Intestinal disease

• Small intestine measurements taken at autopsy ( cadaver examination ), because of endoscope and coloscope cant reach small intestine (iluem) so its suggests that adult lengths of small intestine between 3 & 9 meters.

Histology of small intestine

• Once we have a duodenal biopsy we have to count lymphocyte, if they are more than 20 mean inflammation

Why ?because the presence of goblet cells ( which secretes mucus along the whole intestines ) is not sufficient to protect the duodenum from the gastric acids .

Brunner’s glands

• tuboalveolar( or tubule-acinar ) glands .

• have ducts that open directly into the crypts of lieberkuhn .

• Has Urogastrone : an enzyme that is secreted to the blood ,it goes to the parietal cells and inhibits their acid secretion .

folding of lamina propria and epithelium

Goblet cells : (uni-cellular ) that secrete mucinogen (mucus precursor ) to lubricate the small intestine

I , S cells

Paneth cells (defense cell) :Apical eosinophilic granules: secrete lysozymes

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Intestinal gland

Paneth cell

• Paneth مع الفرن

Rough endoplasmic reticulum

Basal nuclei

Rich in goblet cells.

• As we going from duodenum to ileum number of lymphocytes are increased

• why ?

• Coz the food will converted to fecal material >> that’s increase number of bacteria>> and should be balance between bacteria and inflammatory cells .

• Atresia : absence of canalization where as stenosis is narrowing of lumen >

• Duodenal Atresia is associated with Down syndromefailure to recanalize(trisomy 21).

there is a reminant of the yolk sac

“persistence”

• Located in distal ileum usually within (2 feet )

• the blend segment or pouch is about (2inch) long.

• most common malformation of GIT (2% of population ).

• true diverticulum its mean that bulging part have 3 layers not 2(false)” more common”.

The complication of this disease are pain and bleeding which may mimicappendicitis therefor , during appendectomy , ileum should be checked for presence of meckel's diverticulum , if it is found to be present itshould be removed with appendix

its role of 2

• Heterotopic rests of gastric mucosa and pancreatic tissue (rare ) .

• heterotopic means displacement of an organ from its normal location

infracolic compartment.

supracolic compartment.

Meckel diverticula may contain ectopic gastric mucosa (which can ulcerate surrounding mucosa with pain and bleeding) or ectopic pancreas (which is of no consequence unless it forms a mass large enough to predispose to intussusception).

“malrotation of midgut”

Volvulus

• Mostly in small intestine; large intestine especially sigmoid and cecum.

• Rare.but

Most common

In adults.

The nervous system in GI has 2 networks (plexuses) of nerves :(Enteric Nervous System):

• 1.Meissener’s submucosal plexus:-

- related to the secretory function.

- it Stimulates the contraction of muscularismucosa and the contraction of the endothelial and other cells in ( glands and blood vessels )

- Neurotransmitter Vasoactive Intestinal Peptides (VIP) and Nitric Oxide (NO) cause the smooth muscle contraction and thus increase blood flow to intestinal epithelium.

• 2. Auerbach’s myenteric plexus قوي =أورباخ

-within the muscularis externa > (between the inner circular and the outer longitudinal >movement.

-They are excitatory , but some are inhibitatory(They secrete (VIP) which inhibit intestinal sphinctre muscles like: pyloric sphinctre & ileocecal valve .

Functional

anatomical

May be associated with other congenital

anomalies like :

1 – hydrocephalus 2 –VSD 3 -Meckel’s

diverticulum

https://www.youtube.com/watch?v=9QjZe6zZpRA

• Classification of diarrheal disorders :-

• 1- Secretory diarrhea :-

-Secretory diarrhea means that there is an increase in the active secretion, or there is an inhibition of absorption.

-There is little to no structural damage

-The most common cause of this type of diarrhea is a cholera toxin that stimulates the secretion of anions,

especially chloride ions. Therefore, to maintain a charge balance in the lumen, sodium is

carried with it, along with water

• 2- Osmotic diarrhea

• occurs when too much water is drawn into the bowels. If a person drinks solutions with excessive sugar or excessive salt, these can draw water from the body into the bowel and cause osmotic diarrhea.

• Osmotic diarrhea can also be the result of maldigestion :(e.g., pancreatic disease or Coeliac disease), in which the nutrients are left in the lumen to pull in water.

• Or it can be caused by osmotic laxatives (which work to alleviate constipation by drawing water into the bowels)

• 3- Exudative diarrhea:-

• Exudative diarrhea occurs with the presence of blood and pus in the stool. This occurs with inflammatory bowel diseases,( bacterial).

• 4- Malabsorption diarrhea :-

• unabsorbed nutrients & fat.

• 5- Deranged motility diarrhea :-

• decreased intestinal retention time; decreased motility. WHY??

• Because it leads to bacterial overgrowth infection diarrhea