Lesson 9.5 Absorption and Malabsorption 213

E XERCISES A. Review the Case Report on this spread before answering the questions.

LO 9.8, 9.9, and 9.10 Understand

1. What is the meaning of the term spasmodic episodes?

2. What kind of specialist referred Mrs. Stark to the nutritionist?

3. When Mrs. Stark’s condition flares up, what symptoms are present?

4. What procedure did Dr. Grabowski perform to get a definitive diagnosis for Mrs. Stark?

5. Why did Mrs. Stark not get any relief from her previous doctor’s recommendations for a

low-fat, high-carbohydrate diet?

B. Construct the correct medical term to match the definitions. Review the WAD before you fill in the blanks. LO 9.1, 9.6, 9.9, and 9.10 Apply

1. inadequate gastrointestinal absorption of nutrients / /

P R/CF S

2. abnormally frequent and loose stools / /

P R/CF S

3. examination of a hollow structure with a special instrument / /

P R/CF S

4. excessive amount of gas in stomach and intestines / /

P R/CF S

5. the instrument used for endoscopy / /

P R/CF S

S  5  Suffix P  5  Prefix R  5  Root R/CF  5  Combining Form

WORD PRONUNCIATION ELEMENTS DEFINITION

celiac disease SEE-lee-ack diz-EEZ S/ R/ P/ R/

-ac pertaining to celi- abdomen dis- apart -ease normal function

Disease caused by sensitivity to gluten

diarrhea die-ah-REE-ah P/ R/

dia- complete -rrhea flow, discharge

Abnormally frequent and loose stools

endoscopy

endoscope

en-DOS-koh-pee

EN-doh-skope

P/ S/ S/

endo- inside, within -scopy to examine, view -scope instrument for viewing

The use of an endoscope

Instrument used to examine the interior of a tubular or hollow organ

flatulence

flatus

FLAT-you-lents

FLAY-tus

S/ R/

-ence forming flatul- excessive gas, flatus Latin blowing

Excessive amount of gas in the stomach and intestines Gas or air expelled through the anus

glycogen GLYE-koh-jen S/ R/CF

-gen to produce glyc/o- sugar/glucose

The body’s principal carbohydrate reserve, stored in the liver and skeletal muscle

malabsorption mal-ab-SORP-shun S/ P/ R/

-ion action, condition mal- bad, difficult -absorpt- swallow, take in

Inadequate gastrointestinal absorption of nutrients

portal vein POR-tal VANE portal, Latin gate vein, Latin vein

The vein that carries blood from the intestines to the liver

starch STARCH Anglo-Saxon stiffen Complex carbohydrate made of multiple units of glucose attached together

villus villi (pl)

VILL-us VILL-eye

Latin shaggy hair

Thin, hairlike projection, particularly of a mucous membrane lining a cavity

Word Analysis and Definition

Study Hint

Endoscope is a generic (general) term

that means any instrument (scope) used to examine

the inside (endo) of a tubular or hollow organ. The

instrument obtains its specific name from the organ

it is used to examine. Thus, an instrument used to

view a stomach is a gastroscope specifically, but it is

also an endoscope in general.

alL13792_ch09_191-222.indd 213alL13792_ch09_191-222.indd 213 3/20/15 9:45 AM3/20/15 9:45 AM

Final PDF to printer

214 Chapter 9 The Digestive System

Chemical Digestion, Absorption, and Transport (continued)

Proteins (LO 9.8) Proteins are only 10 to 20% digested when they

arrive in the duodenum and small intestine. Enzymes

produced by cells in the small intestine, and the

pancreatic enzyme trypsin, break down the remaining

proteins into amino acids. The amino acids are carried away in the blood and

are transported to cells all over the body to be used as

building blocks for new tissue formation.

Lipids (LO 9.8) Lipids (fats) enter the duodenum and small intestine

as large globules. These have to be emulsified by

the bile salts into smaller droplets so that pancreatic

lipase (fat-reducing enzymes) can digest them

into very small droplets of free fatty acids and

monoglycerides. These small droplets are taken up by the lacteals

(lymphatic vessels) inside the villi and then move into

the lymphatic system. The droplets now comprise

a milky, fatty lymphatic fluid called chyle, which

eventually reaches the thoracic duct and moves into

the bloodstream (see Chapter 7). Chyle is stored in

adipose tissue. The fat-soluble vitamins A, D, E, and K

are absorbed with the lipids.

Water (LO 9.8) Water has no caloric value and makes up approximately

60% of your body weight (about 10 gallons). Your small

intestine absorbs 92% of your body’s water, which is

taken into the bloodstream through the capillaries in the

villi. Water-soluble vitamins, C and the B complex, are

absorbed with water except for B 12 .

You can survive 6 to 8 weeks without food, but only

a few days without water.

