What are the segments of the large intestine?
Cecum, colon, and rectum
What is a cecum?
A blind diverticulum of the colon that is more functional in herbivores and is the site of bacterial fermentation
What are the components of the colon?
Ascending, transverse, and descending
How much of the GI length is comprised by the colon?
20-25% total length
What are the layers of the large intestine?
Mucosa- submcosa- muscularis- serosa
T/F: The large intestinal mucosa possesses villi but no goblet cells.
False
Mucosal layer of the LI does not have villi but has many mucus secreting cells
What are crypts of Leiberkuhn?
How long is the cell turnover rate in the large intestine compared to the small intestine?
4-7 days
Slower than the SI
What are the functions of the large intestine?
What is the function of the mucus and bicarbonate secretion function of the large intestine?
What are clinical signs of colonic disease?
Diarrhea OR constipation Blood in or on the stool Mucus on stool Tenesmus Dyschezia Urgency
No weight loss or vomiting usually unless severe disease (more common in cats)
What are some potential physical exam findings in a patient with colonic disease?
Typically normal
Anal or peri-anal irritation
Weight loss in advanced disease
Dehydration or fever
Constipation
Must assess for hind end neurologic disease
What may you find on a rectal palpation in an animal with colonic disease?
What are some general disease processes found in the colon?
What can you find on CBC that can help you characterize colonic disease?
What serum chemistry findings can help you characterize colonic disease?
What are radiographs useful for when assessing colonic disease?
Obstructions, constipation, megacolon, masses, lymphadenopathy
Negative contrast colonogram for intraluminal masses
What is the importance of assessing the sublumbar LN in colonic patients?
Enlarged sublumbar LN can compress the rectum leading to obstruction and constipation in an otherwise healthy gut
What can be assessed on ultrasound of the large intestine?
When would MRI or CT be approriate?
Evaluation of intrapelvic structures- distal colon, rectum, and anal canal
When is a colonoscopy useful?
What is the prep required for a colonoscopy?
What does a normal colon look like?
Pink, smooth, glistening with frequent peristalsis
What parasites can you find in the colon?
Trichuris vulpis Heterobilharzia americana Tritrichomonas foetus Giardia Histoplasmosis Pythium