Nutrition Ch 3: (The Basics of Digestion)

Secretions

*Chemical digestion* in the small intestine occurs as enzymes in intestinal _________s continue to break down nutrients to prepare them for absorption.

Triglyceride

A _____________e is an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid. Most are broken down in the small intestine with the help of another enzyme.

Bolus

A ______s (chewed mass of food) enters the pharynx and causes the swallowing reflex to kick in, and then you can no longer control the action.

Bolus

A ______s is a soft mass of chewed food. A term used to describe food after it has been chewed and mixed with saliva.

Cells

A. ______s are the basic building blocks of life. All vital processes take place within them. B. Those of similar structure and function combine to form *tissues.* C. Tissues combine to form *organs* which perform specialized functions. D. Organs work together in *organ systems* like the digestive system.

750

About ___ milliliters (about 3 cups) of unabsorbed residue enter the large intestine each day. This slow entry from small to large intestine enables body to maximize nutrient absoprtion.

Macronutrients

All ____________s -- carbs, fats + proteins -- are broken down into their component parts by their specific enzymes. Vitamins and minerals are absorbed intact.

Villi, brush border, microvilli

Anatomy of the Stomach: * The multifolded arrangement and ____i provides an immense surface area over which nutrients can be absorbed. * Blood and lymph vessels pick up nutrients through the ______h _______r and transport them throughout the body. * ________i on the surface of intestinal cells further increase the surface area.

Teaspoon

Approximately 1-5 milliliters (1 _______n) of chyme are released into the small intestine every 30 seconds during digestion.

Pyloric sphincter

As digestion continues, peristaltic contractions push the chyme toward the lower part of the stomach. As the chyme accumulates near the _______c ________r, the sphincter in the bottom of the stomach that separates the pylorus from the duodenum of the small intestine, relaxes and allows chyme to gradually enter the small intestine. This sphincter prevents chyme from exiting the stomach too soon, and it prevents intestinal contents from returning to the stomach.

Gastroesophageal reflux disease

Chronic heartburn and the reflux of stomach acids are symptoms of GERD, which stands for ___________l _______x __________e.

Absorption

Degestion is the forerunner to _________n. Once the nutrients have been completely broken down, they are ready to be used by cells of the body. In order to reach the cells, however, they have to leave the GI tract + move to the other parts of the body. So the nutrients are absorbed through the walls of the intestines and into the body's 2 transport system (circulatory + lymph). They are then taken to the liver for processing before moving on to their destination.

3, 10

Depending on the amount of food and the type of food consumed, the contact time in the small intestine is about _ to __ hours.

Nutrients

Digestion converts whole foods into individual ________s that can be used by the body's cells.

Polypeptides, triglycerides

Enzymes in the stomach, including pepsin and gastric lipase, begin breaking down protein into _____________s and a few _____________s into shorter-chain fatty acids.

Water

Flavors dissolved in _____r are quickly detected, but also quickly dissipated (disappears). Hence, why many prefer ice cream to frozen popsicles, or high-fat foods over low-fat.

10,000

Food scientists estimate that each of us has at least __,____ taste buds.

Carbohydrate

Foods high in ___________e exit the stomach faster, and therefore make you feel less full, than foods high in protein, fat, or fiber.

Gastrointestinal tract

GI = the _____________l _______t, the body area containing the organs of the digestive tract. It extends from the *mouth* to the *anus*.

Pepsin

Hydrochloric acid has many important digestive functions. It activates ______n, a digestive enzyme produced in the stomach that breaks down protein.

Chyme

In the stomach, the swallowed *bolus* of food soon becomes ______e, a semiliquid substance that contains digestive secretions plus the original food. A liquid combination of partially digested food, water, HCl and digestive enzymes. The stomach can expand to hold 2-4 liters of this substance.

Villus

Individual villi are called a ______s. Each of them are adjacent to a cluster of blood capillaries, lymph vessels, and nerve fibers. Covered in microvilli.

Faster

Low-calories foods exit the stomach *slower* or *faster* than concentrated, high-calorie foods because they require minimal digestion?

