Chapter one

Question 1

How many meters long is the GIT

Answer 1

9 M

Question 2

List GI functions

Answer 2

1. Digest the macronutrients protein, carbohydrates, and lipids from ingested food and beverage
2. Absorb fluids, digested macronutrients, micronutrients, and trace elements
3. Provide a physical and immunologic barrier to pathogens, foreign material, and potential antigens consumed with food or formed during passage of food through GIT
4. Coordinate a response to microbes and antigens with systematic immune system, resulting in controlled levels of tolerance or inflammation
5. Provide regulatory and biochemical signaling to the nervous system, often involving the intestinal microbiota, via the gut-brain axis.

Question 3

How much of food is digested and absorbed

Answer 3

90-97%

Question 4

Humans lack enzymes to digest

Answer 4

plants (fiber)

Question 5

fibrous foods and undigested carbohydrates are fermented to varying degrees by bacteria of colon; this process contributes ____ to ____% of the energy needed by humans

Answer 5

5% to 10%

Question 6

mucousa

Answer 6

lining of hollow tube in small intestine

Question 7

crypts

Answer 7

invaginations in mucosa

Question 8

crypt-villus units are lined with a single layer of ____ cells, many of which are _____ that contain____

Answer 8

epithelial cells; enterocytes; microvilli

Question 9

epithelial cells lining intestinal tract have a lifespan of how many days

Answer 9

3-5 days

Question 10

approximately ____% of energy requirement of the small intestine and ____% of the energy requirement of the cells lining the colon are supplied by nutrients

Answer 10

45% ; 70%

Question 11

After a few days of starvation, the intestinal mucosa atrophies - true or false

Answer 11

True; this justifies the clinical practice of feeding an individually orally or enterally

Question 12

starch is degraded by what enzyme in the mouth

Answer 12

salivary amylase

Question 13

In the stomach, the food is mixed with acidic fluid that contains ____ and ___ enzymes

Answer 13

proteolytic and lipolytic enzymes

Question 14

Chyme

Answer 14

when food passes through stomach and is in small intestine

Question 15

When food reaches the small intestine, it stimulates

Answer 15

the release of hormones that stimulates the production and release of powerful enzymes form the pancreas and bile from the gallbladder

Question 16

How much fluid is secreted into GI tract, and how much is ingested through dietary intake

Answer 16

7L of fluid secreted, 2L ingested

Question 17

How much fluid in the lumen is reabsorbed

Answer 17

100mL
(7L in small intestine, 2L in large intestine)

Question 18

Most nutrients absorbed from the GIT enter the ____ vein for transport to the ______

Answer 18

portal vein transported in the liver where they are stored, transformed into other substances, or released

Question 19

Dietary fats are transported into the bloodstream via the ____

Answer 19

lymphatic system

Question 20

fermentable dietary fiber and resistant starches are _____ located within the lumen of the intestinal segments

Answer 20

fermented by microbiota which produces short chain fatty acids and gas

Question 21

short chain fatty acids provide a fuel source for

Answer 21

cells of intestine which stimulate intestinal cell renewal and function, enhance immune function, and regulate gene expression

Question 22

True or false; some carbs have a prebiotic function

Answer 22

true

Question 23

enzymatic hydrolysis

Answer 23

digest food using chemical process

Question 24

digestive enzymes are synthesized in ____,____, and ____ and are released into the GIT ____

Answer 24

digestive enzymes synthesized in special cells of the mouth, stomach, and pancreas are released into the lumen

Question 25

Digestive enzymes synthesized in enterocytes in the small intestine remain ____

Answer 25

embedded within the brush border membrane

Question 26

except for fiber and resistant carbohydrates, digestion of food is completed essentially in

Answer 26

small intestine

Question 27

A-Amylase substrate and action and resulting product

Answer 27

starch; hydrolysis to form dextrins and maltose

Question 28

lingual lipase substrate and action and resulting product

Answer 28

triglyceride; hydrolysis to form diglyceride and free fatty acids

Question 29

pepsin substrate and action and resulting product

Answer 29

protein; hydrolysis of peptide bonds to form peptides and amino acids; secretion from gastric glands in stomach

Question 30

gastric lipase substrate and action and resulting product

Answer 30

triglyceride; hydrolysis to form diglyceride and free fatty acid

Question 31

lipase substrate and action and resulting product and final absorbed product

Answer 31

Secreted from pancreatic acinar cells; acting in duodenum
fat; hydrolysis to form monoglycerides and fatty acids; incorporated into micelles; fatty acids into mucosal cells, reesterfied as triglycerides

Question 32

Cholesterol esterase substrate and action and resulting product

Answer 32

exocrine secretions from pancreatic acinar cells; acting in duodenum;
Sterols; hydrolysis to form esters of cholesterol and fatty acids; incorporated into micelles

Question 33

A amylase substrate and action and resulting product

Answer 33

exocrine secretions from pancreatic acinar cells acting in duodenum; starch and dextrins; hydrolysis form dextrins and maltose

Question 34

Trypsin substrate and action and resulting product

Answer 34

protein and polypeptide; hydrolysis of interior peptide to form polypeptide (exocrine cells in duodenum)

Question 35

Chymotrypsin substrate and action and resulting product

Answer 35

exocrine cells of pancreas acting in duodenum
Protein and polypeptide; hydrolysis of inferior peptide bonds to form polypeptides