Class Notes (811,170)
Canada (494,539)
Physiology (885)
PHGY 313 (80)

19- Crohn's and Hirschprung's.docx

5 Pages
Unlock Document

McGill University
PHGY 313
Russell Jones

Crohn's and Hirschprung's Disease Crohn's Disease Symptoms: abdominal pain in central and right lower quadrant. Diarrhea, weight loss, and lassitude. Required iron supplements and intramuscular injections of vitB12. Eventually got intestinal obstruction and had parenteral nutrition. Developed gallstone disease later. 1. What is the basic defect in Crohn's disease and which parts of the GI tract are affected? Expand on the function of the different segments on the intestinal tract on the absorption of different nutrients. Crohn's disease is an autoimmune disease causing inflammation of the SI. All parts of the GI tract can be affected from the mouth (aphthous ulcers of mucosa and tongue) to anus (skin tags, fistulas). The main affected area is the terminal ileum, but in the intestines many things occur:  Thickening of walls (obstruction)  Fibrosis  Cobble stone mucous membrane  Mesenteric lymph nodes enlarge (Peyer's patches in jejenum)  Granulomas Note: Vitamin B12, vitamin C, and bile salts are absorbed in the ileum. B12 is important for the production of healthy RBCs and bile salts are important for fat absorption. 2. Why did the patient suffer from weight loss and tiredness? Damage to the small intestine can cause fibrosis and damage of enterocytes, leading to malabsorption of fat, carbohydrates, vitamins, and minerals. A fistula can cause a bypass of some of the small intestine leading to further malabsorption. This leads to weight loss and fatigue. The patient is also anemic and tired. 3. Why injections of B12 and iron were given? The terminal ileum was damaged and chronic gastrointestinal bleeding leads to iron deficiency anemia so iron must be injected. B12 is also absorbed here so it must be injected as well. 4. What could be the cause of gall stone disease in this patient? Bile salts are mainly absorbed in the terminal ileum. With it damaged, there is no recycling of bile salts and the liver can't keep up with de novo synthesis of conjugated bile salts. Micelle formation is impaired and cholesterol precipitates out, creating a gall stone. Questions: Colon bacteria, motility of SI, laxatives, defecation reflex Overview of small intestine (6.5m in vivo, 7.5m after death because loss of muscle tone)  Duodenum is 25cm. Has intestinal glands like crypts of lieberkuhn and glands of Brunner  Jejunum=2.5m and ileum is 3.75m with anatomical separation. The microvilli are smaller, and have Peyer's patches (contain immune cells like macrophages). They are on a mesentery (double layer of peritoneum separating the jejunum and ileum from posterior wall of abdomen)  Superior mesenteric artery feeds the SI o Blood flow is about 10% of cardiac output, but increases 50-300% during a meal. o Controlled by nerves (vagus), hormones, and paracrine factors o Drains into portal veins  Microvilli increase area which increases permeability as in Fick's equation o Has a venule, an arteriole, and lacteal Motility Function: mixes digestive juices with chyme and moves contents to colon 1. Spontaneous contractions a. Due to uneven amplitude of the oscillating MP, b. Influenced by ACh and stomach contractions c. 12x minute (tonic), contracts even if no food present 2. Migrating myoelectric complex MMC a. Triggers every 1.5h that lasts 10min b. Contraction of the whole intestine aborally (toward colon) c. Occurs even when not in a meal Segmentation tries to mix the food in the SI Peristalsis a wave that pushes the chyme down, a propagating wave Motility results from:  Stretch  Intrinsic nerves of intramural plexus  Extrinsic auton
More Less

Related notes for PHGY 313

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.