Large intestine

M.Team
Site Admin
Posts: 34
Joined: Wed Jul 06, 2016 3:43 pm
Contact:

Re: Large intestine

Postby M.Team » Fri Aug 05, 2016 9:17 pm

Axial twisting of the right colon or cecal volvulus has been shown to be associated with each of the following except:
A. A history of abdominal operation.
B. A mobile cecum.
C. An obstructing lesion in the transverse or left colon.
D. Inflammatory bowel disease.
Answer: D

DISCUSSION: Volvulus of the right colon is less common than sigmoid volvulus and may involve either an axial twist of the right colon or a cephalad fold of the cecum (cecal bascule). A mobile cecum is a prerequisite for cecal volvulus and may occur in up to one third of individuals. Cecal volvulus has also been called postoperative volvulus because of its tendency to follow abdominal surgical procedures. Obstructing lesions in the distal colon may lead to distention and torsion of the right colon in patients with abnormalities of cecal fixation.

M.Team
Site Admin
Posts: 34
Joined: Wed Jul 06, 2016 3:43 pm
Contact:

Re: Large intestine

Postby M.Team » Fri Aug 05, 2016 9:55 pm

Sigmoid volvulus has been associated with each of the following except:
A. Chronic constipation and laxative abuse.
B. Chronic rectal proplapse.
C. Chronic traumatic paralysis.
D. Medical management of Parkinson's disease.
Answer: B

DISCUSSION: The development of sigmoid volvulus depends on the presence of a dilated, redundant sigmoid colon. This acquired redundancy may be secondary to long-term ingestion of a high-residue diet, particularly in parts of the world where the disease is common. In the United States, the most prominent association is chronic constipation and excessive reliance on laxatives or enemas. Other contributing factors include neurologic or psychiatric conditions such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, traumatic paralysis, chronic schizophrenia, pseudobulbar palsy, and senility. Patients are frequently bedridden and are being managed with various neuropsychotropic drugs, both of which may alter bowel motility.

M.Team
Site Admin
Posts: 34
Joined: Wed Jul 06, 2016 3:43 pm
Contact:

Re: Large intestine

Postby M.Team » Fri Aug 05, 2016 9:56 pm

How much of the daily insensible water loss is due to loss in stool?

a. 200 ml
b. 400 ml
c. 600 ml
d. 800 ml
e. 1000 ml
Answer: a

Compared with the small intestine, the epithelium of the colon is relatively impermeable and requires a considerably longer period of time to absorb the salt, water, and carbohydrate presented to it. Between 500 and 1500 g of a semiliquid material enter the colon on a daily basis. Most of this substance is absorbed, yielding a stool output that weighs about 200 g. The reason for this efficient absorptive capacity, despite the relative impermeability of the colonic epithelium, relates to the close interrelation between epithelial transport and colonic motor activity. Transit through the large bowel takes about 10 times as long as that through the small intestine, usually requiring 2 or 3 days. Such slow passage provides optimal opportunity for the luminal contents to come into surface contact with the absorptive epithelium. Thus, sodium and water, which are extracted against high electrochemical and osmotic gradients, are efficiently absorbed. Further, the relatively static conditions of the colon allow the proliferation of vast numbers of anaerobic bacteria, which in turn break down carbohydrate to volatile fatty acids, which then are rapidly absorbed. The more rapid the colonic transit, the less efficient are these absorptive processes.


Return to “Daily questions”

Who is online

Users browsing this forum: amorlerirl, CharlesSem, knomeGet, Seichejib and 1 guest


Get it on Google Play