Lecture 27 Unit 4

Question 1

how long is the small intestine

Answer 1

3 m in total length (10 feet)

Question 2

what is the diameter of the small intestine

Answer 2

2.5 cm (1 inch)

Question 3

what happens in the small intestin

Answer 3

most digestion and absorption

Question 4

what are the 3 sections of the small intestine

Answer 4

-duodenum, jejunum, and ileum

Question 5

how long is the dudoenum

Answer 5

25 cm/ 10 inches

Question 6

how long is the jejunum

Answer 6

1 m/ 3 feet

Question 7

how long is the ileum

Answer 7

2 m/ 6 feet

Question 8

why does the total length of the small intestine increase to 6.5 m in cadavers

Answer 8

loos of smooth muscle tone

Question 9

what do villi and microvilli do

Answer 9

increase surface area for absorption

Question 10

what do brush border enzymes do

Answer 10

participate in chemical breakdown of carbohydrates, proteins, and nucleosides

Question 11

where is pancreatic juice found and what does it contain

Answer 11

found in the lumen with chime and contains amylase, proteases, lipase, and nucleases

Question 12

how much pancreatic juice is produced per day

Answer 12

~2 liters

Question 13

what is the ph of pancreatic juice

Answer 13

7.1-8.2

Question 14

what is in pancreatic juice

Answer 14

water, salts, sodium bicarbonate, enzymes

Question 15

what are the ezymes secreted by the pancreas

Answer 15

• pancreatic amylase
• trypsin
• chymotrypsin
• carboxypeptidase
• elastase
• pancreatic lipase
• ribonuclease
• deoxyribonuclease

Question 16

what are the proteases secreted by the pancreas

Answer 16

• trypsin
• chymotrypsin
• carboxypeptidase
• elastase

Question 17

what are the nucleases secreted by the pancreas

Answer 17

• ribonuclease

- deoxyribonuclease

Question 18

what does enteropeptidase do

Answer 18

activates trypsinogen to trypsin

Question 19

what does trypsin activate

Answer 19

chymotrypsin, procarboxypeptidase, and proelasease

Question 20

what digests carbohydrates in the mouth, stomach, pancreas, and small instestine

Answer 20

mouth-salivary amylase
stomach-only mechanical digestion
pancreas- pancreatic amylase in pancreatic juide
small intestine-maltase, sucrase, lactase

Question 21

what is lactose intolerance

Answer 21

those without lactase will have bacteria ferment lactose and the result will be gas and diarrhea

Question 22

what are the steps in absorption of monosaccharides

Answer 22

1. absorption into epithelial cells

2. movement out of epithelial cell into bloodstream

Question 23

what is absorbed from monosaccharides into epithelial cells

Answer 23

glucose and galactose by sodium symporter and fructose by facilitated diffusion

Question 24

how do monosaccharides move out of epithelial cells into bloodstream

Answer 24

facilitated diffusion

Question 25

what digests proteins in the mouth, stomach, pancreas, and small intestine

Answer 25

mouth- mechanical digestion only stomach- HCl denatures proteins and pepsin breaks proteins into smaller polypeptides pancreas-pancreatic enzymes in pancreatic juice continue to split peptide bonds between amino acids small intestine- amino peptidase and dipeptidase

Question 26

what does aminopeptidase do in the digestion of proteins

Answer 26

splits off amino acids at the amino end of polypeptides

Question 27

what does the dipeptidase do in digestion of proteins

Answer 27

split apart two amino acid chains

Question 28

what are the steps in absorbing amino acids and dipeptides

Answer 28

1. absorption into epithelial cells of duodenum and jejunum | 2. movement out of epithelial cell into blood

Question 29

how are amino acids and dipeptides absorbed into epithelial cells of small intestine

Answer 29

active transport with Na+ or H+ ions (symporters using secondary active transport)

Question 30

how do amino acids and dipeptides move out of epithelial cells

Answer 30

facilitated diffusion

Question 31

where do digestion of lipids begin

Answer 31

the mouth

Question 32

what digests lipids in the mouth, stomach, pancreas, liver, and small intestine

Answer 32

``` mouth-lingual lipase -stomach-gastric lipase pancreas-pancreatic lipase in pancreatic juice continues to split triglycerides into fatty acids and monoglycerides liver- bile small intestine-none ```

Question 33

what are the steps in the absorption of lipids

Answer 33

1. short chain fatty acids are absorbed by simple diffusion 2. long chain fatty acids and monoglycerdies are sequestered within tiny micelles after emulsification by bile, also enter cells by simple diffusion, leaving bile salts behind 3. inside epithelial cells fats are rebuilt and coated with protein to form chylomicrons 4. chylomicrons leave intestinal cells by exocytosis into interstitial fluid where they can only enter lacteals

Question 34

what are bile salts reabsorbed and recycled by

Answer 34

the liver

Question 35

how are certain fat soluble vitamins able to enter cells

Answer 35

vitamins A, K, D3, and E cane enter with lipids

Question 36

how to chylomicrons travel and how are they removed?

Answer 36

travel in lymphatic system to reach subclavian veins and are removed from blood by liver and fat tissue

Question 37

what is the bodys source of electrolytes

Answer 37

GI secretions, ingested foods and liquids

Question 38

how do electrolytes enter epithelial cells

Answer 38

by diffusion and secondary active transport

Question 39

what ions use active transport to move

Answer 39

sodium, potassium ,iron, magneium, and phosphate

Question 40

how do chloride iodide and nitrate ions move

Answer 40

passive tranport

Question 41

what does intestine Ca2+ absorption require

Answer 41

vitamin D and parathyroid hormone

Question 42

what are the fat soluble vitamins

Answer 42

A, K, D3 and E

Question 43

how do fat soluble vitamins travel and what are they absorbed by

Answer 43

travel in micelles and are absorbed by simple diffusion with lipids

Question 44

how are water soluble vitamins absorbed

Answer 44

by diffusion

Question 45

what must vitamin B12 do before being transported into cells of ileum

Answer 45

combine with intrinsic factor from the stomach parietal cells

Question 46

what is vitamin B12 absorbed by

Answer 46

receptor mediated endocytosis

Question 47

how much fluid enters GI tract per day

Answer 47

9 L

Question 48

how much water does small intestine absorb a day

Answer 48

8 L

Question 49

how much water does large intestine absorb of the last liter

Answer 49

90%

Question 50

how is water absorption accomplished

Answer 50

by osmosis through cell membranes into cells and then from the cells into the capillaries inside the intestinal villi

Question 51

how much is excreted through feces

Answer 51

0.1 L