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122 Cards in this Set
- Front
- Back
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Digestion of ____ and ____ of nutrients are accomplished in a long tube connected to the external world as both ends; ____ and ____ of "the tube" are major themes in understanding the gut.
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food
absorption secretion motility |
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____ - breaking food products down chemically (enzymes) or mechanically - churning, muscle contractions
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Digestion
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____ - what am I secreting out of my body, or secreting out of the digestive cells into the lumen, into the cavity where digestive stuff is
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Secretion
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____ - what I am taking from the lumen of the digestive tract into the blood stream
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Absorption
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___ - mechanical or muscular movement that is propelling food down the tract, churning can help with the digestive process
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Motility
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The majority of the ____, ____ and ____ takes place in the small intestine.
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absorption
digestion secretion |
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The four processes carried out by the GI tract:
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Digestion
Secretion Absorption Motility (DAMES in bio 181) |
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Note! Food ____ go through accessory organs
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does not
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4 gut layers -
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Mucosal layer
Submucosa Muscularis externa Serosa |
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____ - dense connective tissue, to close, bind and protect this digestive tract
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4th layer - serosa
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____, much larger layer of muscle - at the top of the digestive tract mouth etc, it is voluntary
As you go down the digestive tract it becomes smooth/involuntary |
3rd layer - muscularis externa
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____ - it has most of the blood and nerve tissue and is not shown here but, blood and nerve tissue extends out to other layers to help innervate etc out of the whole digestive tract.
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2nd layer - submucosa
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____ - filled with endocrine and exocrine cells, transport cells (lots of absorption) - an epithelial lining filled with nooks/cavities to maximize absorption
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top layer (above is the lumen)
Mucosal layer |
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____
Lymph system Primarily in the upper GI tract - the tonsils, etc ___ tries to disinfect what we are trying to eat… |
Lamina propria - (MALT - mucusa associated lymph tissue)
LP w/in the mucosal layer |
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Other layer of cells in the ____ is a very small layer of muscle (smooth = involuntary) = ____, can contract rythmically and push food down the tract
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mucosal layer
muscularis mucosa |
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____ - fringe the villi to further increase surface area.
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Microvilli/brush border
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Whole ____ is to increase surface area to get maximum efficiency out of the digestion and absorption process
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SI
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By projecting into the ____, the ____ increases the surface area for absorption of nutrients.
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lumen
villi |
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Normally when we are ____ we can breathe through our nose or mouth, most of the time the passageway is open so I can breathe.
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not swallowing
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First we chew chew chew, increases surface area of the food, mouth is the place to ____ start digestion of the food, and will mix with saliva, moistening the food and has a few ____.
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mechanically
enzymes |
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____ - begins the chemical digestion process for starches
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Salivary amylase
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____ - lipase breaks down fat/lipids
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Lingual lipase
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Optimum pH in mouth (and those enzymes) is fairly neutral ___
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6.5 to 7.0
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When I swallow, the ____ will swing shut and block the entrance into the ____ and the food will go down the right tube.
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epiglottis
trachea |
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The swallowing ____ is coordinated by the ____, which stimulated the appropriate ____ of contraction and relaxation in the participating skeletal muscle, sphincters, and smooth muscle groups.
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reflex
medulla oblongata sequence |
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Major functions of saliva
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MADD
Moistens and lubricates food Antibacterial actions (minimal amount of immune function) Dissolves food Digestion by amylase and lingual lipase |
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____ is a nice flexible tube that leads to the stomach, no digestive properties, no hormonal control - just a tube, will relax and contract rhythmically to propel that food toward the stomach,
pH will stay the same since not adding anything Salivary amylase and lingual lipase continue to work |
Esophagus
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Some sort of ____ separating each part of the digestive tract
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sphincter
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Mouth to esophagus - ____, does not work very well in babies, takes about a year to get strong enough, why they are always spitting up their food. Will open and close due to the presence of food hitting it.
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upper esophageal sphincter
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Esophagus to stomach - ____, open and close rhythmically in presence of food/bolus
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lower esophageal sphincter
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The coordinated sequence of contraction and relaxation in the upper esophageal sphincter, the esophagus, and the lower esophageal sphincter is necessary to deliver ____ to the ____.