Sugar, salt, fat

Most humans have an innate preference for sweet, salty, and fatty foods. _____r seems to elicit universal pleasures, even with babies, and the brain seeks pleasure. ____t provides 2 important electrolytes (Sodium/Na and chloride/Cl) are essential to your body and can stimulate the appetite. High-___t foods not only have rich textures and aromas that round out the flavors of food, but also provide essential nutrients that are critical to your health.

Low

Most liquids, carbohydrates, and low-fiber foods require *low* or *high* digestive activity? Hint: Easier to absorb and have less surface area due to low fiber content.

Olfactory

Odor/smell processing cells are called ___________y cells. Processed by Cranial Nerve 1.

Pharynx

Once food has been adequately chewed, it's pushed to the back of the mouth and into the ______x by the tongue. This is the throat; passageway for the respiratory (air) and digestive tracts (food and beverages).

Lipase

Pancreatic enzyme necessary to digest fats is called gastric ________e.

Voluntary

Pushing chewed food to the pharynx is a voluntary or involuntary act? [Meaning, can you control it or not?]

1, 2

Soft foods and liquids pass through in about _ to _ seconds.

8

Solid or partially chewed food passes through the esophagus in about _ seconds.

Sucrose

Sugar is also called ________e and is broken down into fructose and flucose.

Gustatory

Taste cells are also called _______y cells.

23

The GI tract is a tube that is about __ feet long beginning with the mouth and ending with the anus. Stretched vertically, this is about as much as a 2-story building!

Lower esophageal sphincter

The LES stands for the _______r ______________l ___________r, a circular band of muscle between the esophagus and the stomach that opens and closes to allow food to enter the stomach. This is found at the bottom of the esophagus, at the narrow end just above the stomach.

Large

The _____ intestine absorbs water and some nutrients. Once the chyme has passed through the small intestine, it comes at the ileocecal spincter into here.

Large

The ______ intestine absorbs water, produces a few vitamins, absorbs important electrolytes, and forms and stores fecal matter. 5 feet long, 21/2 inches in diameter. It is NOT tightly coiled, has no villi or microvilli, and does not secrete or use digestive enzymes + hormones. Produces mucus to protect cells and be a lubricant for fecal matter.

Esophagus

The ____________s is the tube that extends from the throat to the stomach. The "digestive" pipe, as opposed to the respiratory pipe.

Ileocecal

The __________l sphincter serves as the gateway to the large intestine. Primary purpose: To prevent backflow of fecal contents from large intestine into the ileum. Quite strong! Resists reverse pressure.

Digestive

The _________e process is the breakdown of food into absorbable components using mechanical and chemical means. A multi-step process in which food is softened with moisture and heat, and then broken down into smaller particles by chewing and exposure to enzymes.

Stomach

The ________h is a muscular, digestive organ that continues mechanical digestion by churning and contracting to mix food with digestive juices. Holds food after it's moved down the esophagus + before it's propelled into small intestine. The food is continuously mixed for several hours. Has a role in chemical digestion because it produces powerful digestive secretion (HCl, various enzymes, mucus, intrinsic factor, and gastrin).

Small intestine

The ________l ___________e is a long, narrow, coiled chamber in the abdominal cavity. The first part of its name refers to the size of its diameter, not its length (20-24 feet of the GI tract). Consists of 3 segments: duodenum, jejunum, and ileum. Extends from the pyloric sphincter to the beginning of the large intestine. Most of the digestion and absorption of food occurs here.

Lumen

The ______n is the interior of the digestive tract, through which food passes. (The hole of the tube)

Pylorus

The ______s is the distal region of the stomach, opening to the duodenum. The narrow passage that connects the stomach with the small intestine.

Large intestine

The _____e ________e is the final organ of the GI tract. It consists of the cecum, appendix, colon and rectum.

10, 20

The average person has about __ million to __ million olfactory/odor cells.

2000, 4000

The average person is capable of distinguishing ____ to _____ aromas.

