large intestine

Question 1

what are the components of the small intestine?

Answer 1

caecum
-appendix
colon
-ascending
-transverse
-descending
-sigmoid
rectum

Question 2

what are the sharp corners called?

Answer 2

splenic flexure

hepatic flexure

Question 3

what are taenia coli?

Answer 3

focal areas of longitudinal muscle
3 bands for contraction
moving faecal material

Question 4

what are haustrae?

Answer 4

dips/indentations between pouches

Question 5

what are appendices epiploicae?

Answer 5

fatty tags

Question 6

what are the 2 anal sphincters?

Answer 6

internal
-involuntary
-SM
external
-voluntary
-skeletal muscle
together they maintain faecal continance

Question 7

what is the ileo-caecal junction?

Answer 7

junction between caecum and ascending colon
ileo-caecal valce
fold of mucosa, allows chime to pass from SI to LI
vermiform appendix leads off from caecum

Question 8

what are the similarities between ST & LI?

Answer 8

epithelium: simple columnar, with goblet cells
intestinal crypts
mucosal glands

Question 9

what are the differences between SI & LI?q

Answer 9

no villi
incomplete layer of longitudinal muscle
-taenia coli
ring like arrangement of circular muscle
-haustrae

Question 10

describe the absorption function of the LI

Answer 10

0.5-1.0 L chime enters LI from ileum
LI reabsorbs fluid and electrolytes from SI chime
failure to reabsorb=diarrhoea

Question 11

what are intestinal flora?

Answer 11

resident microbial populations
roles:
-ferment dietary fibre & lipid
-gases produced
-synthesise some vitamins:
vit. B complex, vit. K

Question 12

describe LI motility

Answer 12

mixing movements
similar to segmentation in SI
contraction of circular muscles
squeezing action of chime
mainly in caecum & ascending colon
propulsive movements

Question 13

what is peristalsis?

Answer 13

short range in transverse and descending colon

propels semi-solid faecal matter towards rectum

Question 14

what are mass movements?

Answer 14

infrequent, more sustained contractions
usually after meals
moves chime/faeces from proximal to distal colon
rectal distension associated with desire to defaecate

Question 15

describe defaecation

Answer 15

ejection of faecal matter from rectum via anal canal
involuntary reflex
rectum & internal sphincter SM controlled by ANS
external is striated

Question 16

what is an ileostomy?

Answer 16

ileum brought out towards skin- stoma

Question 17

what is a colostomy?

Answer 17

colon brought out

Question 18

describe diarrhoea

Answer 18

excessively watery stools
mainly GIT infections
failure of fluid absorption
reduced colonic motility
less mixing
less fluid absorption
results:
dehydration
electrolyte imbalance

Question 19

describe constipation

Answer 19

characterised by hard faeces, difficult to pass
due to increased fluid absorption
associates with GIT spasm
side effect of some drugs 
role of dietary fibre