122 GI part 7 Digestion

Absorption of Water 1. We ingest about __L of water a day. When you add all the GI secretions, you get about __L of water in the GI. About __L are absorbed in the small intestine each day. Over ___% of water is reabsorbed in the ____ via ___ 2. The rest of the water (about __ L) of water enters the colon each day (passes through the ileocecal valve). Colon absorbs most of this water. Only __L of water is lost in the feces! Max amount of water that the colon can absorb: __L 3. If there was too much water left in the lumen --> ___ (watery stool)

1. 1.5L, 9L, 7L, 90%, small intestine, osmosis 2. 2L, .15L, 4.5L 3. diarrhea

Protein Digestion 1. Must be in _____ form to be absorbed 2. 3 enzymes responsible for protein digestion

1. Amino acid 2. Pepsin, pancreatic peptidases, brush border enzymes

Bile 1. Contains ___, ___, ____, ___, ___, and ___ (BCSFFMP) 2. Bile acids form the ___. It stays in the lumen after the fat droplet is absorbed UNTIL farther down in the ___. A transporter then reabsorbs the acids into the blood. Delivered to the liver hepatocytes to be recycled and used again. More bile salts reabsorbed --> indicates more ___ in the lumen --> more bile made 3. Fat-soluble vitamins include vitamins __, __, __, and __. Need the ___ formation to be absorbed (must have bile acids to absorb these vitamins)

1. Bile acids, Cholesterol, Steroid hormones, Fat-soluble vitamins, Free fatty acids, Monoglycerides, Phospholipids 2. Micelles, ileum, fat 3. A, D, E, K, micelle

Brush Border Enzymes 1. 2 enzymes that breaks oligosaccharides --> disaccharides 2. Lactase breaks up lactose into ____ and ____ 3. Maltase breaks up maltose into 2 ____ molecules 4. Sucrase breaks up sucrose into ___ and ____

1. Dextrinase, Glucoamylase 2. Galactose and glucose 3. Glucose 4. Fructose and glucose

Fat Digestion 1. Fat must be in the small individual ____ to be absorbed. Majority happens in the _____ 2. The 2 enzymes involved are ___ and ___ 3. ____ enzyme: released in the ____ (released via salivary glands or stomach glands). Begins __ digestion but very minor. 4. ______: released into the ___, does the majority of fat digestion. ____ help emulsify the fat into smaller droplets. This increases the solubility of the lipids when in ___ form and increase the ____ --> more lipases can access the fat at one time --> faster/more efficient absorption. 5. There are __ lipolytic enzymes that break fat into ____ and fatty acids, ____ and fatty acids, and the the smallest fat molecules

1. Fatty acids, small intestine 2. Lingual/Gastric Lipase, Pancreatic Lipases 3. Lingual/Gastric Lipase, stomach, fat 4. Pancreatic Lipases, duodenum, Bile acids, micelle, surface area 5. 3, monoglycerides, glycerol

Protein Absorption 1. Absorption into the absorptive cell via ___ cotransporters. 2. Across the ______ (transporters as well on this side) 3. Enter the ____ to the _____ then to general circulation

1. Na 2. basolateral membrane 3. blood stream, liver

Carbohydrate Digestion 1. Carbs are ____ that needs to be broken down into monosaccharides 2. _____: released in the mouth, actualy digestion occurs in the upper stomach. Begins _____ (minor). Deactivated in stomach by acid 3. ___: Released by the ___ into the ____. More effective than salivary amylase. Further digests ___ via ___ (breaks it into ___ and ____) 4. _____: Breaks the ____ and ____ into _____. Located in ____ of the absorptive cells on the luminal membrane. 5. Examples of disaccharides? 3 of them 6. Examples of monosaccharides? 3 of them

