Term
| What is the primary function of the Digestive system? |
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Definition
| Transfer of nutrients, water and electrolytes from food we eat to internal environment. |
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Term
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Definition
| 2 types - propulsive movements and mixing movements. Propulsive is also called Peristalsis. Mixing is also called Segmentation. |
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Term
| What type of function is Peristalsis and Segmentation? |
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Definition
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Term
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Definition
| Adding digestive juices to the GI tract via the mucosa, borrowed from the plasma. |
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Term
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Definition
| Biochemical breakdown of macro (complex) molecules into micro (simple) molecules. Does NOT include absorption. |
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Term
| What is the simple form of a carbohydrate called? |
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Definition
| Monosaccharides (aka sugar) |
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Term
| What is the simple form of a protein called? |
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Definition
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Term
| What is the simple form of a Fat (Triglyceride) called? |
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Definition
| Monoglyceride and free fatty acids |
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Term
| Of the three macro molecules, which one hates water? Which ones love water? |
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Definition
| Fat HATES water. Carbs and Proteins love water. |
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Term
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Definition
| The simple forms (the micro molecules) along with water, vitamins and electrolytes are transferred from the GI tract lumen into blood or lymph. |
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Term
| What organs/parts are part of the GI tract? |
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Definition
| Mouth, Pharynx, esophagus, stomach, small intestine, and large intestine (then out through the anus) |
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Term
| What organs/parts are part of the accessory digestive organs? |
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Definition
| Salivary glands, exocrine pancreas, biliary system (liver and gallbladder) |
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Term
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Definition
| The hollow interior of the GI tract |
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Term
| What are the four layers of the lumen from inside the lumen out? |
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Definition
| mucosa, submucosa, muscularis, and the serosa. |
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Term
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Definition
| Secretes mucous and enzymes. It has a lot of folds for increased surface area. |
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Term
| What does the submucosa do? |
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Definition
| This is full of blood and lymph to fight bacteria, as well as the submucosal plexis (aka it has nerves) |
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Term
| What does the muscularis do? |
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Definition
| made of smooth muscle (shortens and squeezes), myoteric plexis (also has nerves) |
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Term
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Definition
| Mesentery. Sheet of tissue that coats the abdominal wall. Secretes lubricant. |
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Term
| Name the two plexis' that make up the enteric (intestinal) nervous system? |
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Definition
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Term
| What are the two intrinsic factors involved in regulating the digestive system? |
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Definition
| Autonomous Smooth Muscle Function, and Intrinsic Nerve Plexuses |
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Term
| In the Autonomous smooth muscle function, what is the BER? |
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Definition
| Basal Electrical Rhythm. Different parts of the digestive tract have different speeds. |
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Term
| In the Autonomous smooth muscle function, what keeps the BER in check? |
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Definition
| The Interstitial Cells of Cajal - like pacesetter cells. |
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Term
| What are the two extrinsic factors that regulate the digestive system? |
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Definition
| Extrinsic Nerves (Sympathetic, Parasympathetic) and Gastrointestinal Hormones (endocrine system). |
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Term
| What are the 3 types of sensory receptors in the GI tract walls? |
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Definition
Chemoreceptors (everywhere, tastebuds, stomach to regulate acid etc).