Minerals (LO 9.8) Minerals are absorbed along the whole length of

the small intestine. Iron and calcium are absorbed

according to the body’s needs. The other minerals are

absorbed regardless of need, and the kidneys excrete

the surplus.

The major minerals are sodium (Na), potassium

(K), calcium (Ca), and magnesium (Mg).

Disorders of Malabsorption (LO 9.8) The term malabsorption syndromes refers to a group

of diseases in which intestinal absorption of nutrients

is impaired.

Malnutrition can arise from malabsorption, but

can also result from a lack of food, as with famine and

poverty. Malnutrition can also result from a loss of

appetite in people with cancer or a terminal illness.

Lactose intolerance occurs when the small

intestine is not producing enough of the enzyme

lactase to break down the milk sugar lactose. The

result is diarrhea and cramps. Lactase can be taken

in pill form before eating dairy products, and milk

products can be avoided.

Crohn disease (or regional enteritis ) is an

inflammation of the small intestine, frequently in the

ileum and occasionally also in the large intestine. The

symptoms are abdominal pain, diarrhea, fatigue, and

weight loss. There is no cure.

Celiac disease is an autoimmune disease that

damages the villi of the small intestine and i nterferes

with the absorption of nutrients. It is due to an

intolerance to a protein, gluten, found in wheat,

barley, and rye products. It affects about 1% of the

population in the United States. In addition, there is a

nonceliac sensitivity (allergy) to gluten products that

affects about 4% of the population.

Constipation occurs when fecal movement through

the large intestine is slow and thus too much water is

reabsorbed by the large intestine. The feces become

hardened. Constipation can be caused by lack of

dietary fiber, lack of exercise, and emotional upset.

Gastroenteritis (stomach “flu”) is an infection of

the stomach and intestine that can be caused by a large

number of bacteria and viruses. It causes vomiting,

diarrhea, and fever. An outbreak of gastroenteritis can

sometimes be traced to contaminated food or water.

Dysentery is a severe form of bacterial gastro-

enteritis with blood and mucus in frequent, watery

stools.

Malnutrition, malabsorption, and severe forms of

diarrhea and vomiting can cause dehydration and an

electrolyte imbalance, possibly leading to coma and

death.

Lesson 9.5(cont’d)

Keynotes

• Proteins are broken down into

amino acids.

• Minerals are electrolytes.

• In malnutrition, the body breaks

down its own tissues to meet its

nutritional and metabolic needs.

• Milk sugar is lactose. The enzyme

lactase breaks down lactose into

glucose.

• Diarrhea is caused by irritation

of the intestinal lining that

causes feces to pass through

the intestine too quickly for

adequate amounts of water to be

reabsorbed.

Abbreviations

Ca calciumED emergency department K potassium Mg magnesium Na sodium

alL13792_ch09_191-222.indd 214alL13792_ch09_191-222.indd 214 3/20/15 9:45 AM3/20/15 9:45 AM

Final PDF to printer

Lesson 9.5 Absorption and Malabsorption 215

E XERCISES A. Seek and find the correct medical terms to fill in the blanks. The answers to the following questions can all be found on the two-page spread open in

front of you. LO 9.8 and 9.11 Understand

1. What proteins break down into:

2. Another name for minerals:

3. Milky fluid that results from the digestion and absorption of fats:

4. Term used to describe all types of fatty compounds:

5. Break up into small droplets to suspend in a liquid:

B. Continue searching for the correct answer. LO 9.8 and 9.11 Understand

1. Lymphatic vessel that carries chyle away from the intestine:

2. Inorganic compounds found in the earth’s crust:

3. Number of calories in an ounce of water:

4. Percentage of the body’s weight that is water:

5. List the four major minerals:

S  5  Suffix P  5  Prefix R  5  Root R/CF  5  Combining Form

WORD PRONUNCIATION ELEMENTS DEFINITION amino acid ah-ME-no ASS-id R/CF amin/o- nitrogen containing

acid, Latin sour The basic building block for protein

chyle KYLE Greek juice A milky fluid that results from the digestion and absorption of fats in the small intestine

