lec 9

Question 1

The small intestine functions

Answer 1

the digestion and absorption of nutrients

Question 2

The small intestine

Answer 2

1. mixes nutrients with digestive enzymes,
2. exposes the digested nutrients to the absorptive mucosa,
3. propels any non-absorbed material to the large intestine

Question 3

Segmentation contractions

Answer 3

A section of small intestine contracts, sending the intestinal contents (chyme) in both orad and caudad directions.

Question 4

Segmentation contractions

Answer 4

section of small intestine contract then relaxes and the contents move back into the segment

Question 5

segmentation contractions produces

Answer 5

back-and-forth movement

Question 6

This back-and-forth movement produced by segmentation contractions causes

Answer 6

mixes nutrients with digestive enzymes, without any net forward movement of the chyme.
exposes the digested nutrients to the absorptive mucosa

Question 7

The maximum frequency of the segmentation contractions in the small intestine is determined by the frequency o

Answer 7

electrical slow waves in the intestinal wall

Question 8

maximum frequency of the segmentation contractions =

Answer 8

12 per minute in the duodenum and proximal jejunum)

Question 9

maximum frequency occurs

Answer 9

only under extreme conditions of stimulation

Question 10

the maximum frequency of terminal ileum

Answer 10

8-9 contractions per minute

Question 11

atropine effect on The segmentation contractions

Answer 11

The segmentation contractions become exceedingly weak when the excitatory activity of the enteric nervous system is blocked by the drug atropine

Question 12

Peristaltic contractions function

Answer 12

1.cause progression of chyme toward the ileocecal valve, Cause propel the chyme through the small intestine toward the large intestine
to spread out the chyme along the intestinal mucosa

Question 13

peristalsis occurs

Answer 13

after digestion and absorption have taken place.

Question 14

peristaltic waves are

Answer 14

highly coordinated Contraction behind the bolus and, simultaneously, relaxation in front of the bolus cause the chyme to be propelled caudally

Question 15

The peristaltic reflex is

Answer 15

coordinated by the enteric nervous system

Question 16

The peristaltic waves can occur velocity

Answer 16

of 0.5 to 2.0 cm/sec (averages only 1 cm/min)

Question 17

The peristaltic waves faster in

Answer 17

the proximal intestine

Question 18

The peristaltic waves slower in

Answer 18

the terminal intestine

Question 19

The peristaltic waves are normally weak and usually die out after traveling only

Answer 19

3 to 5 centimeters, rarely travel farther than 10 centimeters

Question 20

The peristaltic waves forward movement of the chyme is very slow so it takes

Answer 20

3 to 5 hours for passage of chyme from the pylorus to the ileocecal valve

Question 21

Activity of the small intestine is greatly increased

Answer 21

1. after a meal
2. gastro-enteric reflex
3. several hormonal factors

Question 22

Activity of the small intestine is greatly increased after a meal is caused by

Answer 22

the beginning entry of chyme into the

duodenum, causing stretch of the duodenal wall.

Question 23

gastro-enteric reflex is initiated by

Answer 23

distention of the stomach and conducted principally through the myenteric plexus from the stomach down along the wall of the small intestine

Question 24

enhance intestinal motility by

Answer 24

gastrin, CCK, insulin, motilin, and serotonin

Question 25

inhibit small intestinal motility by

Answer 25

secretin and glucagon

Question 26

peristalsis, is predominates in

Answer 26

the esophagus, and the large intestine

Question 27

segmentation contractions is predominates in

Answer 27

the large intestine and small intestine

Question 28

Peristaltic rush

Answer 28

powerful and rapid peristalsis due to infectious diarrhea

Question 29

peristalsis in the small intestine

Answer 29

normally weak,

Question 30

Peristaltic rush is initiated

Answer 30

1. by nervous reflexes that involve the autonomic nervous system and brain stem
2. myenteric plexus reflexes

Question 31

Weak anti-peristalsis is sometime seen

Answer 31

in the colon

Question 32

Gut law

Answer 32

waves pass regularly in an oral-caudal

direction

Question 33

The powerful peristaltic contractions (rash)

Answer 33

1.travel long distances in the small intestine within minutes
2.sweepingتكنس the contents of the intestine into the colon and

thereby relieving the small intestine of 1.irritative chyme and 2.excessive distention

Question 34

Movements caused by the muscularis mucosae and muscle fibers of the Villi

Answer 34

1.cause short folds to appear in the intestinal mucosa> ↑ the surface area→ ↑ absorption
2.individual fibers from this muscle extend into the intestinal villi and cause them to
contract intermittently

Question 35

ggg

Answer 35

41+40