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126 Cards in this Set
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Definition of The Digestive Tract |
Responsible for converting what we eat and drink into substances our bodies need to function |
Food and Water Consumption |
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Substances our bodies need to Survive |
Water, Proteins, Carbohydrates, Lipids, Amino Acids, Minerals, Vitamins |
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Ingestion |
Food enters the GI tract through the oral cavity |
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Oral Cavity |
Consists of the Mouth, Tongue, Teeth, Salivary Glands, Epiglottis, Pharynx, and Esophagus |
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Digestion |
Food is passed from the oral cavity to the Stomach and Small Intestine, where it will then be broken down |
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Mechanical Digestion |
A process where complex substances are broken down into smaller more absorbable pieces WITHOUT BEING CHEMICALLY CHANGED |
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Chemical Digestion |
Complex Substances are CHEMICALLY BROKEN DOWN into smaller more absorbable pieces |
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Absorption |
Material from the "Broken Down Food" can be used by the body is absorbed by the small and large intestines |
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Egestion |
Indigestible material and waste must be removed by the body, so the materials are passed to the rectum and released through the anus |
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The Mouth |
Consists of Cheek, Lips, Vestibule, Hard Palate, Soft Palate |
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Cheek |
Supports the Oral Cavity and holds food |
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Lips |
Keeps food in the mouth during chewing |
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Vestibule |
Gap between lips and gum |
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Hard Palate |
"Roof" of mouth supported by bone |
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Soft Palate |
"Roof" of mouth supported by Skeletal Muscle |
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The Teeth |
The primary Agent of Mechanical Digestion |
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How many sets of teeth do humans have? |
Two: 20 Deciduous Teeth (Baby Teeth) which are replaced with 32 Permanent (Adult Teeth) 12 of which are molars |
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Regions of the Tooth |
The crown ~> Top of The Tooth The Neck ~> Central area that contains the gum and nerve endings The Root ~> Area below the guns that contain blood on supporting structures |
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Enamel |
Covers the Crown of the Tooth Is the hardest substance in the Human Body |
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Nerves in the Tooth |
Are found in the neck (register Sensation |
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Pulp Cavity |
Hollow Tube that Runs through the middle of the tooth that contains blood vessels and nerve cells |
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Dentin |
Hard Tissue that supports the enamel and DOES NOT CONTAIN NERVE ENDINGS |
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Periodontium |
Holds the root of the tooth in the Jaw |
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Cementum |
Bone with a high concentration of connective tissue |
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Gums |
Tissue that surrounds and supports the teeth and associated tissues AKA The Gingiva |
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Tinsils |
Part of the Immune System Act as a filter for foreign material in the mouth |
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Pharynx |
Group of Muscles that Coordinate Swallowing Controls the intersection between the Digestive And Respiratory System |
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Epiglttis |
Found in the Pharynx A flap of tissue that prevents food from entering the trachea |
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Eustachian Tube |
Found in the Pharynx Equalizes pressure between the Middle ear, throat, and nasal cavities |
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Salivary Glands |
Produce saliva |
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Sublingual Glands |
A set of Salivary Gland |
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Submandibular Glands |
A set of Salivary Glands |
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Parotid Glands |
A type of Salivary Gland |
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Saliva |
Contains the enzyme Salivary Amylase Contains various other enzymes that clean the surface of the mouth Lubricates food |
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Salivary Amylase |
Chemically breaks down STARCH into GLUCOSE (Hydrolosis) |
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Tongue |
Primary Organ of the Oral Cavity Contains 2 parts: The root- Contains a series of muscles and nerve endings that link the tongue to the nervous system The Body- involved in eating and drinking Surface is covered in Papillae |