Mechanoreceptors (stretch smooth muscle causing it to recoil, on the tongue)
Osmoreceptors (detects water concentrations) |
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Term
| Regarding the GI tract, what is a short reflex, and where does it come from? |
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Definition
| It is when the INTRINSIC nerve networks influence motility or secretion in response to specific local stimulation (the GI tract effecting the GI tract). |
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Term
| Regarding the GI tract, what is a long reflex, and where does it come from? |
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Definition
| When the EXTRINSIC autonomic nervous activity can be superimposed on the local controls to modify glandular activity and smooth muscle. (GI Tract talking to the brain and then the brain talking back to the GI tract. or vice versa). |
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Term
| Mouth - What does Salivary Amylase do? |
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Definition
| Starts the breakdown of carbohydrates. |
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Term
| Mouth - What is the function of mucous? |
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Definition
| Moisten and lubricate, buffers acids. |
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Term
| Mouth - how much saliva is made in a day? |
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Definition
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Term
| Mouth - Where is the Salivary Center? |
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Definition
| The medulla oblangata, it is sensitive to pressure, mechanoreceptors. |
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Term
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Definition
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Term
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Definition
| Carbohydrate digestion begins via salivary amylase. |
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Term
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Definition
| No nutrients, but some medications such as buccal or sublinguals, and alcohol. |
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Term
| Pharynx/Esophagus - What are the steps in swallowing? |
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Definition
1) Food is chewed up and the tongue moves up towards the back of the throat to swallow.
2) In the Oropharyngeal phase - the medulla oblangata is triggered to push the food down (peristalsis of the bolus).
3) The Uvula pops up, and the epiglottis and vocal chords fold down to cover the airway.
4) Food enters the esophagus and moves down via peristalsis. |
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Term
| Pharynx/Esophagus - What does the pharyngealesophageal sphincter prevent from happening? |
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Definition
| It prevents air from entering the digestive tract during breathing. |
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Term
| Pharynx/Esophagus - Where is the gastroesophageal sphincter and what does it prevent from happening? |
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Definition
| It is between the esophagus and the stomach - it prevents acids from going up the esophagus. |
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Term
| Stomach - what are the 3 main functions of the stomach? |
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Definition
1. Store ingested food.
2. secretes hydrochloric acid (HCl) and enzymes that begin protein digestion.
3. Produces Chyme (thick liquid mixture). |
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Term
| Stomach - what are the 4 aspects of stomach motility? |
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Definition
| Gastric Filling, Gastric Storage, Mixing, and Emptying |
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Term
| Stomach - how does Gastric filling effect motility? |
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Definition
| Receptive Relaxation - the stomach flattens reflexively with each bite, with very little rise in pressure. |
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Term
| Stomach - How does Gastric Emptying effect motility? |
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Definition
| Liquids empty first, thicker chyme needs peristaltic contractions (it doesn't go further down the tract until it is liquidy enough). |
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Term
| Stomach - What three factors regulate stomach motility? |
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Definition
| Volume of Chyme, Degree of Fluidity, and the Duodenum. |
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Term
| Stomach - how does the volume of chyme in the stomach effect motility? |
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Definition
| Too much in the stomach increases motility. |
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Term
| Stomach - how does the degree of fluidity effect stomach motility? |
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Definition
| The higher the liquid, the faster it goes. |
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Term
| Stomach - How does the duodenum effect stomach motility? |
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Definition
| Always slows - the presence of fat, the presence of a lot of acid, hypertonicity (a lot of solutes aka very concentrated) the more thick the chyme the slower it is to empty, and distension. |
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Term
| Stomach - What are the extrinsic factors effecting motility and emptying? |
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Definition
1. Emotion - sad/fearful, slows down. Aggression/Anger, speeds it up.
2. Intense Pain - inhibits motility, increases sympathetic .
3. Decreased Glucose utilization in the brain, decreases motility. |
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Term
| Stomach - What is Vomiting (and what isn't it)? |
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Definition
| Contraction of the diaphragm and abdominal muscles, and not reverse peristalsis. |