1. Polysaccharides 2. Salivary amylase 3. Pancreatic amylase, pancreas into the duodenum, polysaccharides, hydrolysis, (oligosaccharides and disaccharides) 4. Brush Border Enzymes, oligosaccharides and disaccharides, monosaccharides, microvilli 5. Lactose, Maltose, Sucrose 6. Glucose, Galactose, Fructose

Carbohydrate Absorption 1. Carbs brought into the absorptive cells via transporters in the brush border absorptive cells. The 2 transporters are ___ and ____ 2. ____: transports ___ and ____. Also a ___ cotransporter (Requires an ___ molecule to be brought in along with the monosaccharides. It provides the driving force/energy) 3. ____: transports ____ via ____. Less efficient so some ___ may remain in the lumen and not fully be absorbed. It may keep some water in the lumen which leads to ____. Simply brought into the cell so no ___ needed 4. When particles are absorbed from the lumen, ___ is pulled along with them via absorption. SO most of the ___ absorption occurs in the ____ as well (where all the solutes are being absorbed) 5. The carbs exit the other side of absorptive cells through the ____ membrane. _____ transports glucose, galactose, and fructose into the lamina propria. ___ is also delivered via another unknown transported. 6. Food must be brought in from the _____ in the lamina propria into the capillary beds. Blood is then delivered to the ___ for filtration, then enter the general circulation

1. SGLT 1 Transporter, GLUT 5 Transporter 2. SGLT 1 Transporter, galactose and glucose, Na 3. GLUT 5 Transporter, fructose, facilitated diffusion, diarrhea, Na 4. water, water, duodenum 5. basolateral membrane, GLUT 2, fructose 6. interstitial fluid, liver

1. _____ is Main Digestion and Absorption Site. It has ___, ___, and ___ to increase surface area 2. What is pathway of food after digestion? 10 parts 3. Proteins must be broken into ____ to be absorbed Lipids must be broken into ____ Carbohydrates must be broken into ____

1. Small Intestine, plicae, villi, and microvilli 2. Lumen --> mucosal epithelium (absorptive cells) --> lamina propria --> capillary beds in lamina propria --> venule --> hepatic portal vein --> liver sinusoids for filtering --> central vein of lobule --> hepatic veins --> inferior vena cava 3. amino acids, free fatty acids, monosaccharaides

Electrolyte Absorption 1. Absorbed along the small intestine mostly, via ___ into the absorptive cells and into the blood (use transporters) 2. ____: usually brought in with many other molecules. Provides driving force 3. Calcium is brought in via ____ 4. Water soluble vitamins include vitamins __ and __. Absorbed mostly in the small intestine via ___. Concentration gradient drives the absorption -concentration is much higher in the lumen --> driven into the absorptive cells and then into the blood 5. Vitamin __ is special. Needs ____ and must form a complex to be absorbed. Is ____ transported not via diffusion 6. Fat soluble vitamins include vitamins __, __, __, and ___. They enter the ___ not the blood stream. Absorption pathway is the exact same path as fat.

1. active transport 2. Sodium 3. active transport 4. B, C, DIFFUSION 5. Vitamin B12, intrinsic factors, actively transported 6. A, D, E, K, lacteals

Colon Absorption 1. Any ___ and ___ that weren't absorbed in the small intestine can be absorbed here. Most water and nutrients are absorbed previously in the small intestine

1. amino acids and peptides

Fat Absorption Lipoproteins 1. Chylomicron: the proteins + fat from the absorptive cells, from _____ ___ 2. Low Density Lipoprotein: __ cholesterol. Much lower ___:__ ratio 3. High Density Lipoprotein: __ cholesterol. Much higher __:__ ratio (about __% protein) 4. They will be processed in the liver later. Enter the liver via the ____ not the ___ because they came in with the systemic circulation 5. Fat processing occurs in the liver in the ___. May be made into a ___, ___, ___, etc.