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Papillae |
Taste Buds Can only detect 4 tastes "Salty, Sweet, Sour, and Bitter"
It is the proportions of these combined with our sense of smell that determines the "taste" of our food |
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The Esophagus |
A long tube that connects the oral cavity to the stomach Uses Peristalsis to move food down to the stomach |
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Swallowing => Stage 1 |
Food is Mechanically Digested by the Teeth The Tongue mixes the mechanically digested mass with saliva from the salivary glands to form a Bolus |
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Swallowing => Stage 2 |
The tongue passes the bolus towards the pharynx The pharynx forces the tongue to press against the hard and soft palate of the mouth |
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Swallowing => Stage 3 |
The Pharynx closes the Epiglottis which seals the Trachea so that food DOES NOT ENTER the respiratory system The movement of the tongue triggers Peristalsis along the Pharynx and Esophagus that carries the bolus to the Stomach |
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The Stomach |
Once the Bolus has been swallowed it moves down the esophagus into the stomach A "J" shaped organ of the abdominal cavity where digestion occurs |
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Fundus |
The first part of the Stomach closest to the Esophagus Holds gases that are released during digestion |
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The Pylorus |
The Third part of the Stomach Closest To The Duodenum The exit point of the stomach |
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How long does the Bolus spend in the stomach? |
2-3 hours |
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Structure and Function of the Stomach |
Entry into stomach is controlled by the Cardiac Sphincter |
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Cardiac Sphincter |
A ring of muscle around the Pylorus Makes sure food enters slowly Prevents the backflow of food into the Esophagus |
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The Body of the Stomach |
The stomach is lined with a mucous membrane called the Mucosa. The biggest part of the stomach Responsible for the formation of Chyme |
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Gastric Glands |
What the Mucosa is composed of Contains Parietal Cells Epithelial Cells Chief Cells |
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Parietal Cells |
Found in the Gastric Glands of the Mucosa Produce Hydrochloric Acid (HCI) that is used to chemically break down proteins |
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Epithelial Cells |
Produce Mucous that protects the stomach from the affects of Hydrochloric Acid (HCI) |
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Chief Cells |
Produces the ENZYME Pepsinogen |
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Pepsinogen |
Enzyme produced by Chief Cells When Pepsinogen comes into contact with HCI it becomes active and is called Pepsin |
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Pepsin |
Produced when Pepsinogen comes into contact with HCI Speeds up process of Protein Digestion |
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Rennin |
Secreted by the Mucosa Slows the movement of milk and deprecated it into whey (will be digested where it is) and curds (carbohydrates) so that it can be digested and absorbed |
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Gastric Juices |
The combination of Pepsin, Rennin, and Hydrochloric Acid in the Stomach |
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What Causes the stomach to contract? |
The stomach is surrounded by a series of muscle layers that cause the stomach cavity to expand and contract |
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Rugae |
Small ridges in the Mucosa |
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Formation of Chyme |
As the stomach churns, food is mixed up and dragged across these ridges until it becomes liquid |
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The Duodenum |
The first segment of the small Intestine and the second major site of digestion in the body Chyme gets broken down further 90% of digestion occurs here with the help of accessory organs |
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Pyloric Spincter |
A ring of muscle around the Pylorus Controls the flow of Chyme from the stomach to the duodenum |
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What are the 3 "Juices" that are active in the Duodenum? |
Pancreatic Juice Bile Intestinal Juice |
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Pancreatic Juice |
Produced by the Pancreas When the Acidic Chyme enters the Duodenum, the acid triggers the hormone prosecretin to activate into Secretin |
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What does Prosecretin activate into? |
Secretin When the acidic chyme enters the Duodenum the acid triggers the hormone to activate into Secretin |
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What does Secretin do? |
Secretin triggers the Pancreas to start releasing Pancreatic Juice into the Duodenum through the Pancreatic Duct |
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What does Pancreatic Juice Contain? |
