Large intestine structure and function

Question 1

what is a feature of the muscularis externa in the colon?

Answer 1

the circular muscle is complete but the longitudinal muscle is incomplete

Question 2

what are the bands which run in the middle of the colon and how many of them are there?

Answer 2

there are 3 tenure coli which run the length of the colon

they are discontinuous which is why there are 3 separate ones

Question 3

what feature in the colon is responsible for producing lubrication for movement of faeces?

Answer 3

large straight crypts lined with goblet cells

Question 4

what part of the large intestine has the thickest muscularis externa?

Answer 4

the anal canal

Question 5

what is the main difference between the internal and external sphincter of the anal canal?

Answer 5

internal is smooth muscle

external is skeletal muscle

Question 6

what is the epithelium of the anal canal?

Answer 6

goes from simple columnar to stratified squamous

Question 7

what are the symptoms associated with constipation?

Answer 7

nausea
headaches
abdominal distension
loss of appetite

Question 8

what are the causes of diarrhoea?

Answer 8

pathogenic bacteria i.e. e.coli, vibrio cholera
protozoans
viruses
toxins
food
stress

Question 9

how do enterotoxigenic bacteria cause diarrhoea?

Answer 9

they produce protein enterotoxins which turn on intestinal Cl secretion from crypt cells.
this results in a lot of water secretion as it follows the Cl

Question 10

enterotoxigenic bacteria act by elevating intracellular messengers such as?

Answer 10

cAMP
cGMP
calcium

Question 11

what is the treatment for diarrhoea?

Answer 11

oral rehydration therapy

- Na/glucose solution which drives water absorption