Explore Your Digestive System: Hands-On Lab Activity
School
William Rainey Harper College**We aren't endorsed by this school
Course
BIO 135
Subject
Biology
Date
Dec 12, 2024
Pages
7
Uploaded by GeneralBeaver1157
S437Name: ________________________________________ Period: ______All About the Digestive System LabObjectives: By the end of the lab you should be able to answer the following questions:1.How long is your gastrointestinal tract in total?2.How long is each organ individually?3.How does each organ impact food?Part 1: How long is your gastrointestinal tract?From the moment you eat your meal to the moment you eliminate thewaste left over from that meal, your food goes on an epically long journey. Thegastrointestinal tractis one long tube ofmany organs starting at your mouth and ending at your anus which your food passes through. Some of these organs dochemical digestion(break down food with enzymes and acids), some domechanical digestion(break down food byforce), and some completeabsorption(remove essential nutrients from food).Just how long is the GI tract?In thisportion of the lab, you are going to create a yarn model of your gastrointestinal tract. You will measure and cut yarn to bethe approximate length of each GI tract organ and then tie those pieces of yarn together to form one long “tract.” Let’ssee how long it is!1.Themouthis the first part of the gastrointestinal tract. You chew each bite of food for approximately 10 seconds.To measure your mouth, hold a piece ofred yarnat the front of your lips and stretch it along your cheekto your earlobe. Cut the piece of yarn with ONE EXTRA INCH. Using a ruler or meter stick, measure thelength of the yarn and subtract one inch.Record the length of your mouth in inches on the data tableabove.Using masking tape, put a label on theredpiece of yarn that says “mouth.”2.Next, food enters yourpharynx. The pharynx splits into two tubes: the esophagus & the trachea. The trachealeads to the lungs and isnotpart of the gastrointestinal tract. Theesophagusis a muscular tube which pushesfood to the stomach. It takes food approximately 6 seconds to be pushed down your esophagus.in10sec13in6secUhr132inSur66in36hrs230in45hr16sec
To measure the length of the pharynx and esophagus together, get a piece ofyellow yarn. String theyarn from your earlobe to your xiphoid process (bottom of your sternum). Cut the piece of yarn withONE EXTRA INCH. Measure the length of the yarn and subtract one inch.Record the length of yourpharynx and esophagus in inches on the data table above.Using masking tape, put a label on theyellowpiece of yarn that says “pharynx & esophagus.” Tie thepiece of yellow yarn to the end of the red piece of yarn. Try to use a very small amount of string to tiethe knot.3.Your esophagus pushes food into yourstomach. Your stomach is about 12 inches long when it is empty. Cut apiece ofgreenyarn to be 13 inches long. Tie the green piece of yarn to the end of the yellow piece of yarn.Using masking tape, put a label on thegreenpiece of yarn that says “stomach.”4.Food remains in your stomach for around 4 hours as it is slowly and gradually dumped into yoursmall intestine.No doubt about it - the small intestine is the longest part of your gastrointestinal tract! It coils and folds manytimes to fit inside your abdomen.To estimate the length of your small intestine, measure your height in inches and multiply it by two.Record the estimated length of your small intestine in inches on the data table above. Using a ruler ormeter stick as a guide, cut a piece ofblueyarn to represent the small intestine (with one extra inch). Tiethe blue piece of yarn to the end of the green piece of yarn.Using masking tape, put a label on thebluepiece of yarn that says “small intestine.”5.After digested food spends around 5 hours in the small intestine, it passes into thelarge intestine. The largeintestine’s name can be deceiving. It is wider than the small intestine, but it is significantly shorter! Digested foodtravelsveryslowly through your large intestine. The amount of time that food spends in this part of the tractvaries based on the type of food and other factors, but on average food is in your large intestine for 36 hours!If we removed your large intestine and stretched it out, it would measure very close to your body height!Using the height you measured in step #4, record the estimated length of your large intestine in incheson the data table above. Measure apurplepiece of yarn to be your height. Cut it with one extra inch. Tiethe purple piece of yarn to the end of the blue piece of yarn.Using masking tape, put a label on thepurplepiece of yarn that says “large intestine.”6.The large intestine ends with therectum(the last part of the large intestine) andanus. Total up the length of andtime spent in your gastrointestinal tract in the data table on page 1.7.Math time! Take the number of inches that you totaled up on the table and convert it to the length of yourgastrointestinal tract infeet.The length of your digestive tract is ______________ feet.8.Take your completed gastrointestinal tract and spread it out in the hallway. Is it longer or shorter than youexpected?