Bicarbonate Ions Trypsinogen Pancreatic Amylase Pancreatic Lipase |
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Bicarbonate Ions |
Found in Pancreatic Juice Act as a buffer and neutralize the acid in the chyme (raises pH from 2-6) |
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Trypsinogen |
Activated into Trypsin in the Duodenum and breaks large polypeptides into diepetides |
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Pancreatic Amylase |
Found in Pancreatic Juice Breaks STARCH into GLUCOSE |
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Pancreatic Lipase |
Breaks FAT molecules into FATTY ACIDS and GLYCEROL |
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Bile |
Form of Mechanical Digestion PRODUCED by the LIVER and STORED IN THE GALL BLADDER NOT AN ENZYME Emulsifies Fat MECHANICALLY |
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Cholecystokinin |
A hormone that is released when fat reaches the Duodenum Triggers the Gall Bladder to release bike into the duodenum through the Bile Ducts |
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What happens after Bile emulsified fat? |
The smaller the fat molecules the easier it is for the enzymes to break them down CHEMICALLY into Glycerol and Fatty acids |
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Intestinal Juice |
Produced in the duodenum by the KRYPTS OF LEIBERKUHN Intestinal cells secrete fluid that contains the following Enzymes : Jntestinal Lipase Erepsin Disaccharases |
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Intestinal Lipase |
Found in Intestinal Juice produced by the duodenum Breaks fat globules into fatty acids and glycerol |
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Erepsin |
Found in the Intestinal Juice Produced by the Duodenum Breaks down proteins into Amino Acids |
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Disaccharases |
Breaks Disaccharides into Monosaccharides |
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What is the major organ of digestion? |
The small intestine |
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What does the Small Intestine do? |
Major organ of Digestion and absorption |
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The Small Intestine |
7m long Attached to the abdominal wall by mesentary that contains blood supply |
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How many parts does the small intestine have? |
3: Duodenum Jejunum Ileum |
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Jejunum |
Second part of the small intestine LONGEST PART OF THE SMALL INTESTINE Responsible for additional digestion and absorption |
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Ileum |
FINAL SECTION IF THE SMALL INTESTINE Absorbs remaining nutrients from the chyme |
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The Mucosa |
Inner lining of the stomach Arranged in ridges call villi |
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What is the difference between Rugae and Villi? |
The Rugae are found in the stomach whereas the Villi are found in the small imtestine |
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Villi |
Ridges in the Mucosa Increase surface area of the small intestine in order to allow for more efficient absorption of nutrients Each Villus contains many structures : Epithelial Cells Krypts of Leiberkuhn Lacteal Capillaries |
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Krypts of Leiberkuhn |
Digestive glands found at the base of the villi (that are in the DUODENUM and JEJUNUM) Release intestinal Juice |
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The Lacteal |
A lymph vessel that absorbs the fatty acids and glycerol |
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Cuboidal Cells |
Lining of the villi that contain MICROVILLI to increase surface area |
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Capillaries |
Nutrients move through the Cuboidal cells into the Capillaries. Absorb: Monosaccharides, amino acids, vitamins, minerals INTO THE BLOOD |
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Purpose of The Small Intestine |
In the presence of food it is ALWAYS MOVING |
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4 Main Function of the Small Intestine |
Squeeze Chyme through the Intestine Mix Chyme with the Digestive Enzymes Break Down food particles MECHANICALLY Speed up absorption by bringing the Chyme into Contact with Mucosa |
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Enzymes |
A biological Catalyst that SPEEDS UP CHEMICAL REACTIONS WITHOUT BEING CONSUMED OR ALTERED Will lower the activation energy, thus making it easier for a CHEMICAL REACTION TO TAKE PLACE Protein Molecules |
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The Active site of an Enzyme |
A region where the REACTANTS binds and where the chemical reaction TAKES PLACE When the reaction has taken place the substrate is released from the active site and the ENZYME REMAINS UNCHANGED |
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Substrate |
A Reactant that binds to the active site of an enzyme |
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What is a Reactant? |
A substance that is going to react |
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How many substrates can bind to the active site of an enzyme? |
