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biology-digestive system

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What are the 3 main parts in digestion?
Digestion,absorption and elimination.
what happens in diegestion?
mechanical and chemical breakdown of indigested food into molecules.
what happens in absorption?
passage of digested materials from gut into blood or lymph.
what happens in elimination?
its the expulsion of indigestiable food.
what are the organs of digestion?
Mouth, esophugus, stomach, small intesine, large intestine and anus.
what parts aid in digestion but are not found in the gut?
pancreas,liver and gall bladder.
what is mechanical digestion?
teeth tear appart and chew food .
what is chemical digestion?
enzymes break down macromolecules
what does saliva contain?
water, mucus and salivary amylase.
what does salivary amylase break down? Where is it made?
starch, made bey salivary glands.
what the equation for salivary amylase?
starch + h20 -------salivary amylase--> maltose
waht is food called after its been chewed up?
bolus
How do we swallow?
1. the soft palate moves back to cover the opening to the nose. 2. the epiglottis covers the opening to the trachea. 3. bolus enters esophugus.
what is the esophagus and where is it located?
its a long muscular tube which extends from pharynx to stomach.
what is the process by which food moves down the esophagus?
Peristalsis
what allows food to enter the stomach once the food reaches the end of the esophagus?
cardiac sphincter
how many layers of muscle does the stomach have?
3
the precense of peptides causes what?
causes cells in the stomach to secrete gastric juice
what does pepsin act on? what is it produced by? what is the ph?
produced by gastric glands acts on stomach ph:acidic
what happens when pepsinogen and hcl combine?
pepsinogen changes to pepsin
what is the stomach ph?
2-3 very acidic
why doesnt the stomach digest itself?
secreted by mucosal protect inner wall
what would happen if the acid broke through the protective mucas?
ulcer, pepsin digest lining of stomach
what opens to release food from the stomach into the duodenum?
polyric sphincter
what is food called after it leaves the stomach? hint not bolus
acid chyme
where does most of the absorption of nutrients take place?
small intestine
what does the presence of acid chyme in the duodenum do? 2 things
1. stimulates pancrease to release pancreatic juice. 2. stimulates liver to produce bile
where is bile stored?
gall bladder
what sdoes pancreatic juice contain?
sodium bicarbonate enzymes
what is sodium bicarbonate and what does it do?
its a base, it neuteralizes acid chyme
what are the four enzymes in pancreatic juice?
Pancreatic amylase, trypin, lipase and nuclease
what is the equuation for pepsin?
Protien +h2o --> peptides
what is the equation for pancreatic amylase?
Starch+h20----------> maltose
where is salivary amylase produced and what does it act on? what is its pH?
its produced by salivary glands it acts on mouth ph:nuteral
where is it pdouced ? what does it act on? its ph?
its produced by the pancreas it acts on the small intestine ph:basic
what is the ph enymes in pancreatic juice work in ?
8-9
from what part does bile enter the duodenum?
common bile duct
what is bile?
empulsifying agent.
what does the rest of the small intestine function for?
the chemical digestion and absorption of nutirents.
the wall of the small intestine secrets what 3 enzymes to further digest food ?
1. Peptidase 2.Maltase 3.Lactase
what is the equation for Maltase?
Maltose+h20----> glucose + glucose
what is it produced by? what does it act on? what is its ph?
its produced by smallintestine acts on small intestine ph: basic
why is there alot of small intestine?
because every nutrient is absorbed throgh the walls
how is the small intestine adapted to absorb lots of nutirents?
1) Intestinal wall is convoluted to surface ares. 2) villi increase surface area for nutriens absorption. 3) microvilli increase the surface area for nutrient absorption 4) lenght of the surface area allows time for nutrient absorption.
what are the livers six main functions?
1) Production of bile 2) production of blood proteins from amino acids 3) Produces urea from break down of amino acids 4) converts hemoglobin from old red blood cells to bile pigments. 5) detoxifys blood by removing and metabolizing posinious substances 6) store glucoes as glycogen after eating and breaks down glycogen to glucose to maintain the glucose concentration between meals.
what does the large intestine consist of ?
colon and rectum.
what are the functions of the large intestine?
absorbs water and salts stores undigestable material until it leaves the anus.
what are the three main parts of the large intestine?
ascending trasverse decending
what does bacteria do in the large intestine?
it helps break down nondigestable food and they produce some vitimins and amino acids.
whaere in the pacrease are hormone producing cells found?
islets of langerhans
what two hormones are produced by the pancreas?