Part 2: How does each organ impact food?In this part of the lab, you will simulate the effects of digestion on the foodwe ingest. You will putreal foodthrough a series of steps to demonstrate the action of each digestive organ on our food.This activity works best in a small group.Supplies needed:one plastic bag filled with¼ cup of cereala second empty plasticbag; a permanent markerone 10-mL syringe orgraduated cylinder50 mL waterlemon juice or vinegaryellow food coloringgreen food coloringa paper towel rolla spongeMouth:1.Use the permanent marker to label the plastic bag with cereal as “mouth.”The mouth is a site of both chemical and mechanical digestion.2.Discussthe parts of the mouth that help with the mechanical digestion offood.3.Teeth are an important part of mechanical digestion. Using yourphone/iPad camera or a mirror, count how many teeth you have. Howmany teeth do you have? _______4.You have four main types of teeth. This diagram shows each type. Whichtype of teeth do you think would be best at each job when eating?a.Grinding up vegetables in a salad:__________________________________b.Biting into a carrot: ___________________c.Chewing gum: ______________________d.Tearing into meat: ___________________5.The mouth is also an important part of chemical digestion. You have 3pairs of salivary glands that produce saliva. Saliva is 99.5% water butalso contains some important enzymes, such as salivary amylasewhich breaks down starchy foods like potatoes and bread.6.To simulate the action of your salivary glands, add 10 mL of water toyour bag of cereal. The water represents saliva. Close the bag so thereis no leaking. Have each member of the group mush the cereal tosimulate chewing. Continue until the food is ground up.7.How did the “saliva” and “chewing” change the contents of your bag?________________________________________________________________________________________________________________________________________________________________________________________
____________________________________________________________________________________________Esophagus: No chemical or mechanical digestion occurs in the esophagus, but this muscular tube is an importantpathway between the throat (pharynx) and the stomach.1.Prepare your second plastic bag and use the marker to label it “stomach.”Open the bag.2.Your esophagus has two sphincter muscles within it. One sphincter is at thetop and one is at the bottom.a.Theupper esophageal sphincteropens to let food into theesophagus.b.Thelower esophageal sphincteropens to allow food to pass intothe stomach. Label each sphincter on the picture to the right.3.Make a small snip in the corner of the “mouth” bag of digested cereal andattempt to squeeze the cereal mixture from the mouth bag into the stomachbag. The small snip represents your esophagus.4.Did the mixture pass easily through the cut in the corner of the bag or did youhave to push it through? ___________________________________________5.Our esophagus contracts to cause food topushto the stomach. Watch avideo of the esophagus contracting. What are these muscle contractionscalled? _________________________________________________________6.Which type of muscle tissue is the esophagus? ______________________________________________________7.Are the contractions of the esophagus voluntary or involuntary? ________________________________________8.If peristalsis is what causes food to travel through the esophagus, can food travel through your esophagus to yourstomach while you are lying down? Why? ______________________________________________________________________________________________________________________________________________________9.If a person has acid reflux, stomach acid regurgitates into the esophagus, causing burning and pain. Whichsphincter is failing if someone has acid reflux?___________________________________________________________________________________________________________________________________________________Stomach:1.Once all the cereal mixture has been pushed into the stomach bag, add 25 mL of water, one squirt of lemon juiceor vinegar, and 3 drops of yellow food coloring to your stomach bag.a.This water, juice, and food coloring represent a fluid that your stomach produces known asgastric fluid.Gastric fluid is responsible for ___________________ (chemical or mechanical) digestion. The stomach isalso made of smooth muscle and contracts every 15 to 25 seconds.b.These contractions that the stomach uses to churn food are an example of ________________________(chemical or mechanical) digestion.
