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102 Cards in this Set
- Front
- Back
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what kind of things does our digestive system absorbe? |
Macronutrients (carbohydrates, lipids and protein) nutrients that provide energy by being broken apart to make ATP |
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what do Micronutrients do in digestive system? |
needed in smaller amounts such as -vitamins -minerals -water major function of vitamins and minerals are the fit with enzymes as coenzymes thats gonna help enzyme to better attach to substrate and speed up reaction, also assist catalazing reactions |
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what does stomach absorb? |
alcohol, asprin, caffeine and some other drugs |
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what does small intestine absorb? |
almost all vitamins, minerals & all carbs, lipids and proteins as well as over 90% of water |
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what does large intestine absorb? |
most of remaining water and few vitamines like, biotin & vitamin K |
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what are the digestive organs that food passes through? |
food enters.. -mouth -esophagus -stomach -small intestine -large intestine -rectum -waste exits through anus |
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what happens during Ingestion? |
food and water enters throguh mouth |
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what is the digestive processes? |
1-Ingestion 2-Propulsion 3-Mechanical Digestion 4-chamical digestion 5-Absorption 6-Defecation |
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what happens during propulsion? |
moving food through organs to next location (2 types) 1- peristalsis 2-segmentation |
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what does peristalsis do during propulsion? |
smooth muscle squeezes food through like toothpast through a tube(happens in esophagus, stomach, small & large intestines |
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what happens during segmentation in propulsion? |
food is squished in multiple locations back & forth but mostly forward, this mixes food in addition to moving it forward (mostly happens in small intestines ) |
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waht does Mechanical digestion do? |
food is physically broke up into smaller pieces -teeth do this in the mouth & trning of stomach also helps segmentation also happens here |
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what helps with digestion but dont directly come in contact with food? |
Accessory structures |
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what happens during Accessory structures? |
-salivary glands produce saliva to moisten food -contain amylase and lysozyme (kills some bacteria) -pacreas=produces most of difestive enzymes & secretes them into small intestines -liver=makes bile to break fats, stores nutrients & detoxifies poisons -Gallbladder=stores & releases bile made by liver |
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what does chemical digestion do? |
enzymes breaks food intosmaller pieces into nutrients by breaking bonds - mostly happens in small intestine with a little in mouth & stomach |
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what happens during Absorption? |
cells line lumen of small intestines absorb nutrients enter blood or lymph(absorb fat) -carbs & proteins will go into blood mainly -lipis (fats) will mainly go into lymph (lacteils) |
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what role does Defecation play in digestion? |
waste products (feces) exit body at anus -undigested materials such as fiber from food |
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what is the major functions/purpose of digestive system? |
Get nutrients into blood where cell's can use them for cellular respiration to make ATP |
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what are the layers of the GI tract walls? |
-Mucosa -Submucosa -Muscularis -Serosa |
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what is digestive system a big part of? |
Metabolism |
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Define Metabolism |
Total of all chemical reactions that occur in body, biggest one is cellular respirtion (type of catabolic reaction) |
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What is Catabolism? |
breaks things down -energy releasing process by which larger molecules are broken down into smaller ones -smarts in digestion; ends in cells with cellular respiration -energy released can power Anabolic reactions |
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what is Anabolism? |
putting things together -energy requiring process by which small molecules are joined to form larger ones -occurs in all cells as they "function" (mitosis) |
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what enzyme digest starch? |
Amylase |
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what is inside the lobes of the liver? |
microscopic lobules which are shaped like hexagons |
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whats on the edge of livers lobules? |
arterioles, venules and bile ducts |
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whats in the center of livers lobules ? |
center vein |
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what are most of liver lobules have? |
Hepatocytes (liver cells) with sinusoid capillaries gooing through |
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How to nutrients get to venules at the edge of lobules? |
Hepatic poetal vein carries nutrients to venules |
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After nutrients get to the venules in lobules where do they go next? |
go through sinusoid capillaries -nutrients and other substances are filtered out of these capillaries & stored by the hepatocytes which also detoxify poison (have alot of smooth ER to do this) |
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what do Hepatocytes in liver do with nutriens after they detoxify them ? |
Release some nutrients back into capillaries as body needs them. They flow into central vein, which leads to hepatic veins which flow into vena cava & back to heart/ general circulation |
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what is the first step of Carbohydrates absorption and digestion ? |
1. chemical digestion starts in mouth with salivary amylase (which gets denatured in stomach by acid) |
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what is second step of Carbohydrates absorption and digestion? |
pancreactic amylase continues digesting starch in smaller intestine breaking carbs into -Oligosaccharides (3-4 sugars) -disaccharides (2 sugars) |
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3rd step of Carbohydrates absorption and digestion? |
Brush border enzymes in columnar cell's membrne break (oligosaccharides & disaccharides ) into monosaccharides(Galactose, Glucose, Fructose) |