More than one substrate can bind to the active site of an enzyme depending on the type of reaction that will take place |
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What is the Enzyme-Substrate complex? |
The binding of the Substrate to the active site of an Enzyme |
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Inhibitors |
When an Enzyme is not needed an Inhibitor will bind to the enzymes active site This BLOCKS THE SUBSTRATE THUS PREVENTING A CHEMICAL REACTION FROM OCCURING |
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The Large Intestine |
Undigested and Unabsorbed material pass from the small intestine to the large intestine ~1.5m long NO DIGESTION OCCURS IN THE LARGE INTESTINE Contains 5 Parts: Cecum The Appendix The Colon The Rectum The Anus |
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What percentage of digestion occurs in the large attention? |
NO DIGESTION OCCURS IN THE LARGE INTESTINE |
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Cecum |
First part of the Large Intestine Chyme enters through the illocecal valve Contains intestinal Bacteria that breaks down cellulose that is still present in the Chyme |
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Illocecal Valve |
The entry point of the Cecum from the Small Intestine Chyme first enters the Large Intestine through here |
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Why is Cellulose important for digestion? |
Cellulose of "Bulk-Fibre" that is used to trigger bowel movements |
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The Appendix |
Second "Part" of the Large intestine Stores the small amount of Cellulose that is broken down by intestinal bacteria A vestigial organ (no function) If inflamed it can rupture |
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Intestinal Bacteria |
Found in the Cecum Breaks down Cellulose that is still present in the chyme |
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The Colon |
Third "Part" of the Large Intestine Divided into the Ascending, Transverse, Descending, and Sigmoid regions Absorbs Vitamins B and K |
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Where is Water reabsorbed in the body? |
In the Colon (Large intestine) As chyme passes through the regions of the colon, water is reabsorbed |
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How much of the digestive fluid is used by the body each day? |
7L of the body's digestive fluid is used everyday |
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The Rectum and The Anus |
The edge of the Large intestines Feces is passed to the holding area (Rectum) until a bowel movement occurs The regular the bowel movements are, the less time the toxins can stay in the body |
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What is the Anal Sphincter? |
The ring of muscle that controls the exit of the GI Tract |
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Feces |
Undigestible remains of the CHYME ~ 60% solid, 40% liquid Contains Bile, Cellulose, Bacteria, Water, and other materials the body can't use |
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Diarrhea |
When too little of the water drank is absorbed by the intestine |
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Constipation |
Too much water is reabsorbed by the body |
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The Liver |
A two lobed organ associated with DIGESTION and FILTRATION and STORAGE |
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Where does the liver receive its blood supply? |
Hepatic Artery |
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Where does the liver receive the blood it is to filter? |
The HEPATIC PORTAL VEIN from the INTESTINES |
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Where does the filtered blood exit the liver to return to the heart? |
Hepatic Vein |
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Liver Filtration |
After nutrients are reabsorbed by the VILLI, the blood is carried to the Liver via the HEPATIC PORTAL VEIN |
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What does the Liver remove from the blood? |
Any toxins that may be present in the blood. |
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Blood Sugar Maintenance |
The LIVER ACTIVELY REMOVES GLUCOSE FROM THE BLOOD Excess Glucose is converted into Glycogen and stored in the LIVER |
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What Happens when there is a drop of glucose levels in the blood? |
Is there is a drop of glucose levels, the liver will convert the Glycogen into Glucose |
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Liver Waste Management |
The LIVER converts AMINO ACIDS and AMMONIA into UREA which is then removed from the body |
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What does the Liver store and produce? |
The liver stores VITAMINS A, D, B12 and IRON The Liver produces Vitamin A, and CHOLESTEROL used in the formation of the cell membrane The Liver also produces proteins for blood clotting and globulins to fight infections |
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What is Stored in the liver? |
Vitamins A, D, B12 and Iron |
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What is produced by the Liver? |
Vitamin A, Cholesterol, and Proteins used for blood clotting and Globuling to fight infections |
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