92, 97

The body is efficient at absorbibg nutrients. Under normal conditions, you digest and absorb __ to __ percent of the nutrients from your food. [More than 90%]

Circulatory, lymph

The body's 2 transport systems are the ________y system and the ______h systems.

Taste

The brain recognizes _____e in this manner: When food is consumed, portion of the food are dissolved in saliva. These fluids make contact with the tongue's surface. The taste cells send a message to the brain, and then the brain translates the nerve impulses into taste sensations that you recognize.

3, 5

The cell lining your GI tract have a very brief life span. They function for _ to _ days and are shed into the lumen/interior of the intestinal tract and are replaced with new healthy cells.

Bacteria

The chemical digestion in the large intestine is due to the efforts of _______a.

10, 8, 12

The first segment of the small intestine, the *duodenum* is about __ inches long. The second area, the *jejunum* is about _ feet long. The final region, the *ileum* is about __ feet long.

Circular

The lining of the small intestine is also arranged in unique _______r folds which further increase the absorptive surface area. These folds cause the chyme to spiral forward through the small intestine rather merely move in a straight line.

GI tract

The main role of the __ ______t is: 1. To break food down into its smallest components. 2. Absorb the nutrients. 3. Prevent microorganisms or other harmful compounds consumed with food from entering the tissues of the body.

GI

The main roles of the __ tract are to: 1. Break down food into its smallest components. 2. Absorb the nutrients. 3. To prevent microorganisms or other harmful compounds consumed with food from entering the tissues of the body.

1

The mechanical digestion of the small intestine moves chyme through the small intestine at a rate of _ centimeter a minute.

Fat

The presence of ___t in a food tends to enhance the flavor of foods because when the content of it increases, the intensity of the flavor also increases; this is because many *aromatic* compounds are soluble in fat, so the flavor of foods tends to last longer compared with flavor compounds dissolved in water.

Digestion

The simple definition of ________n is the breaking down of foods into absorbable components in the gastrointestinal (GI) tract.

Flavor

The smell of food often triggers the appetite. As you eat a food, its aroma will contribute to its _______r.

Flavor

The term ______r refers to the complete food experience of both the taste *and* aroma of food. Ex. When you eat a candy bar, you sense a sweet taste, but this term distinguishes it as specifically chocolate.

2

There are _ forms of digestion.

Villi

Thousands of fingerlike projections in the small intestine called _____i cover the walls to increase its surface area. They also mix the partially digested chyme with intestinal secretion.

True

True or false: A reason why you lose interest in eating when you have a cold or forms of nasal congestion is because foods loses some of its appeal when you can't smell it.

True

True or false: By the time the food enters the large intestine, it has been digested and the majority of nutrients have been absorbed.

True

True or false: Most taste buds are located on the tongue, but additional taste buds are found in the throat or elsewhere in the mouth.

False

True or false: Only chemical digestion, not mechanical digestion, occurs in the small intestine.

True

True or false: The cells lining your GI tract have a very brief life span. 3-5 days, then shed into the lumen/inside of the intestinal tract + replaced with new healthy cells.

False

True or false: The cells of the small intestine absorb water and electrolytes much more efficiently than the cells of the *large* intestine.

True

True or false: The process of chemical breakdown and absorption can be interrupted. Ex. The weight-loss drug orlistat, "Alli," claims to interfere with the chemical digestion of fat.

False

True or false: The sense of small is not important in the ability to taste foods.

True

True or false: The small intestine has tremendous surface area compared with the stomach, and its digestive secretions do most of the work when it comes to breaking down food into absorbable nutrients.

True

True or false: There are more microorganisms than human cells in your body, and many of them are located in your large intestine.

LES

Under normal conditions, when we swallow food, the _ _ _ relaxes and allows food to pass into the stomach. The stomach also relaxes to comfortably receive the food. After the food enters the stomach, this should close.

Aroma

We detect an ______a through the nose when we smell foods and, as we eat, food odors enter the mouth and migrate to the back of the throat and into the nasal cavities.

Stomach

When the bolus of food reaches the ________h, the lower part of the esophagus relaxes, allowing it to enter.