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swallowed food
stomach |
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Food enters ____ - it will contract and relax ____
The stomach has multiple ____ layers, these ____ contract and relax to help with the whole churning process. |
stomach
rhythmically muscle muscles |
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Stomach parts -
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Fundus
Body Antrum Pyloris |
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Sphincter from stomach to SI -
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pyloric sphincter
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___ - secretes mucus, pepsinogen and HCL
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Body
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____ - secretes mucus, pepsinogen and gastrin
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Antrum
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Stomach cells -
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MCPEED
Mucus cell/Goblet cell Chief Cell Parietal Cell Enteroendrocrine Cell ECL cells D cells |
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Most of the stomach cells have a ____.
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pretty short "half life"
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____ - secrete histamine and serotonin will release in repsonse to the food bolus and land on the parietal cells to trigger the release of HCl
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ECL cells
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____ - secrete somatastatin, (remember inhibits growth hormone) in the stomach SS inhibits enteroendrocine cells that secrete the gastrin (or inhibits secretion of gastrin)
Want ____ to work when there is no food present, do not want stomach churning and acid secretion w/ no food to work on |
D cells
D cells |
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____ - secretes inactive pepsinogen
Pepsin is a protein digestor |
Chief cell
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____ - it secretes mucous, a ____
Mucus will line lumen of stomach, will protect against mechanical damage from churning but also from damage from HCl |
Mucus cell/Goblet cell
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____- This secretes a hormone called gastrin.
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Enteroendocrine cell
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____ is stimulated to be released by the presence of the low pH and its main function is to stimulate motility/contraction of the stomach muscle cells - will increase mechanical digestion
It also helps stimulate the contraction and relaxation of the lower esophageal sphincter. It also helps stimulate the production/growth of some of the other stomach cells. The gastrin will help regenerate some of these cells. |
gastrin
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___ - secrete HCl and it will secrete intrinsic factor, a peptide that is helpful in absorbing certain B vitamins
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Parietal cell
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The ____ will drop the pH to somewhere between 2 & 3, also very effective in killing bacteria (they do not like acidic environment).
Help convert ____ into pepsin. Dropping pH this low will also ____ salivary amylase and lingual lipase. |
HCl
pepsinogen inactivate |
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Common stomach condition, ____, thought it was stress, but that may be a factor a lot of ulcers are caused by (at least initially) a bacteria
Found out went in on an unrelated illness and woah, antibiotic fixed the ulcer, not all ulcers are caused by this bacteria but many are Some have a genetic component (20 percent), either ____ is released by the parietal cell, but more commonly it is caused by ____, not producing enough ____. |
Ulcers
too mcuh HCl disfunctional mucus cells mucus |
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____ - help absorb b vitamins
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Intrinsinc factor
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Pepsinogen - pre or inactive enzyme, need ____ to make this active (pepsin)
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HCl
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____ in the stomach, allow for the contents to be mechanically mixed, helps to propel those contents down toward the small intestine
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Waves of contraction
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____ driven reaction is occuring in the parietal cells
Get the ____ from the blood in exchange for the ____ (chloride shift) 2 purposes ____ transported into the capillary to buffer the blood ____ will come into the parietal cell and that sill be the source of ____ for the acid into the stomach _____ ions some at least, will be actively transported into the lumen of the stomach, and that’s the ____ source of ____ |
Carbonic anhydrase
chloride bicarb chloride chloride hydrogen hydrogen HCl |
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Chloride shift again -
Pull ____ ions in in exchange for the ____ and will Help buffer the blood pH just as before. Will send ____ ions in via an _____ - going up a concentration gradient, can use chloride ions down a conc gradient into the stomach lumen _____ can be actively transported into the lumen in exchange for ____ In the lumen hydrogen and chloride combine to form ____. |
chloride
bicarb chloride active mechanism hydrogen ions potassium HCl acid. |
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Acid production by the parietal cells in the stomach depends on the generation of ____; subsequent movement of _____ into the gastric lumen results from ____.
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carbonic acid
hydrogen ions primary active transport |
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____- means bile salts are stored back in the liver, basically not much storage capacity (very limited), can still eat fat etc, but do not have extra bile salts so do not have the capacity to eat large amounts of fat in one sitting
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No gallbladder
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Up to 95% of the cholesterol-based ____ are "recycled" by reabsorption along the intestine.