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Term
| Stomach - What can cause vomiting? |
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Definition
1. Touching the back of the throat
2. Irritation or distention of the stomach
3. Increased intracranial pressure
4. Rotation or acceleration of the head.
5. Chemical Agents (i.e. syrup of epicac)
6. Psycogenic vomiting/emotions |
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Term
| What two parts of the lining of the stomach create gastric secretions? |
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Definition
1. Oxyntic glandular mucosa which covers the body and the fundus.
2. Pyloric Gland Area (PGA) which covers the antrum. |
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Term
| Stomach - Where are the mucosal gland cells found? |
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Definition
| In deep gastric pits, which are deep pockets in the luminal surface of the stomach. |
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Term
| Stomach - What are the four types of cells found in the gastric pits of the oxyntic glandular mucosa? |
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Definition
Mucous Cells
Chief Cells
Parietal or Oxyntic cells
Enterchromaffin-like cells |
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Term
| Stomach - What do the mucous cells do? |
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Definition
| They secrete mucous, and provide lubrication and protection of the lining. |
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Term
| Stomach - what do Chief cells do? |
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Definition
| They secrete pepsinogen. Pepsinogen is inactive, and it digests proteins. |
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Term
| Stomach - What do the Parietal or Oxyntic cells do? |
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Definition
| They secrete HCl (hydrochloric acid)and intrinsic factor. HCl = stomach acids. Intrinsic Factor allows the body to absorb B12. |
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Term
| Stomach - What do the Enterochromaffin-like Cells (ECL) do? |
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Definition
| They secrete histamines. This in turn increases the acid in the stomach to kill off a potentially harmful substance or bacteria. |
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Term
| Stomach - What are the two types of cells found in the gastric pits of the Pyloric Gland Area (PGA)? |
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Definition
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Term
| Stomach - What do the G Cells secrete? |
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Definition
| Gastrin - it excites the stomach |
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Term
| Stomach - What do D Cells secrete? |
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Definition
| Somatostatin - this is the only inhibitor of the secretions in the stomach. |
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Term
| Stomach - What is hydrochloric acid for in the stomach? |
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Definition
1. Converts Pepsinogen to the active form of Pepsin (which digests proteins)
2. Aids in breakdown of connective and muscle fibers (meat)
3. Denatures protein (it uncoils it from its tertiary structure).
4. Along with Salivary Lysozyme, it kills most of the microorganisms ingested with food. |
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Term
| Stomach - What does Gastrin (secreted by G Cells) stimulate? |
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Definition
| HCl and Pepsinogen release |
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Term
| Stomach - When is Histamine introduced, and how? |
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Definition
| Released from ECL (enterochomaffin-like cells), in response to gastrin as well as ACh. Increases the HCl secretions (from the parietal cells). |
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Term
| Stomach - What does Somatostatin do? |
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Definition
| Made from the D cells, it inhibits acid secretions. As soon as HCl gets to be too much, this is released shutting off the HCl. |
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Term
| Stomach - What can stimulate secretion of more HCl? |
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Definition
| ACh, Gastrin and Histamine |
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Term
| Stomach - What can stimulate Pepsinogen secretion? |
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Definition
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Term
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Definition
| Carbohydrate digestion continues in the body of the stomach, protein digestion begins in the antrum. |
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Term
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Definition
| Alcohol and aspirin, but no food. |
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Term
| Pancreas - what are the two parts of the pancreas? |
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Definition
Exocrine (99%) - pushes into GI tract
Endocrine (1%) - Islets of Langerhans (i.e. insulin). |
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Term
| Pancreas - What are the two exocrine portions? |
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Definition
1. Enzyme - Enzymatic Secretion (acinar cells)
2. Duct - Aqueous alkaline secretion rich in sodium bicarbonate (duct cells) |
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Term
| Pancreas - What are the 3 different enzymes secreted by the Acinar cells? |
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Definition
1. Proteolytic Enzymes (breaks proteins)
2. Pancreatic Amylase (breaks carbs)
3. Pancreatic Lipase (breaks lipids) |
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Term
| Pancreas - What are the three major proteolytic enzymes (breaks proteins) secreted by the pancreas? |
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Definition
1. Trypsinogen (inactive). Enterokinase activates it, the active form is Trypsin. All three acinar enzymes turn on when Trypsinogen is turned on and becomes Trypsin.