1) insulin 2) glucagen
what do the cells in the pancreas do?
1) production of pancreatic juice 2) hormones
what are the main components of Gastrice juice?
Hcl, Renin, pepsinogen, Gelatinase, Gastric Amylase and Gastric lipase.
what is the anus?
its the external opening of the digestive system where waste is expelled.
what is the appendix?
its attached to the first portion of the large intestine has no funtion.
what is the acending colon?
part of the large intestine where food travels horozontally
what is the cardiac sphincter?
located at the top of the stomach, prevents food from going back up into the esophagus.
what is the commmon bile duct?
its a tube connecting the liver, gall bladder, and pancrese to small intestine. carrys bile from liver to small intestine.
what is the decending colon?
part of large inteste on left side.
what is the duodenum?
it breaks down food in small intestine. also regulates emptying of stomach via hormonal pathway. breaks down fat
what is the epiglottis?
when at rest the epiglottis aloows air to come in when swallowing it covers the entrance to the larynx ti prevent food and drink comming into the windpipe
what is the eopshgus?
muscular tube allows the movement of swallowed food from the pharynx to the stomach.
what is the gallbladder?
it stores bile
what is the ileum?
absorbs nutirents , bile absorbed here and returns to liver through blood vessels in the intestine walls.
what is the jejum?
where chemical break down of the food chyme is complete.
what is the mouth?
mouth recieves food , chews it, mostiens it and starts to digest it.
what is the pancrease?
makes pancreatic juice
what is the pyloric sphincter?
empties stomach fluids
what are salivary glands?
produce saliva.
What are the three salivary glands and where are they found?
paratid below ears sublingual tounge submandibular under jaw
what is the stomach?
three layered muscle that mixes and churns food it has mucus lining which contains gastric juice.
what are the four types of teeth and what are they used for?
1) eight inscisors -for biting 2)four canines -for tearing 3) eight promolars -for grinding 4) twelve molars for crushing
what is the transverse colon?
seperates the acending from the decending.
Where do glycerol and fatty acids go?
absorbesd across villi.
what is the funcion of the hepatic portal vein? how is it formed?
vein leading to the liver, formed by the merging of blood vessels leaving the small intestine.
Majority of digestion occurs here?
small intestine
what two organs produce secretions that end up in the duodenum?
Liver -bile Pancrease -gastric juice
why is bile green?
from the by products of hemglobin breakdown
what is the difference between digestion and absorption?
digestion _preotiens are broken down and it occurs in the gut. Absorption - its the digestion of nutrients from the gut lumen into th blood
Describe Perastalsis? How does a combination of circular and longditudal muscles cause this action?
Peristalsis is the rythmitical contractions of the esophogal muscles. when the food bolus reaches the end of the esophagus and arrives at the cardiac sphinter connecting to the stomach.
How does the stomachs structure relate to its function?
its related because it has an mucus lining and an acicic ph this helps it by killing bacteria and it breaks down food.
what is the equation for tripsin?
Protein+ h20---------> peptides
what does tripsin act on? where is it produced? ph?
produced pancrease act on small intestine ph:basic
what is the equation for peptidases?
peptide=h20----->amino acids
what is peptidase produced by? what does it act on? ph?
produced by small intestine act on small intestine ph:basic
what is the equation for Nuclease?
RNA and DNA+h20-----> nucleotides
what does nuclease act on? what is it produced by? ph?
produced Pancrease act small intestine ph:basic
what is the equation for nucleosidases?
Nucleotide+h20-----> base+ sugar + phosphate
what is it produced by? act on? Ph?
its produced by small intestine act on small intestine ph:basic
what is the equation for lipase?
fat droplet+ h20----------> glycerol + fatty acids
what is it produced by act on ph?
produced by pancres act on small intestine basic

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