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4th step of carbohydrates absorption and digestion? |
cotransporter brings monosaccharides into columnar cell's with sodium ions (Na+) -all monosaccharides leave epithelial cells via facilitated diffusion enter capillary blood villi & mesenteric vein take them to hepatic portal vein & then liver |
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What is the 1st step in absorption and digestion of lipids? |
segmentation in small intenstins breaks lipids into small "globs" |
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what is the second step of lipid absorption and digestion ? |
Bile coats the globs of lipids pieces so they dont fuce back together (gets unemusified) |
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what is the 3rd and 4th step of lipid digestion and absorption? |
-Pancreatic lipase surrounds the pieces & breaks triglycerides into monoglycerides & fatty acids -Bile coates these smaller pieces so they dont fuse back together; coated monoglycerides & fatty acids are called=micelles |
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what does Micelles do in lipid? |
-go into cells by simple diffusion (they're nonpolar so they dont need transport proteins) -cells put them in vesicles called chylomicrons, which are exocytosed into lacteals |
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what is the 1st step of proteins Absorption and digestion ? |
chemical igestion starts in stomach with pepsin to break proteins into peptides (chains of amino acids) |
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what is the 2nd step of proteins absorption and digestion ? |
Trypsin from pancreas coninues digesting peptides into smaller onces in the duodenum |
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what is the 3rd step of proteins absorption and digestion? |
Brush border enzymes breaks peptides into individual amino acids or some chians of 2 or 3 |
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what is the 4th step of proteins of absorption and digestion? |
cotransporter brings amino acids into columnar cells with sodium ions (Na+) |
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How do amino acids get to liver? |
use different transport proteins to do facilitated diffution from cells into blood. -Mesenteric veins take them to hepatic portal veins & then to liver |
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what the deepest layer of GI tract wall that touches lumen? |
Mucosa=inner surface is simple columnar epithelium -absorbed nutrients pass through columnar cells & into blood |
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what does Mucosa have that helps protect cells from stomach acid & digestive enzymes? |
has muscou gland including goblet cells |
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what does digestive enzyme break up? |
-carbs -lipids -proteins which are in living cells |
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what causes folds in mucosa to increase, surface area for digestion & absorption ? |
outer edge of smooth muscle called=muscularis mucosa |
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what does submucosa contain? |
just external to mucosa -arteries & arterioles which supply O2 to cell's -venules & veins, which return deoxygenated blood & carry absorbed nutrients to liver -sensory nerves which sense fullness, stretch, pain, & motor nerves which control smooth muscle -lacteals-lymph vessels that carry absorbed fats |
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what is extternal to submucosa of GI tract walls? |
Muscularis |
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what is the circular layer of Muscularis? |
smooth muscle with cells oriented perpendicular to length of GI tract -contacying these squeezes thte lumen closer together like a value |
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what is longitudinal layer of Muscularis? |
smooth muscle with cells oriented parrallel to length of GI tract -contracting these inches the tubes contents forwards insides the organ |
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what is most superficial layer of GI tract wall ? |
serosa=visceral peritoneum -the serous membrane (made of simple squomous epithelium) that surrounds organs |
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what is Mesenteries of Serosa? |
parts of serous memebrane wrap around organ & form flat sheets that attach organs to each other & to body wall (flat sheets= sous membrane & arteries, veins, nerves, lymph vessels) |
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what happens n the mouth during digestion? |
-teeth break up food mechanically -3 types of salivary glands produce saliva to moisten food -saliva contains amylase (starch break down into simple sugars) -saliva also contains Lysozyme (kills some bacteria) -food compacted into bolus (bite thats swallowed) |
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what happens in Esophagus during digestion? |
soft muscular tube, takes few seconds for bolus food to move through into stomach by peristalsis & gravity |
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How does food get into stomach from esophagus? |
-Lower esophageal sphincter opens to let food into stomach then closes -if sphincter doesnt close all the way, chyme (food mixed with stomach acid) can go bck up esophagus, causing acid reflux (heartburn) |
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If a person has frequent heartburn what can happen? |
can cause Gastroesophageal reflex disease -can start to eat through walls of esophagus & sometimes cause ulcers |
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Describe stomach? |
-has extra layer of smooth muscle -very muscular -has muscular folds on inside (rugae)= helps turn food - has extra layer of muscularis (oblique layaer)= allows it to turn back & forth to mix food with HCL forming chyme (mechanical digestion) -releases food little at a time through=pyloric sphincter |
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what does Pyloric sphincter do? |
gradually opens & closes to allow small amounts of chyme into duodenum, giving it time to neutralize acid & digest & absorb food |
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what activates stomach & makes more HCL? |
cells inside stomach release hormones called =Gastrin -It absorbes alcohol (causes people to get drunk fast) |
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what does Mucosa layer have that between rugae? |
Gastric pits= contain certain important cells (4 types) 1-Mucous neck cells 2- Parietal cells 3- Enteroendocrine cells 4- Chief cells |
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Describe Mucous neck cells? |
simple columnar epithelium near top of pit. Makes thick, acidic mucous -replaced frequently due to damage from stomach acid |
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Describe Parietal cell |
makes HCL acid and intrinsic factor |
