after it is made in the liver? What do bile salts do? Bile is a yellowish-green digestive fluid that is produced in the liver. It is stored in gall bladder, a muscular sac attached to the surface of the liver. Bile salts are derived from cholesterol and are present in bile. These salts allow bile to emulsify fats into many droplets, increasing the surface area of the lipids. A larger surface area means that more lipids can be broken down at a time. 9.3 Digestive Enzymes (pp273-275) 1. a) Digestive enzymes speed up specific chemical reactions that help to break down carbohydrate, proteins, and fats. Copy table 9.3 (Major Digestive Enzymes) from p 273 but look for patterns and colour code things that are the same in the same colour. (For example, anytime that it says “Small intestine” you write it in blue.) b) Fill in the missing elements in the enzyme chart below: Where does it act? Enzyme Where is it produced? What is its optimal pH type Equation of the breakdown of the polymers Lipase Pancreas Small intestine Basic Fat droplet + H2O → glycerol + fatty acids Pepsin Gastric glands Stomach Acidic Protein + H2O → peptides Pancreatic amylase Pancreas Small intestine Basic Starch + H2O → maltose Nucleosidases Small intestine Small intestine Basic Nucleotide + H2O → base + sugar + phosphate Peptidases Small intestine Small intestine Basic Peptides+ H2O → amino acids Salivary amylase Salivary glands Mouth Starch + H2O → maltose Maltose Small intestine Small intestine Basic Maltose + H2O → glucose + glucose Trypsin Pancreas Small Intestine Basic Protein + H2O → peptides Nuclease Pancreas Small Intestine Basic RNA and DNA + H2O → nucleotides 2. How is pepsin created and what does it do? Pepsin is created from the precursor pepsinogen. Pepsinogen is produced by the gastric glands in the stomach. When it comes in contact with hydrochloric acid, it turns into pepsin, an enzyme that breaks proteins down into peptides. 3. Draw, colour and label Fig 9.11 on page 274 4. a) What happens if there is an absence of any one of the digestive enzymes? b) Explain one example. If you lack any one of the digestive enzymes, you will be unable to break down and absorb all of the nutrients in your diet. This can have many side effects and lead to gastrointestinal conditions. People with diabetes mellitus, or diabetes either do not produce insulin, or lack the ability to use the insulin they produce. Without insulin, cells cannot take in glucose. This results in excess glucose in the blood being excreted in the urine. 9.4 Disorders of the Digestive system (p275-279) Create a table or a mindmap/concept map below that list some (3+) digestive system disorders, where they occur and that gives a brief description of the disorders (key words and images only). Digestive Disorder (Location) Brief Description Diabetes (pancreas) Cannot use insulin. High blood glucose levels. Excess glucose in blood is excreted in urine, ultimately causing volume of urine to increase. Body ends up metabolizing fats because it cannot use glucose. Stomach ulcer (stomach) Open sores in the stomach wall caused by damage to tissue. Caused by Helicobacter pylori bacteria. Pancreatitis (pancreas) Inflammation of the pancreas Caused by drinking too much alcohol, or by gallstones. Chronic pancreatitis causes digestive enzymes secreted by pancreas to damage tissues. Hepatitis (liver) Gallstones (Gall bladder) Constipation (large intestine) Inflammation of the liver. May lead to jaundice, a yellowish colouring of the eyes and possibly skin in lighter skinned people. If untreated, can lead to chronic hepatitis, liver cancer, and death. High levels of cholesterol in bile can cause the molecules to crystallize within the gall bladder, called gallstones. This disorder does not cause pain, and thus commonly goes undetected; it can lead to other problems such as jaundice. Constipation is a disorder in which feces is not holding enough water, making excretion extremely difficult. This can irritate the blood vessels and tissue surrounding the anus.