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bile salts
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____ helps with digestion, digestion functions
Aid in fat digestion- will synthesize bile salt |
Liver
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Are not an Enzyme, not digesting fat, making it easier for the lipases to attack the fat
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bile salt
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_____ leaves the liver and will travel down a _____
Will merge into the _____ The ____ will travel down the _____ and enter the SI, if food or food byproducts are present in the SI |
bile
hepatic duct common bile duct bile salts common bile ducts |
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If there is no food, I want to be able to store the ____, and will store these in a second accessory organ, the _____
In the absence of food, the ____ will be made, and travel down the ducts, but there is a sphincter the _____, that is at the end of the common bile duct (entrance to SI) those _____ will be shunted back up to the ____ for storage. |
bile salts
gallbladder bile salts sphincter of oddi bile salts cystic bile duct |
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____ bind to the fat, emulsify it (liquefy it/increasing surface are/making it more accessible to the lipases)
Also helps make it more ____ than it normally would be. |
Bile salts
water soluble |
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____ it - increasing surface area, remember lipase is the fat digester
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Emulsifying
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We absorb fat in our body as ____
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fatty acids
monoglycerides |
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Fat "digestion"
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Big droplets of fat
Bile salts and phospholipids help w/ emulsification Small droplets of fat Bile salts and then pancreatic lipase Micelles <-> <->Fatty acids and monoglycerides Which can diffuse at this point. |
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Glycogen breakdown = ____
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glycogenolysis
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Glycogen synthesis = ___
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gluconeogenesis
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____ - main blood protein responsible for oncotic pressure, for keeping fluid in the blood vessels
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Albumin
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____ is also responsible (beside bile salts) for synthesizing the large blood proteins, specifically ____
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Liver
albumin |
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3rd function - also responsible for converting toxic ammonia (NH3) that its getting from protein breakdown into a less toxic ____, much of that ____ gets excreted as ____.
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urea
urea urine |
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4th function - the liver can store _____ (can store fat) some of that fat is stored so I can synthesize ____, some of that ____ is used to produce the ____, some is used to produce new ____
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triglycerides
cholesterol cholesterol bile salts plasma cell membranes. |
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5th function - the liver can store excess sugar as ____, when _____ levels are low, the liver can break down the ____ and release it into the blood as ____
The liver can also convert nonglycogen or nonglucose substrates into ____ (certain amino acids, etc ) if need be. |
glycogen
blood glucose glycogen glucose glucose |
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Numbers - want to understand how much _____ goes on, vast majority of it is _____
For nutrients, or be dehydrated in a matter of minutes, Tremendous amount of ____ but most of it we keep. |
reabsorption
reasbsorbed secretions/ingestion |
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____ - has both an endocrine and exocrine function, that is secretes both enzymes and hormones
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Pancreas
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Pancreas has a ____ leading into the top portion of the small intestine
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common pancreatic duct
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____ - from stomach, stimulate acid secretion, motility of stomach, it inhibited by excess acid in stomach and by SS
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Gastrin
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____ - released by the SI, produced by the SI.
It is stimulated by food byproducts coming into the SI. (chemically responding to carbs and fats). Its target tissue is back in the _____. It will ____ gastric motility and gastric secretion, (smaller role but does inhibit). Do not want gastric functions if ____ is leaving. ____ also ____ the release of insulin from the pancreas. |
GIP (Gastric Inhibitory Peptide)
stomach inhibit food GIP stimulates |
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Digestive secretions from the liver and the pancreas are delivered into the duodenum of the small intestine through the ____.
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sphincter of oddi
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Food enters SI from the stomach, and will enter through the pyloric sphincter This opens and closes rhythmically, will respond to the presence of the ____ and will allow small amounts into the ____ each time it opens.
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acidic chyme
SI |
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The pancreas releases ____ into the SI that will help digest fats, carbs, and proteins. (don’t need super specific but pancreatic amylase, from the pancreas and digests carbs)
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enzymes
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____ is site of most of the absorption and digestion.
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SI
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(A lot of the ____ to release of the ____ etc is the presence of the ____, or the specific ____ releasing signals.)
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triggers
enzymes food macronutrient |
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Very alkaline/Bicarb secretion from the ____ to neutralize the ____. Do not want to damage ____ cells and cant have ____ there (would block the absorption)
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pancreas
acidic chyme SI mucus |
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The optimum pH of the SI is ____.