2. Chymotrypsinogen (inactive).
3. Procarboxypeptidase (inactive) |
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Term
| Pancreas - Name the two major enterogastrones (hormones made by the stomach). |
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Definition
1. Secretin (secretes a base, sodium bicarbonate). Released via secretion when there is acid in the duodenum.
2. Cholecystokinin (CCK)- presence of fat and sometimes protein stimulates the release from the acinar cells in the pancrease. It increases lipase and proteolytic enzymes for further digestion. Slows down emptying of the stomach. |
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Term
| Liver - Name the functions of the liver. |
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Definition
1. metabolizes macro molecules.
2. detoxifies waste.
3. synthesis of plasma proteins (albumins)
4. storage of glycogen, fat, iron, copper, fat soluble vitamins.
5. activation of vitamin D
6. removal of bacteria and worn-out RBC's.
7. Excretes cholesterol and bilirubin |
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Term
| Liver - what is bile, and where is it emptied into? |
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Definition
| Bile is a secretion produced by the liver and emptied into the duodenum. |
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Term
| Liver - What are Kupffer cells? |
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Definition
| They are the liver's equivalent to a macrophage - they line the sinusoids and engulf and destroy old RBC's and bacteria (phagocytosis). |
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Term
| Liver - what is the Hepatic Portal System? |
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Definition
| It is the vascular connection between digestive system and liver. |
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Term
| Liver - What do bile salts do? |
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Definition
| They aid in fat digestion. They emulsify fat. |
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Term
| Liver - what are Micelles? |
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Definition
| Microscopic droplets that transport monoglycerides, free fatty acids, and fat soluble vitamins to the lumincal surface of the small intestine. |
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Term
| Liver - What is the purpose of the Enterohepatic Circulation? |
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Definition
| It recycles bile salts between small intestine and liver. |
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Term
| Liver - what stimulates the secretion of bile salts? |
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Definition
1. bile salts - positive feedback loop
2. Secretin
3. Vagus Nerve |
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Term
| Small Intestine - Where does the absorption take place in the small intestine? |
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Definition
Dueodenum - most
Jejunum - some
Ileum - least |
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Term
| Small Intestine - How is segmentation initiated in the small intestine? |
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Definition
| The pace setter cells produce BER. Duodenum is 12 contractions/min, Ileum is 9 contractions/min. This means that food naturally backups as it moves through the small intestines, starting out fast and slowing towards the end. |
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Term
| Small Intestine - Ileocecal Sphincter prevents what? |
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Definition
| It prevents the contamination of the small intestine with colonic bacteria. Acts like a valve, the food doesn't move backwards. |
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Term
| Small Intestine - What is the name and composition of intestinal juices? |
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Definition
| Succus Entericus: contains NO enzymes, composed of salt and mucous. Presence of chyme stimulates it's release. |
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Term
| Small Intestine - Digestion? |
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Definition
| In the lumen, it's accomplished by pancreatic enzymes. Fat is completed in the small intestines. Carbs are in process, down to disaccharides. Proteins are in the form of protein fragments. |
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Term
| Small Intestine - Where is the brush border, and what 3 types of enzymes are in it? |
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Definition
1. Enterokinase - activates trypsinogen
2. Disaccharidases (maltase, sucrase and lactase) : breaks disaccharides into monosaccharides.
3. Aminopeptidases: breaks small peptide (protein) fragments into amino acids. |
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Term
| Small Intestine - Absorption? |
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Definition
Monosaccharides, amino acids, monoglycerides, free fatty acids, electrolytes, vitamins and water are absorbed indiscriminately.
Calcium and Iron are adjusted as body needs them.
Vitamin B12 and intrinsic factor complex is absorved in the ileum. |
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Term
| Large Intestine - What is the function of the large intestine? |
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Definition
| Drying and storing the chyme it receives from the small intestine. |
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Term
| Large Intestine - Motility? |
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Definition
| Haustral Contractions and Mass Movements |
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Term
| Large Intestine - what is secreted in the large intestines? |
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Definition
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Term
| Large Intestine - Absorption? |
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Definition
| Primarily water and a little salt. |
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