Lower GIT

Question 1

what is the function of the small intestine

Answer 1

absorption of nutrients and mixing of chyme with secretions from the liver and pancreas such as bile or bicarbonate for neutralisation of stomach acid

Question 2

what are the two mechanisms of the small intestine and how do they work

Answer 2

spontaneous contractions of the smooth muscle that increase post prandially, contractions are greater in the duodenum

migrating motor complex regulating contraction of smooth muscle distally from the duodenum

Question 3

what is segmentation in the small intestine

Answer 3

mixing of chyme with secretions via rhythmic divisions and subdivisions within the si

Question 4

how does propulsion occur in the small intestine

Answer 4

sequential contraction of adjacent circular smooth muscle following by proximal relaxation

Question 5

how long is one propulsion

Answer 5

about 10cm

Question 6

what is a full length contraction of the small intestine called

Answer 6

peristaltic brushes

Question 7

what three plexi control mediate motility

Answer 7

myenteric, submyenteric, intrinsic

Question 8

what do the plexi in the SI do

Answer 8

enables segmentation and short peristaltic waves to occur

Question 9

what peptides can modulate motility and rhythm of peristaltic waves in he si

Answer 9

VIP, substance p and opioids

Question 10

what effect does enteric glycogen have on motility

Answer 10

inhibits it so that there can be more absorption

Question 11

describe the gastrio illio reflex

Answer 11

distension of the stomach causes relaxation of the ileum (feedforward) but over distension of the ileum causes the stomach to reduce gastric emptying into the duodenum (feedback)

Question 12

what is parioltyic ilues

Answer 12

ability for external organs outside the GIT to modulate motility

Question 13

what are the 4 types of laxatives for constipation

Answer 13

secretary - increases intestinal secretions to act as lube
osmotic such as epsom salts which encourage osmosis of water from ecf to lumen
emollients such as parafen - lubricating
bulk forming agents such as bran high in fibre

Question 14

what is the connection between the small intestine called

Answer 14

ileo-caecal sphincter

Question 15

what is the outer layer of the large intestine called

Answer 15

tanie coli

Question 16

describe the muscles of the large intestine e

Answer 16

mainly circular muscle that gets thicker towards the end of the colon towards the rectum

Question 17

what is the large intestine divided into

Answer 17

haustra which controlled contractions of the circular muscle

Question 18

how does propulsion occur in the large intestine

Answer 18

sequential contractions of haustra in peristaltic waves

Question 19

what is the speed of movement of chyme in the colon before and after food

Answer 19

before food it is about 5cm per hour

after eating it is about 10 cm per hour

Question 20

which part of the colon contacts

Answer 20

ascending an transverse contract but descending and sigmoid causes distention

Question 21

what is the defication reflex

Answer 21

distention of the rectum causing relaxation of the anal sphincter

Question 22

what are the three types of contraction in the large intestine

Answer 22

mass movements - prolonged peristaltic
anti peristaltic contractions to allow more water and electrolytes to be absorbed halting motility
segmentation contractions shopping and mixing which cause formation of the haustra

Question 23

what are the symptoms of IBS

Answer 23

nausea 
stomach cramps 
diarrhoea 
constipation 
frequent defication

Question 24

how can you relieve symptoms of IBS

Answer 24

bulk forming laxatives
antispasmodic - reduce cramping - peppermint oil and increase motility
anti motility - lowpermide - reduce frequent defections
TCA’s and SSRI to reduce cramps