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what denatures bacteria & activates pepsinogen turning it into pepsin? |
HCL |
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whats the most important thing stomach does for homeostasis? |
Producing Intrinsic factor |
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what does Intrinsic factor do in parietal cells? |
binds to vitamin B12 in food is not absorbed it can cause pernicious anemia= causes nerve damage if not treated |
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If we didnt have a stomach where else can acid denaturing bacterial enzymes happen? |
in small intestine, can live without stomach |
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what are volunatry digestion actions? |
-Initiation of swallowing -External anal sphincter open to allow waste to exit |
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what things are Involuntary digestion actions? |
-End of swallowing -Internal anal sphincter opens at the same time as External sphincter |
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what is stomach mainly controled with? |
both sympathetic & parasympathetic nervous system -parasympathetic will activate stomach -sympathetic will inhibit stomach -Gastic also stimulates stomach 3 different types of phases(cephalic, Gastric, Intestinal) |
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Describe Cephalic Phase-stimulation? |
Head controls stomach -seeing/thinking about food(cerebral cortex) -tasting/smelling food receptor( hypothalamus/ medulla) causes vegus nerve (part of parasympathetic) to activate stomach |
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what is Cephalic phase- Inhibition? |
Seeing, smelling or tasting gross things & depression inhibits stomach -happens in cerebral cortex -inhibits parasympathetic & stimulate sympathetic & inhibits stomach |
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Describe Gastric phase-stimulation? |
Stomach controls stomach -stretching of stomach, food chemicals (pepetides & caffeine) & if pH is high goign to cause us to release gastrin from stomach & activate it= make more HCL & turn back & forth more |
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Describe Gastric phase- Inhibits? |
stomach with to much acidic pH less than 2 or emotional distress will inhibit stomach |
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Describe Intestinal phase? |
Duodenum controls stomach -when food starts coming into duodenum its going to presence acidic pH, food chemical (fats, proteins) & very briefly stimulate stomach but afterwards inhibits it so food moves nto intestines slowly |
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what are the 3 parts of Small Intestines? |
1- Duodenum 2- Jejunm 3- Ileum |
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what the most important organ for digestine and absorption? |
small intestine absorbes=carb, lipids, proteins, water, vitamins, minerals & ions -has slightly basic pH & most of enzymes that chemicall digest food (amylases, lipases & trypsin)-made in pancreas |
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what does Amylases do in small intestine? |
breaks down more starch |
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what breaks down lipids in small Intestine? |
Lipases |
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what breaks down proteins in small intestine? |
Trypsin=proteins get broken down in stomach by pepsin but they get denatured once Ph get changed in small intestine |
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what % of bodys blood feeds digestive organs? |
about 25% |
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what do Hepatocytes do as blood passes through the lobules of liver? |
can filter out toxic substances & store vitamins, minerals (iron, glucogen & others) |
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what helps increase blood flow to digestive organs & activate muscle contraction to move food through? |
parasymphathetic nervous system |
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what does large intestine (colon) do? |
whatever is not absorbed in small intestine passes through Ileocecal valve to large intestine= it absorbes more water, compacting waste to make it solid |
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what does large intestine contain that digest & absorbe foods that our own enzymes cannot & may produce smelly gases as byproducts (farts)? |
Microbiota =recent topic of study diets/ mothers diet during pregnancy can influence microbiota |
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what do some microbiota make? |
vitamins like biotin & vitamin K which can be absorbed through large intestine wall |
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what is probiotics? |
"good" bacteria is supplements or things you eat that may colonize large intenstine, found in fermented foods like(yogurt, kimchi) |
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what are Prebiotics? |
Foods that we cant digest but that the good bacteria can eat |
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How to promore healthy bacteria? |
Plant-based diet |
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A diverse microbiota reduces risk of things like what? |
allergies * autoimmune disease |
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what do circular folds contain? |
villi-smallar folds look like finger and microvilli folds in cell membrane of individuals simple columnar cells |
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what causes release of CCK? |
presence of food chemicals in small intestine |
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what does CCK do? |
-hormone which travels to pancreas & makes it release enzymes-rich juice into duedenum -also causes liver to make more bile & release it form gallbladder (bile helps break fats) |
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what casues releaes of Secretin in samll Intestine ? |
presence of acid in small intestine |
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what is secretin do in small intestine? |
hormone which travels to pancreas & makes it release bicarbonate-rich juice into duodenum -bicarbonate can be a weak base & help neutralize acid, the pH of small intestine is around 8 |
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where are most digestie enzymes made and released into what? |
-made in pancrea -released into duodenum |
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Typsin breaks what? |
proteins |
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what would inhibit stomach's secretory activity? |
long term stretching of deudenum |
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If a person was missing Parietal cell what can they get? |
Pernicious anemia |
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what contributes to mechanical digestion? |
-rugae -teeth -segmentation |
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Area where chyme, pancreactic juices and bile meet and mix? |
Duodenum |
