24.9 Small intestine

Question 1

what is the site of greatest amt of digestion and absorption?

Answer 1

small intestine

Question 2

what gets absorbed in the small intestine?

Answer 2

nutrients and H_2O

Question 3

what are the 3 divisions of the small intestine?

Answer 3

duodenum
jejunum
ileum

Question 4

how long is the duodenum?

Answer 4

25 cm beyond the pyloric sphincter

Question 5

how long is the jejunum?

Answer 5

2.5 m

Question 6

how long is the ileum?

Answer 6

3.5 m

Question 7

by how much do the modifications to the surface area increase the surface area of the small intestine?

Answer 7

600 x

Question 8

what are the surface area modifications to the small intestine?

Answer 8

plicae circularis
villi
microvilli

Question 9

what is the common name for plicae circularis?

Answer 9

circular folds

Question 10

what are the villi of the sm intestine?

Answer 10

folds of the mucosa

Question 11

what do the villi contain?

Answer 11

capillaries and lacteals

Question 12

what are lacteals?

Answer 12

dead end lymph vessels that absorb water fluid from intestines to the great lymph vessels

Question 13

what are microvilli of the sm intestine?

Answer 13

folds of cell membrane of absorptive cells on the villi

Question 14

what are the cells of the duodenum?

Answer 14

absorptive cells
goblet cells
endocrine cells
granular cells

Question 15

what is the fn of the absorptive cells of the duodenum?

Answer 15

produce digestive enzymes and absorb digested food

Question 16

what specialized membrane do the absorptive cells of the duodenum have?

Answer 16

microvilli

Question 17

what is the fn of goblet cells in the duodenum?

Answer 17

produce protective mucus

Question 18

what is the fn of endocrine cells of the duodenum?

Answer 18

produce regulatory hormones

Question 19

what cells of the duodenum produce digestive enzymes and absorb digested food?

Answer 19

absorptive cells

Question 20

what is the fn of the granular cells of the duodenum?

Answer 20

may help protect from bacteria

Question 21

what are the two types of glands in the duodenum?

Answer 21

intestinal glands

duodenal glands

Question 22

what are the intestinal glands and where are they located?

Answer 22

tubular glands in mucosa at the base of villi

Question 23

what are the duodenal glands and where are they located?

Answer 23

tubular mucus glands of the submucosa, open into the base of the intestinal gland

Question 24

what are the changes in the sm intestine further away from the stomach?

Answer 24

gradual decrease in diameter
gradual decrease in thickness of intestinal wall
decrease in # of circular folds
decrease in # of villi
increase in goblet cells

Question 25

the major site of nutrient absorption in the sm intestines is in the

Answer 25

jejunum and ileum

Question 26

what are Peyer's patches?

Answer 26

lymphatic nodules

Question 27

where are Peyer's patches located?

Answer 27

mucosa | submucosa

Question 28

what is the ileocecal jnct?

Answer 28

where ileum meets lg intestine

Question 29

what sphincters are located at the ileocecal jct?

Answer 29

ileocecal sphincter | ileocecal valve

Question 30

what stimulates the duodenal glands?

Answer 30

vagus nerve stimulation secretin chemical or tactile irritation of duodenal mucosa

Question 31

what 4 things are secreted by the small intestines?

Answer 31

``` mucus digestive enzymes: disacharidases peptidases nucleses ```

Question 32

what is the fn of the mucus of the sm intestines?

Answer 32

protects against digestive enzymes and stomach acids | lubricant

Question 33

where are the digestive enzymes of the sm intestine located?

Answer 33

bound to the membranes of the absorptive cells

Question 34

what type of digestive enzyme breaks down disacharides to monosaccharides (ex maltose to glucose)?

Answer 34

disaccharidases

Question 35

what do disaccharidases do?

Answer 35

break down disaccharides to monosaccharides

Question 36

what do peptidases do?

Answer 36

hydrolyze peptide bonds in proteins

Question 37

what do nucleases do?

Answer 37

bread down nucleic acids

Question 38

what type of digestive enzyme breads down nucleic acids?

Answer 38

nucleases

Question 39

what type of digestive enzyme hydrolyzes peptide bonds in proteins?

Answer 39

peptidase