This pH change inactivates the ____ and helps ____ all the enzymes that come from the ____. |
7-8
pepsin activate pancreas |
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____ - enzymes from pancrease and bile salts from SI
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CCK
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____ - inhibiting and Insulin
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GIP
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____ - comes from the SI
It is responding to the presence of ____ products in the SI. See flowchart - food enters the SI, SI secretes ____ is the target tissue, will trigger the release of those ____, will help further the digestion process in the SI. ____ will also tell the gallbladder to please release bile, and ____ helps the ____ to relax and allow bile salts to enter the SI. |
CCK
food breakdown pancreas pancreatic enzymes CCK CCK sphincter of Oddi |
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Hormone - ____
____ receptors - found in the ____, the respond to the acidic chyme entering the SI, This _____ is synthesized by the ____. The ____ will enter the bloodstream and land on the pancreas (target organ). This triggers the release of the bicarb from the pancreas to neutralize the acidic chyme. Also there are some secretin receptors on the ____, and it will help inhibit stomach churning/gastric motility. And it will help inhibit further ____ secretion by the stomach. |
Secretin
secretin pancreas secretin SI secretin stomach HCl |
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____ - going in through mouth
____ - opposite |
Endoscopy
Colonoscopy |
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____ - way of looking at the lumen of the digestive system.
Can look at cell types, can look for ulcers, precancerous cells. |
Endoscopy
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____ - can be due to undercooked meat products, or food that sat too long and bacteria allowed to grow, bacteria not making us sick, but their toxins that they are releasing.
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Food poisoning
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Throw up a lot, can go into ____.
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metabolic alkalodosis
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Toxins can inhibit ____ by the large intestine, which ends up with that diarrhea. Some toxins can stimulate ____ into the lumen of the LI. (cholera is a good example, losing more water than they can take in)
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water reabsorption
active sodium transport |
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Occasionally the opposite can happen, reabsorbing too much water = ____, digestive motility slows down = too much time in the ____, and it keeps ____ water, not enough water to get that food product ____
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constipation
LI reabsorbing out |
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Between the SI and LI - called a ____ (a sphincter), again will contract and relax and allow small amounts of products from SI into the LI.
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ileocecal valve
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____ - main function is water reabsorption
Some of the fiber (complex carbs) (fruit pectin and plant cellulose) we do not have the enzymes to break it down, so it enters the ____. |
LI
LI |
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Large portion of the feces is ____ from the ____ (have a half life of like 2 days, lumenal epithelial cells) and some ____
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sloughed off cells
SI water |
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At the end of the ____, should have broken down all the proteins into their ____ and absorbed all these, digested fat into ____ and ____ and should have absorbed these, carbs all broken down to ____ and absorbed. Typically none of these should be sent to the ____.
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SI
amino acids monoglycerides, fatty acid chains glucose LI |
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Pancreas releases ____ and ____.
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insulin
glucogon |
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____ = basal metabolic rate
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BMR
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BMR =
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quiet, resting, fasting (no food in body) body breaks down nutrients to form energy/ATP
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Lots of things that affect BMR
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CHASEMP
Males have a faster BMR than females typically Certain hormones affect this thyroid hormone, growth hormone, testosterone = increase BMR AGE = the older slower your BMR Higher Body temperature will increase BMR Eating food will increase your BMR slightly Some of the nervous system NT (Nor and epinephrine )will increase BMR Pregnancy will increase BMR |
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____ will help -
Transport nutrients into the cells Other stuff, amino acids into the cells Once in the cells can help via a 2nd messenger system can help to break down that glucose to break down ATP |
Insulin
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If there is food present in the digestive tract (feasting) at some point _____ will be released by the ____ (GIP) ____ will act to ____ incorporated into the cell membranes
So ____ will help transport ____ out of the blood and into the ____. |
insulin
pancreas insulin increase glucose transporters insulin insulin cells |
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Fasting (have not eaten in a while) ____ should not be present, the longer I go w/o food the lower my ____ levels will drop, body will not let it drop to 0 (under normal circumstances)
Under fasting circumstances will release an antagonistic hormone - ____ - will help to increase ____ levels, can do this by releasing ____ from the liver (glycogenlysis) can trigger liver to produce ____ (gluconeogenesis) from fatty acids |
insulin
blood glucose glucagon blood glucose glucose glucose |
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____ release glucagon
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Pancreatic alpha cells
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____ release insulin
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Pancreatic beta cells
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I eat and ____ levels increase, pancreas releases ____,
Will trigger fat and muscle and liver cells to take up ____ and use them and then ____ levels will drop to a normal range. |
glucose
insulin glucose plasma glucose |
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Remember one of the functions of GIP - ____
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trigger release of insulin
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When glucose levels are low, ____ is released and, ____ will trigger the release of ____ back into the blood.
