The Gastrointestinal Tract + The Liver & Biliary Systems Flashcards
-What is Chyme?
oChyme is the food contents that PARTICALLY digested as they pass through the intestinal tract.
What is the function of the mouth for digestion?
o Mouth = Mechanical Breakdown. (Large into small/Mastication) & Lubrication by Salivary Glands.
- What is the function of the Stomach?
o Chemical breakdown by Pancreatic enzymes and HCL
Mixes contents & churns.
HCL eliminates any bacteria.
Production of intrinsic factor.
- What is the function of the Small intestine?
o 90% of total absorption of nutrients.
o Occurs mostly in ileum by villi.
- What role does villi and circular folds play in the S.I?
o Increases surface area to allow for greater absorption.
- What is the function of the Large Intestine?
o 1st Half: Reuptake of bile salts and water that get sent to the liver.
o 2nd Half: Storage and compression of fecal matter.
o Gut Flora creates nutrients from fibres that may be inadequate. (B’s)
- What are the 3 segments of the Small Intestine?
o Duodenum – (Final area of digestion) / Shortest
Creates a mucus fluid that flows through intestines. 1.8L daily.
o Jejunum – (Absorption commences) MOST
o Ileum - Absorption of B vitamins & bile salts here. (Largest)
Particularly Vitamin K, B2 (Biotin) & B5 (Pantohenic Acid (B5)
- What are the two types of muscular movements in digestion?
o Peristalsis - Smooth muscular contractions. (Snake like)
o Segmentation - circular muscle contractions that breakdown contents further.
- What is intrinsic factor?
o is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B₁₂ later on in the ileum of the small intestine.
- What does the Pancreas use to neutralize HCL in the small intestine?
Pancreas releases Bicarbonate here to neutralize HCL. This neutralization reaction protects the villi from getting damaged.
- What nutrient passes through the GI tract undigested/absorbed?
o Fibre. This later gets fermented or disgarderd.
- All blood that leaves the GI tract passes through the?
o Liver. This acts as a filter for the body removing any toxins.
- What nutrients leave the GI tract by the way of the lympathic system and why?
o Fats & Fat soluble vitmains. (ADEK)
- Digestion and absorption are coordinated by the?
o Hormonal system (Endocrine) and the nervous system. (Brain)
Brain - Controls the responses of hunger and satiety.
Endocrine - controls the release of hormones and enzymes required for digestion of food in the digestive tract.
- What are some of the hormones involved in digestion?
o Gastrin, which signals the secretion of gastric acid.
o Cholecystokinin, which signals the secretion of pancreatic enzymes.
o Secretin, which signals secretion of water and bicarbonate from the pancreas.
o Ghrelin, which signals when you are hungry.
o Gastric inhibitory polypeptide, which stops or decreases gastric secretion. It also causes the release of insulin in response to high blood glucose levels.
- What are the enzymes involved in digestion?
o Amylase, produced in the mouth. It helps break down large starch molecules into smaller sugar molecules.
o Pepsin, produced in the stomach. Pepsin helps break down proteins into amino acids.
o Trypsin, produced in the pancreas. Trypsin also breaks down proteins.
o Pancreatic lipase, produced in the pancreas. It is used to break apart fats.
- What are pancreatic enzymes?
o trypsin and chymotrypsin to digest proteins;
o amylase for the digestion of carbohydrates;
o lipase to break down fats.
- What the major sites of nutrient absorption are within the GI tract?
o Small intestine & Large intestine.
- What the components of the GI tract are; and what the accessory organs of digestion are?
o Main: mouth, esophagus, stomach, small intestine, large intestine, rectum and anus.
o Accessory: salivary glands, liver, gallbladder, and pancreas ,
- What the major physiological functions of the liver are:
o Bile production and excretion
o Excretion of bilirubin (RBC that have broken down), cholesterol, hormones, and drugs
o Metabolism of fats, proteins, and carbohydrates
o Enzyme activation
o Storage of glycogen, vitamins (ADEK), and minerals
o Synthesis of plasma proteins, such as albumin, and clotting factors
o Blood detoxification and purification
- What the major function of bile is in the digestion of dietary lipids:
o Bile salts perform two important functions in the digestive tract: Act as detergents, emulsifying large fat droplets into small ones. This action creates a much larger surface area for the action of lipase in the small intestine, thereby increasing lipid absorption.
- The functions of the liver that make it very important in regulating blood glucose levels
o Glucose reserve in the body. Can create and store for when the blood glucose requires.
- The two major biochemical pathways involved in alcohol metabolism in the liver
o Alcohol is metabolized by several processes or pathways. The most common of these pathways involves two enzymes—alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). These enzymes help break apart the alcohol molecule, making it possible to eliminate it from the body.
- Why a decreased NAD+/NADH ratio may occur with high alcohol ingestion
o Builds tolerance:
Alcohol metabolism is an oxidative reaction.
Enzymes (Alcohol dehydrogenase (ADH) gives off H atoms.
NAD+ -> NADH+H
Follows conversion from Ethanol -> Acetaldehyde -> Acetyl-CoA.
- How alcohol is eliminated from the body
o Liver oxidizes 90% of alcohol introduced into the blood stream.
o Elimination occurs by 5-10% metabolized in breath, urine & sweat
- What the role of the gall bladder is indigestion:
o Gallbladder stores and concentrates bile when it isn’t being excreted into the small intestine.
o Stimulated by Cholecystokinin (CCK) which actives the ODDI sphincter to release BILE