1. dietary fat 2. bad, protein:fat ratio 3. good, protein:fat (45%) 4. hepatic artery, hepatic portal vein 5. hepatocytes, steroid, cholesterol, bile acid

Gastric Absorption 1. Very little nutrients are absorbed in the stomach. Most occurs in the ___ of the small intestine, remember. 2. Rate of absorption in the stomach depends on ____ 3. ____: Very small and very water soluble. Can be absorbed very easily ANYWHERE (including the stomach). During ____, peak blood alcohol concentration will be reached within 30 minutes. 4. ___: Unionized in low __. Absorbed much faster! The ion can cross the membranes more easily. SO in an empty stomach, aspirin is mostly absorbed in the stomach. In a full stomach, less aspirin will be absorbed because the __ will be higher. Will also be brought into the small intestine due to ____ ____ along with the food. Aspirin may damage the ___ and ____. Will cause more damage when taken on an empty stomach -won't be coated with other foods and diluted. Take aspirin with food!

1. ileum 2. stomach emptying 3. Ethyl Alcohol, fasting 4. Aspirin, pH, pH, gastric emptying, GI mucosa and epithelial layer,

Fat Absorption 1. Brought into the absorptive cells. Can diffuse in because it is so ____. No transporters needed. 2. Within the cell, it is reesterified into a _____. A protein coat is added as well. Forms a Forms a ____ (protein coat + fat). Provided by the _____. Helps keep the fat soluble enough to travel via the blood stream (more hydrophilic) 3. Absorbed across the basolateral membrane. A vesicle surrounds the _____ coat and fuses with the basolateral membrane to exocytose it 4. Absorbed into the ____, not the blood stream. These lymph capillaries are called ____ located in the center of a single ____ (right next to blood capillaries). Channeled into ____ --> _____ --> into ____ --> systemic circulation 5. Transport in the blood: transported as _____. The 4 types are ____, ____, ____, and ____

1. lipophilic 2. triglyceride, chylomicron, golgi apparatus 3. chylomicron 4. lymph vessels, lactals, villus, lymphatic vessels, thoracic duct, veins 5. lipoproteins, chylomicron, LDL, HDL, VLDL

Other Causes of Diarrhea 1. Food materials that can't be absorbed will keep water with it. Water follows the ____ 2. Examples are ___ (it isn't absorbed as well as glucose) and ____ (Caused by a person has less lactase enzyme, May also cause __ because the bacteria can use that sugar left behind as nutrients and will grow)

1. nutrients 2. fructose, lactosintolerance, gas

Intestinal Absorption 1. Site of most nutrient absorption because there is so much surface area from the ___, __, and ___. Also, by the ileum, they have been fully digested into units small enough to be absorbed. _____ exist on the absorptive cell membranes to bring in the nutrients 2. Functional unit of absorption: ___ 3. Transport can be ____ (molecules go through the cell cytoplasm itself, uses transporters) or _____ (molecule goes between the two cells, ____ keep the cells very close together

1. plicae, villi, and microvilli, Transporters 2. villus 3. transcellular, paracellular, tight junctions

Protein Digestion Enzymes 1. Pepsin: released by ____ cells as ____ into the stomach lumen. Activated via the acid of the stomach. Begins protein digestion into large ____ chains via ____ (minor). Very important for ___ digestion (found in meats) 2. Pancreatic Peptidases: released into the ____. Break the large polypeptides into smaller polypeptides/peptides. The 3 enzymes involved are ___, ___, and ___ 3. Brush Border Enzymes: Found on microvilli of absorptive cells, found especially in the _____. Breaks the small polypeptides into _____. The 3 enzymes involved are ___, ___, and ___ 4. SOME _______ can be absorbed via specific transporters

1.Chief cells, pepsinogen, polypeptide, gastric hydrolysis, collagen 2. Duodenum, Trypsin, Chymotrypsin, Carboxypeptidase (3 types) 3. Jejunum, amino acids, Aminopeptidases, Carboxypeptidases, Dipeptidases 4. dipeptides/tripeptides