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glucagon
glucagon glucose |
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Insulin Disorders
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1. Type 1 diabetes mellitus
2. Type 2 diabetes mellitus 3. Gestational diabetes |
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Body temperatures tend to ____ and ____ throughout the day-
As you increase activity and the day goes on the ____ (at most ____) As nighttime sets in our body temp ____ and ____ starts to drop. |
increase
decrease temp increases 1 degree drops metabolic rate |
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____ = seems to negatively affect insulin receptors
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TNFα
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____ = decrease appetite at the hypothalumus
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Leptin
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Pathway of uncontrolled/unmonitored problem:
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Higher and higher blood glucose levels = start dumping the glucose in the urine, renal filtration of glucose - (acts like an osmotic solute) therefore will have an increased urine output
Will have a drop in plasma volume - drop in water and sodium and drop in blood pressure Will continue with the blood pressure drop until you are not getting enough oxygen to your brain |
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Some _____ we eat - we just excrete in the feces
Some of the _____ - we convert to ____ to synthesize steroid hormones, can incorporate into plasma membranes Some that we eat - ends up as the ____ that eventually clog our blood vessels We can use some of this cholesterol for good, ____ is not good. |
dietary cholesterol
dietary cholesterol plasma cholesterol lipoproteins too much |
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Also secrete -___ - the more fat cells you have the more you have, it seems to be linked to ____,
Studies trying to use it as a ____, if they have a lot are they about to enter a ____ phase of type 2 diabetes Seems to act on insulin receptors and changes them ____ or changes their ____ to insulin. |
Tumor necrosis factor Alpha (TNFα)
type 2 diabetes marker insulin resistant structurally receptiveness |
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Fat cells/adipocytes - secrete ___ (a protein),
____ helps regulate hunger at the ____ When ____ is released it signals the _____ that I am full. So in theory the more fat cells I have, the more ____ I secrete so I will say I am full and have adequate fat storage. Fatter people have ____ to ____ |
leptin
leptin hypothalamus leptin hypothalamus fat cells leptin target tissue resistance leptin |
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Cholesterol synthesis by the liver is ____ when ____ is decreased and vice versa.
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up-regulated
dietary cholesterol |
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w/ type 2 diabetes or gestational Diabetes
This does not work right, not an easy ____ (____ does not fall and ____ does not fall) |
negative feedback cycle
glucose insulin |
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Pathway of uncontrolled/unmonitored problem
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Higher and higher blood glucose levels = start dumping the glucose in the urine, renal filtration of glucose - (acts like an osmotic solute) therefore will have an increased urine output
Will have a drop in plasma volume - drop in water and sodium and drop in blood pressure Will continue with the blood pressure drop until you are not getting enough oxygen to your brain |
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Type 2 - (sometimes non-insulin dependent diabetes)
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Used to be called adult onset, but not because people are getting it younger and younger
Close to 90% of all diabetes sufferers Also have high blood glucose levels Their beta cells work fine, they are pumping out the insulin, often even have higher than normal insulin levels - but their target tissues have lost their response to insulin "target tissue resistant" Also seems to have a genetic tendency, but no actual gene that they can find Also has a tendency to occur in people that have higher weight/overweight Insulin does not really help much (they already have a lot) Need to monitor blood glucose levels (like type 1) Need to monitor what they eat (no cotton candy for breakfast) Increase activity level, esp if overweight, - two fold benefit will increase their metabolism (help drop weight) but also have shown that increasing exercise/activity will increase glucose transporters to incorporate into target tissue |
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Type 1 -
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person does not have enough, or no insulin in response to high blood glucose levels, so this person has difficulty absorbing glucose into their cells
Approximately 10% of people with diabetes have type 1 There does seem to be a genetic tendency (have not found a specific gene) but more likely to get it if someone in your family has it Seems to have an environmental trigger Shows up in children, or ppl in puberty/adolescence Will have high blood glucose levels, esp if not checked regularly Need to monitor those blood glucose levels If they receive insulin they can control it Have to watch their diet amount of sugar |
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Gestational diabetes -
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in about 10% of all pregnancies
Most of the time 95%, it goes away when she is done being pregnant It will look clinically like type 2 diabetes, still have functional pancreas, beta cells are still secreting insulin, but tissues have become resistant (to insulin) target tissue resistancy The reason - body will shunt nutrients preferentially to the developing baby (baby gets first dibs, and leave you the rest) Body changes its responsiveness to glucose temporarily. Typically test in that early 3rd trimester Have to drink a nasty orange "sugar" drink. Will test your responsiveness to "sugar bolus", when handle a big dose of sugar right typically have a negative feedback cycle (blood glucose rises, insulin rises, blood glucose falls, insulin drops) (a few hours) |
