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110 Cards in this Set
- Front
- Back
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What is the most important site of digestion and absorption?
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The Small Intestine!
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What is the first 10 inches of the small intestine called?
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Duedenum
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What is the Duedenum?
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It is the first 10 inches of the small intestine
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What are the three parts of the small intestine?
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Duedenum, Jejunum, and Ileum
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What are the 7 parts of the digestive tract?
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1. Mouth
2. Pharynx 3. Esophagus 4. Stomach 5. Small Intestine 6. Large Intestine 7. Anus |
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What do the Salivary glands do?
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Secrete Saliva to lubricate food and begin chemical digestion
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What does the Liver break down?
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Alcohols and some drugs
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What are the main functions of the Liver?
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Store glycogen and make proteins
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What is the digestive function of the Liver?
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Synthesizes bile!
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What is the Gallbladder?
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It is a small organ under the liver that stores and secretes bile
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What two hormones to regulate glucose homeostasis?
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Insulin and Glucagon
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Does insulin lower or raise glucose levels?
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Lowers!
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Does glucagon lower or raise glucose levels?
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Raises!
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What are the 6 essential digestive activities?
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1. Ingestion
2. Propulsion 3. Mechanical digestion 4. Chemical Digestion 5. Absorption 6. Defecation |
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What is Ingestion?
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Taking in food by mouth
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What two things make up Propulsion?
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1. Swallowing
2. Peristalsis |
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What is Peristalsis?
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It is the region of the esophagus, stomach, small intestine, and large intestine
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What kind of muscle makes up the Propulsion regions?
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Smooth muscle!
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What is Mechanical Digestion?
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Breaking food into small pieces
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TRUE OR FALSE: You break down chemical bonds during mechanical digestion.
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FALSE
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What are the three parts of Mechanical Digestion? Where do they occur?
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1. Chewing (mouth)
2. Churning (Stomach) 3. Segmentation (Small Intestine) |
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What is the purpose of Mechanical Digestion?
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To increase surface area for enzymes to act on food molecules
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Food that reaches the stomach is called what?
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Chyme!
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What is Chyme?
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It is food that reaches the stomach
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Peristalsis involves what kind of tract organs that alternately contract and relax?
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Adjacent segments of Alimentary tract organs
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Segmentation involves what kind of tract organs that alternately contract and relax?
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Nonadjacent segments of Alimentary tract organs
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In Segmentation, food moves in what direction?
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Forward then backward then forward again.
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What is Chemical Digestion?
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Chemical bonds are broken by acid and enzymes
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Digestive enzymes break down what kind of bonds?
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Strong covalent bonds!
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Macromolecules are chemically digested into what?
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Monomers!
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Most of chemical digestion occurs where?
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Duedenum of the Small Intestine
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What is Absorption?
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Digestion products and water are absorbed from the lumen of digestive tract into the blood or lymph
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Where does reabsorption occur?
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Nephrons
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For the first time, solutes are absorped from where into where?
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From the digestive tract into the blood
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Final water absorption occurs where?
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Large intestine!
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What is Defecation?
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Elimination of wastes as feces
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What are three types of super important macromolecules?
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Carbohydrates, proteins and lipids
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What are the final digestion products of Carbohydrates?
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Monosaccharides like glucose, fructose, and galactose
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What are the final digestion products of proteins?
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Amino Acids
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What are the final digestion products of lipids?
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Monoglycerides and free fatty acids
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What are the digestive enzymes that break down carbohydrates?
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Amylases, disaccharidases
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What are the digestive enzymes that break down proteins?
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Proteases
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What are the digestive enzymes that break down lipids?
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Lipases
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What are the three important enzymes that break down Carbohydrates?
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Salivary amylase, pancreatic amylase, and the brush border enzymes
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What enzymes make up the brush border enzymes (there are three)?
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The Disaccharidases: Lactase, maltase and sucrase
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If carbohydrates are simple sugars (monosaccharides), what happens for them to be digested?
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Nothing! They're just absorbed.
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If carbohydrates are larger than monosaccharides, what happens for them to be digested?
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They require enzymes to chemically digest them
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Glucose is stored in what form?
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Polysaccharides!
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What molecule is the form in which plants store glucose?
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Starch!
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CHO (Carbohydrate) digestion begins where with what enzyme?
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In the mouth with salivary amylase
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Salivary Amylase breaks down polysaccarides into smaller chains but what is there still very little of roaming freely?
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Glucose!
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CHO digestion stops where?
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Stops in the stomach!
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Why does CHO digestion stop in the stomach?
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Because the stomach acid denatures the amylase
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What is the lumen?
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Hollow center of the small intestine
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CHO digestion resumes where and with what enzyme?