Crohn disease KRONE diz-EEZ Burrill Crohn, New York gastroenterologist 1884–1983

Narrowing and thickening of terminal small intestine

dysentery DISS-en-tare-ee P/ R/

dys- bad, difficult -entery condition of the small intestine

Disease with diarrhea, bowel spasms, fever and dehydration

emulsify

emulsion (noun)

ee-MUL-sih-fye

ee-MUL-shun

S/ R/ S/

-ify to become emuls- suspend in a liquid -ion condition, action

Break up into very small droplets to suspend in a solution (emulsion) The system that contains small droplets suspended in a liquid

gastroenteritis GAS-troh-en-ter -EYE -tis S/ R/

R/CF

-itis inflammation -enter- intestine gastr/o stomach

Inflammation of the stomach and small intestine

lacteal LAK-tee-al S/ R/CF

-eal pertaining to lact- milk

A lymphatic vessel carrying chyle away from the intestine

lactose lactase

LAK-toes LAK-tase S/

R/

Latin milk sugar -ase enzyme lact- milk

The disaccharide in cows milk Enzyme that breaks down lactose to glucose

lipase LIE-paze S/ R/

-ase enzyme lip- fat

Enzyme that breaks down fat

lipid LIP-id Greek fat General term for all types of fatty compounds; e.g., cholesterol, triglycerides, and fatty acids

mineral MIN-er-al S/ R/

-al pertaining to miner- mines

Inorganic compound usually found in the earth’s crust

Word Analysis and Definition

alL13792_ch09_191-222.indd 215alL13792_ch09_191-222.indd 215 3/20/15 9:45 AM3/20/15 9:45 AM

Final PDF to printer

216 Chapter 9 The Digestive System

Splenic flexure

Descendingcolon(left)

Descendingcolon

Sigmoidcolon

Sigmoidcolon

Internal analsphincter

External anal sphincter

Rectum

Anal canal

Ascendingcolon(right)

Ileocecalvalve

Ileum

Cecum

Cecum

Vermiformappendix

Appendix

Hepatic flexure

Transverse colon

(b)

(a)

Lesson 9.6

Structure and Functions of the Large Intestine (LO 9.9) Structure of the Large Intestine (LO 9.9) Your large intestine is so named because its diam-

eter is much greater than that of your small intestine.

In your abdominal cavity, the large intestine forms

a perimeter around the central mass of the small

intestine.

At the junction between the small and large intes-

tines, a ring of smooth muscle called the ileocecal sphincter forms a one-way valve. This allows chyme

to pass into the large intestine and prevents the large

intestine’s contents from backing into the ileum.

The cecum is located at the beginning of the

large intestine. It is a pouch in the abdomen’s right

lower quadrant. A narrow tube with a closed end

(the vermiform appendix ) projects downward from

the cecum ( Figure 9.24a and b ). The function of the

appendix is not known.

The ascending colon begins

at the cecum and extends

upward to underneath the

liver. Here, it makes a sharp

turn at the hepatic flexure and

becomes the transverse colon.

At the left side of the abdo-

men, near the spleen at the

splenic flexure, the transverse

colon turns downward to form

the descending colon. At the

pelvic brim, the descending

colon forms an S-shaped curve

called the sigmoid colon.

This descends in the pelvis to

become the rectum and then the

anal canal.

The rectum has three transverse folds—rectal valves

that enable it to retain feces while passing gas (flatus).

The anal canal ( Figure 9.25 ) is the last 1 to 2 inches

of the large intestine, opening to the outside as the

anus. An internal anal sphincter, composed of smooth

muscle from the intestinal wall, and an external anal

sphincter, composed of skeletal muscle that can be

controlled voluntarily, guard the exit of the anus.

Functions of the Large Intestine (LO 9.9) Your large intestine has the following key functions:

• Absorption of water and electrolytes. The large

intestine receives more than 1 liter (1,000 ml)

of chyme each day from the small intestine. It

reabsorbs water and electrolytes to reduce the

volume of chyme to 100 to 150 ml of feces, which

are eliminated by defecation;

• Secretion of mucus that protects the intestinal wall

and holds particles of fecal matter together;

• Digestion (by the bacteria that inhabit the large

intestine) of any food remnants that have escaped

the small intestine’s digestive enzymes;

• Peristalsis happens a few times a day in the large

intestine to produce mass movements toward the

rectum; and

• Elimination of materials that were not digested or

absorbed.

Objectives

Once your small intestine has digested and absorbed the nutrients, the residual materials must be prepared in your large intestine so they can be eliminated from your body. The information in this lesson will enable you to use correct medical terminology to:

9.6.1 Describe the structure and functions of the large intestine.

9.6.2 Outline disorders of the large intestine.

The Large Intestine and Elimination

Keynotes

• A sphincter is a ring of smooth

muscle that forms a one-way

valve.

• Colon: Ascending to transverse to

descending to sigmoid to rectum

to anus.

FIGURE 9.24 Large Intestine. (a) Surface anatomy.

(b) X-ray of large intestine following barium enema.

▲

FIGURE 9.25 Anal Canal.

Rectal valveRectum

Hemorrhoidal veins

Anal canal

External anal sphincter

Internal anal sphincter

Anal columns Anus

▲

alL13792_ch09_191-222.indd 216alL13792_ch09_191-222.indd 216 3/20/15 9:45 AM3/20/15 9:45 AM

Final PDF to printer