Chapter 4

The sense of taste is important because:

-foods that taste sweet usually contain carbs -chemicals that elicit bitter taste are often poisonous -sour taste can indicate the presence of ascorbic acid -sodium stimulates the taste buds to detect the salty taste -the umami taste is detected when certain amino acids stimulate taste buds

What are causes of diarrhea?

More water than normal is secreted into the GI tract and the GI tract absorbs less water than normal.

Symptoms of GERD

Nausea, gagging, hoarseness and vomiting

These contribute to heartburn:

-having excess body fat -overeating -smoking cigarettes

swollen veins in the anal canal are called

Hemorrhoids

The innermost layer, the mucosa, surrounds the lumen of the digestive tract, which is a hollow space through which food and fluids pass. (T or F)

True

Pancreas

an accessory organ of the digestive tract that produces and secretes many of the enzymes that break down carbohydrates, protein, and fat in the GI tract.

Anosmia

complete inability to detect odors

Gallbladder

concentrates and stores bile until it is needed for fat digestions and absorption.

accessory organs

liver, gallbladder, pancreas are accessory organs of the gastrointestinal system that play major roles in digestion, even though chyme does not move through them.

A slippery, alkaline substance that protects the stomach from its acid and digestive enzymes is called _______.

mucus

Acidic

pH less than 7

Components of saliva include

salivary amylase, lingual lipase

To reduce the likelihood that young children will choke on food, caregivers should:

-Not leave children unattended when they are eating -not allow children to run with food in their mouths -encourage children to take smaller bites and not hold extra food in their mouths -avoid giving foods to young children that are likely to cause choking (grapes, carrots, hot dogs, nuts, mini marshmallow, popcorn, pretzels, peanut butter, hard candy, chewing gum, hard candy, gum, large pieces of meat. -Cut foods into small pieces that can be easily chewed and swallowed

To remedy constipation you should

drink more water, intake more fiber

Alkaline (basic)

having a pH greater than 7

Prompt treatment for diarrhea is especially important for

infants and the elderly

Amylase is the enzyme needed to digest ______ .

starch

The stomach empties in about _______ hours depending on the contents and size of the meal.

3-4

Salivary amylase

Initiates chemical digestion in the mouth. the amylase begins the breakdown of starch

The pressure commonly found with chronic constipation can sometimes force small pouches to form in the wall of the colon called:

diverticulli

duodenum

first part of the small intestine that is about 10 inches long. Within the duodenum, the acidic stomach contents mix with alkaline fluids secreted by the pancreas and gallbaldder.

Almost all of the macronutrients are digested and obsorbed:

in the small intentestine

Crohn's disease often results in the formation of:

intestinal blockages intestinal abscesses fistulas

A person this dumping syndrome may often experience the following soon after eating a meal:

sweating, nausea, abdominal fullness

ileum

the last and longest portion of the small intestine is 5 to 9 feet long

The length of time it takes for the stomach to empty

varies with the amount of liquid consumed and is influenced by the amount of food and type of nutrients consumed

What is generally an unpleasant experience but helpful because it prevents toxic substances from entering the small intestine?

vomiting

Peristalsis

waves of muscular contractions that move food through the digestive tract

active transport

Some nutrients move from the lumen of the intestine and into an enterocyte against the concentration gradient; that is, the concentration of the nutrient is higher inside the absorptive cell than in the lumen. Absorption of these nutrients requires both a unique transport protein and energy. Enterocytes rely on active transport to absorb glucose and amino acids

Villi

Tiny finger-shaped structures that cover the inner surface of the small intestine and provide a large surface area through which digested food is absorbed

The enzymatic digestion of starch that began in the mouth stops in the stomach because salivary amylase does not function when the pH is lower than 4.5. (T or F)

True

Epiglottis

a flap of tough tissue that prevents the food from entering the larynx and trachea

Lumen

a hollow space through which food and fluids pass

Enzyme

a protein that speeds up the rate of a chemical reaction without being altered in the process

HC1

a strong acid that contributes to the low pH of gastric juice

Saliva

a watery fluid that contains mucus and a few enzymes, including lysozyme, salivary amylase, and lingual lipase.

Lysozyme

can destroy some bacteria that are in food or the mouth

symptoms of a peptic ulcer include

deep, dull upper abdominal pain feeling of fullness 2 hours after eating

3 sections of the small intestine

duodenum, jejunum, ileum

enterocytes

each villus has an outer layer of absorptive cells that are also called enterocytes

In a living person, the GI tract:

is a hollow, muscular tube that extends approximately over 16 feet in length

Mastication

is a physical activity that prepares solid foods for swallowing and chemical digestion. Such mechanical activity makes it easier to swallow and increases its surface area, which enables enzymes to have greater access to nutrients

(GER) gastroesophageal reflux (heartburn or acid reflux)

is pain typically felt in the upper chest that results from the passage of acidic contents from the stomach into the esophagus.

constipation can be caused by a diet that is ______ in fiber and water

low

The main function of the lower portion of the stomach:

mixing food with gastric juice to form chyme (kime), a semiliquid mass

simple diffusion

occurs when the concentration of a particular nutrient is higher in the lumen of the small intestine than in an enterocyte. This form of transport does not require the input of energy. The digestive tract absorbs many water-soluble vitamins, lipids, and some minerals by simple diffusion.

accessory organs that assist the functioning of the GI tract

teeth, tongue, salivary glands, liver, gallbladder, pancreas

Two major components of the digestive system

the GI tract and accessory organs

If the digestive system is not functioning properly:

the entire body eventually shows signs and symptoms of disease

which of the following are functions of the stomach?

Produces and secretes HCI, begins chemical digestion of protein, secretes chemical messages that regulates digestion

How is the stomach lining protected from the strongly acidic pH of its contents?

a mucus lining

The small intestine and the _______ produce most of the digestive enzymes

pancreas

Bioavailability

refers to the extent to which the digestive tract absorbs a nutrient and how well the body uses it

jejunum

second part of the small intestine that is 3-5.5 feet long. Most digestion and nutrient absorption occurs in the upper part of the small intestine, primarily in the duodenum and upper jejunum.

esophagus

a muscular tube that extends about 10 inches from the pharynx to the upper portion of the stomach

facilitated diffusion

Although the nutrient moves down its concentration gradient, it still needs to be carried by a special transport protein within the membrane of the enterocyte. Transport proteins are specific for the type of nutrient they are responsible for carrying. Absorption of the simple sugar fructose occurs by facilitated diffusion

Bile

a greenish-yellow, bitter-tasting fluid that contains cholesterol, minerals, bile salts, and bilirubin. Bilirubin is a waste product that results from the breakdown of hemoglobin, the iron-containing pigment in red blood cells. (the liver makes about 2 to 4 cups of bile daily. bile flows from the liver into the gallbladder via ducts.