2.Close the bag tightly and let each group member churn it around for 15 seconds.3.How did the “food” change in the stomach? ______________________________________________________________________________________________4.The stomach is mainly responsible for chemical and mechanical digestion, but asmall amount of absorption happens in the stomach as well. Open the lid ofthe “stomach” bag and pour a very small amount of water out onto the old“mouth” bag to simulate absorption.5.Close the “stomach” bag and throw the old “mouth” bag away.6.Some substances are absorbed in your stomach, such as medicine, alcohol, andwater. Think about taking a pill for a headache or cramps. How long does it take for that medicine to work? Whydoes it make sense that absorption of certain medicines happens in the stomach and not the small intestine?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________7.How long will this food stay in the stomach? _______________________________________________________Does your “food” look the same as when it first entered the stomach? __________________________________8.Because the food has changed so much, we now call it by a new name! Food and gastric fluids that leave thestomach are known aschyme. Which organ are we in where food changes from food to chyme? _____________Small Intestine: The small intestine secretes intestinal fluid, a fluid-filled withenzymes. Add one drop of green food coloring to the bag to represent intestinalfluid. Mix the intestinal fluid and chyme around in the bag. Prepare your papertowel roll! Using a permanent marker, label the roll as “small intestine.”1.The paper towel roll represents the small intestine. Have one member ofthe group hold the paper towel roll at a slight angle over a beaker. Pour allof the cereal mixture from the “stomach” bag into the top of the papertowel roll. Tilt the paper towel roll back and forth slightly as the foodmixture rolls back and forth through it.2.The small intestine is responsible for the absorption of nutrients and water. How did this part of the lab simulatethe function of the small intestine? ___________________________________________________________________________________________________________________________________________________________3.When you tilted the paper towel roll back and forward slightly, you were simulating the ____________________(chemical or mechanical) digestion that occurs in the small intestine. Our small intestine pushes food back andforth within itself to further digestion and mix food with intestinal fluid. These back-and-forth motions arecaused by smooth muscles and are known assegmentations. They are different than peristalsis because they donot push food forward through the digestive tract.
4.What is the difference between segmentations and peristalsis? ____________________________________________________________________________________________________________________________________5.Which happens in the small intestine? Circle all that apply:Mechanical digestionChemical digestionAbsorption6.Push the cereal mixture that settled in the tube back into the stomach bag. Cross off the word “stomach” andreplace it with the term, “large intestine.”Large Intestine:1.The sponge represents the large intestine. Put the sponge into the bag and absorb asmuch liquid as you can. You may need to make several trips to the sink to rinse yoursponge out. Continue squeezing the sponge and the chyme mixture together until mostliquid is absorbed.2.Why is a sponge a good representation of the action of the large intestine?________________________________________________________________________________________________________________________________________________________________________________________Anus:1.Cut a small hole in the corner of your large intestine bag.2.Simulate defecation by pushing the remaining digested chyme into the trash can.Part 2 Conclusion Questions:1.The liver, pancreas, and gallbladder are also a part of your digestive system. Why didn’t we discuss them intoday’s lab? _____________________________________________________________________________________________________________________________________________________________________________2.Use what you learned in part 2 to answer this question: Which organs in the gastrointestinal tract are responsiblefor chemical digestion, mechanical digestion, or absorption? Put a checkmark for each box that applies! You canhave multiple check marks per organ!OrganChemical DigestionMechanical DigestionAbsorptionMouthPharynxEsophagusStomachSmall intestineLarge intestine
OrganLength of Each Organ (inches)Time in Each OrganMouthPharynx & EsophagusStomach12 inchesSmall intestineLarge intestineAnusN/AN/ATotal