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In the Small Intestine with Pancreatic Amylase
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Pancreatic Amylase is secreted from what into where?
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Secreted from the Pancreas into the Duodenum
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Final CHO digestion occurs where with what enzymes?
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On the Brush Border with the brush border enzymes
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What are the folds with large fingerlike projections called in the small intestine?
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Villi
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What are Villi?
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They are large fingerlike projections in the folds of the lumen of small intestine
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Each villus is covered with what?
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Absorptive cells!
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Each Villum has numerous tiny extensions called what?
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Microvilli
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When especially numerous, microvilli are called what?
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Brush border
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What are digestive enzymes attached to the microvilli called?
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Brush Border Enzymes
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Table Sugar, Sucrose, is digested by what?
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Sucrase
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Grain Sugar, Maltose, is digested by what?
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Maltase
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Milk Sugar, Lactose, is digested by what?
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Lactase
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If you are lactose intolerant, what is missing or defective? What does this cause?
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Lactase Enzyme which causes it to stay in the lumen which causes water to follow and diarrhea or gas may occur
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What are proteins?
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Long chains of amino acids linked by peptide bonds
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Which enzymes break down peptide bonds in proteins?
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Proteases
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Proteases are secreted into the lumen of the digestive tract in an active or inactive form?
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Inactive!
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Why are proteases secreted into the lumen in an inactive form?
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Protect the tract from self-digestion
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Cells lining the tract, especially the stomach, secrete what to further protect and lubricate?
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Mucus!
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Where does protein digestion begins where with what enzyme?
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Stomach with HCl and the enzyme pepsin
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Gastric Pits lead to what on the inner surface?
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Gastric Glands
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HCl activates what?
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Activates pepsinogen which breaks down peptide bonds
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Gastric glands secrete what?
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HCl and pepsinogen (inactive protease)
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What pH is pepsin happy to live in?
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pH 2
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Protein digestion continues where with what enzymes?
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In the lumen with pancreatic proteases
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What are the three pancreatic proteases?
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1. Trypsin
2. Chymotrypsin 3. Carboxypeptidase |
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Pancreatic proteases are not active at what pH?
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Acidic pH
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After being in the lumen, protein digestion continues where with what enzymes?
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On the Brush Border with brush border proteases
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Where does protein digestion conclude?
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Absorptive cells with intracellular proteases
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What do the intracellular proteases digest?
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Dipeptides and tripeptides into amino acids
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Large polypeptides are digested where?
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Lumen
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Small polypeptides and small peptides are digested where?
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Brush border of small intestine
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Amino acids (dipeptides and tripeptides) are digested where?
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Within the absorptive cells of small intestine
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Why do lipids require different strategy from proteins and carbs to be digested?
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Because they're hydrophobic
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Digestive enzymes are water soluble or not?
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Water Soluble
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What make up most dietary lipids?
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Triglycerides like animal fats and plant oils
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TRUE OR FALSE: Triglycerides are very energetic and very hydrophobic.
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TRUE
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Almost all lipid digestion occurs where?
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Lumen of the small intestine
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What enzyme breaks down lipids?
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Pancreatic lipase
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Lipids must be what to be digested?
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Pretreated by emulsification with bile salts
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Are there brush border enzymes with lipid digestion?
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NO
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Bile salts in the bile mix with what?
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Mix with fat globules in the lumen
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What is emulsification?
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It is the process of which bile salts break down fat globules into fat droplets
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What type of cells make up the small intestine?
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Epithelial cells
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Bile salts coat fat droplets so they don't do what?
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Coalesce
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Is emulsification a mechanical digestion process or a chemical digestion?
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Mechanical Digestion!
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Pancreatic lipase digests triglycerides into what?
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Monoglycerides and free fatty acids
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Free Fatty Acids and monoglycerides associate with bile salts to form what?
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Micelles
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Micelles do what?
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Micelles ferry Free Fatty Acids and monoglycerides to the brush border
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What happens to fatty acids and monoglycerides leave micelles to do what?
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To diffuse into absorptive cells
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Once in the absorptive cells, fatty acids and monoglycerides recombine into what?
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Triglycerides
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Once triglycerides in the absorptive cells, what do they do?
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Become packaged with cholesterol and proteins to form chylomicrons
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What are chylomicrons?
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Triglycerides packaged with cholesterol and proteins
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Chylomicrons enter what to be carried away from the intestine by the lymph?
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Enter lacteals
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What are lacteals?
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They are lymphatic capillaries in the villi
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Are lacteals more or less permeable than blood capillaries?
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More!
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Once chylomicrons are extruded by exocytosis, what occurs?
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They are transported to the systemic circulation via the lymph system
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