Epiglottis

When you "swallow down the wrong pipe," and then cough to expel the item, it is because the normal mechanism that protects your trachea/windpipe doesn't engage properly. This mechanism is the ________s, a flap of tissue that protects the trachea while swallowing. It make sure that food and drink go down the "correct pipe," the esophagus, instead of the trachea. If food gets lodged there, it can result in choking.

1, 1.5

You produce _ to _._ liters of saliva every day.

HCl

_ _ _ is a powerful acid made in the stomach that has digestive functions. It also helps to kill microorganisms and lower the pH in the stomach.

Segmentation

_____________n is a "sloshing" motion that thoroughly mixes the chyme with the chemical secretions of the intestine. Occurs in the small intestine.

Hydrochloric

____________c acid activates protein-digesting enzyme pepsin, enhances absorption of minerals, breakdown of connective tissue in meat, and the destruction of some ingested microorganisms. You'd think since it's such a strong chemical it would "digest" stomach too, but mucus produced there acts as a barrier between the acid and stomach lining, protecting it from irritation or damage.

Mechanical digestion

____________l __________n occurs through peristalsis, segmentation and pendular movement.

Mechanical

_________l digestion involves chewing, grinding, and breaking food apart in the mouth so that it can be comfortably swallowed.

Pendular movement

_________r __________t is a constrictive wave that involves both forward and reverse movements in the small intestine. It enhances nutrient absorption.

Peristalsis

_________s is the muscular activity and rhythmic contracts of digestion, that move food through the GI tract and mix it with enzymes. *Mechanical* digestion.

Chemical

________l digestion involves disgestive juices and enzymes breaking down food into absorbable nutrients that are small enough to enter the cells of the GI tract, blood, or lymph tissue. Breaking down foods with enzymes or digestive juices.

Electrolytes

________s are charged particles (positive or negative *ions*). Vomiting and diarrhea cause the loss of these in your body. Minerals that help maintain the body's fluid balance

Peristalsis

________s is the forward, rhythmic motion that moves food through the digestive system. It is a form of mechanical digestion because it influences motion, but does not add chemical secretions.

Saliva

_______a is watery fluid secreted by the salivary glands in the mouth. It moistens food and makes it easier to swallow. Released by glands in the mouth. Helps dissolve small food particles and allows us to comfortably swallow dry food. Made of water, electrolytes, some enzymes (like amylase for carbohydrates) and mucus.

Appetite

_______e is the psychological desire to eat or drink.

Umami

_______i is the name of one of the five categories of taste, specifically the savory one.

Gastrin

_______n is a digestive hormone produced in the stomach that stimulates digestive activities and increases motility and emptying. Stimulates the secretion of HCl.

Absorption

_______n is the process by which digested nutrients move into the tissues where they can be transported and used by the body's cells.

Heartburn

_______n is when hydrochloric acid from the stomach flows flows back into the esophagus and irritate its lining because the LES does not close after food enters the stomach. Causes a burning sensation in the middle of the chest.

Enzymes

_______s are substances that produce chemical changes or catalyze chemical reactions.

Mucus

_______s in saliva and other digestive juices is a viscous, slippery secretion. Helps lubricate the food, helps it stick together and protects the mouth.

Hunger

______r is the physical need for food.

Thirst

______t is the physical need for water.

Orlistat

______t, the component of Alli, works by preventing enzymes in the intestines from breaking down dietary fat. If the fat isn't broken down, your body can't absorb it, and it will pass through the GI tract and be eliminated in stool. Blocks absorption of about 25% of fat at a meal. Ex. Pepperoni pizza slice w/ 189 cals from fat for lunch, you'll only absorb 140 of them.

Alli

__i is the first Food and Drug Administration approved over-the-counter drug containing orlistat, which helps prevent some dietary fat from being absorbed into your body. FDA says it's for obese or overwight people who have other risk factors like diabetes, high cholesterol, and elevated blood pressure. Isn't a magic cure if you replace high-fat foods with nonfat, high-calorie foods. $50 a month.