Small bowel
Anatomy
Small bowel
Length:
75 % of the total length of
GI
260 cm by living persons
5 – 7 m post mortem
Parts:
jejunum
ileum
2/5 length
3/5 length
Anatomy
Wall of small intestine:
1. Serous layer
2. Muscular layer
smooth muscle
3. Submucosa
fibroelastic tissue, blood
and lymphatic vessels
4. Mucosa
Microanatomy
Wall of small intestine:
Circular plices - Kerkring-i enlarge 3 x the surface of mucosa
Villi intestinales
enlarge 10 x enlarge 3 x the
surface of mucosa
Microvilli
enlarge 30 x surface of
mucosa
total enlargement 900 x !!
Epithelium
- enterocytes - absorb cell
- goblet cells – mucin production
Anatomy
Blood supply:
a.mesenterica superior
a. pancreaticoduodenalis inferior - pancreas
duodenum
aa. jejunales
– one arcades- jejunum
aa. ileae
– 2-4 arcades
- ileum
a. ileocolica
– colon ascendens and caecum
a. colica dextra – colon ascendens
a. colica media – colon transversum
Blood supply of small bowel
Bood supply of large bowel
Physiology
digestion:
1. Intraluminal phase:
chymus is mixed with enzymes from enterocytes,
pancreas, bile, stomach
2. Absorb phase : in the wall of bowel
absorbtion of nutrients, water, minerals, vitamins
3. Transport phase
Physiology
Motility:
1. Peristaltic
Circular contractions in distal direction
fr.= 10/min., transit time in small bowel is 1- 6 hr.
2.
Segmental contractions:
to mix the content
Absorbtion
Absorbtion
Mesentery - functions
1.
2.
3.
4.
mechanical support for bowel
blood supply
lymphatic drainage of nutrients
immunological barrier
Physiology
Functional disorder 1. :
Maldigestion – intraluminal disorder
lack of bile, stomach acid, or pancreatic intestinal juice
Malabsorbtion – disorder in the phase of absorbtion
or transport
Physiology
Other functional disorders 2. :
Diarrhea ( osmotic, infection, )
Blind sac sy ( stasis of enteral content in a blind
sac, what leads to bacterial contamination
and deconjugation a of bile acids - diarrhea)
Short bowel sy ( after extent resections, leads
to depletion of water, minerals, nutrients,
vitamins) requires parenteral nutrition
Diagnostics specific
enteroclysis- „small bowel enema“
study
enteroscopy
-
double balloon
push
on table
capsule
Double balloon enteroscopy
Double balloon enteroscopy
Push enteroscopy
PILLCAM - hi-tech
capsule
enteroscopy
Capsule endoscopy
On table enteroscopy- bleeding
from adenoma
Enteroscopy- A-V malformation
Enteroscopy
necrotizing colitis, adenoma
Non specific
Laboratory
X-ray
Ultrasound
CT
MRI
Gastroscopy
Colonoscopy
AG, scintigraphy- bleeding
Plane X-ray
Plane X- ray , lateral
Barium enema
Barium enema study
Barium enema study- MC
Angiography
Exomphalos
Surgical treatment
Meckel´s diverticulum
remnant of omphaloenteteric duct,
which did not obliterate
Pathology : 1-2%, situated on the
antimesenterial site of bowel
Clinical presentation : inflammation,
bleeding, torsion, ileocaecal
invagination
Dg : not easy
Therapy : resection of diverticulum
Meckel´s diverticulum
Ileocoecal
invagination
Mesenterial cysts
Pathology :on the mesenterial site of
bowel,
Symptoms : chronic pain, palpable mass,
can be signs of compression
Dg : X-ray, ultrasound, CT, MRI
Therapy : resection of bowel and mesentery
Mesenterial cyst
Crohn´s disease- IBD
Granulomatous inflammation, which
extends diffusely through the entire
thickness of the bowel wall
Can affect whole GI, but most commonly in small
and large bowel ( skip lesions)
Etiology: not known
Pathology: a/acute inflammation
b/chronic inflammation
c/ complications
Clinical features
Acute- pain, diarrhea, fever
Chronic- malabsorbtion, extraintestinal
Complications: obstruction, fistulas,
bleeding, perforation, perianal MC
Dg :History, examination, barium enema,
endoscopy (cobblestone surface),
ultrasound, CT, biopsy
Ulcerative colitis
Crohn´s disease
Endoscopy
Endoscopy
Endoscopy
Small
bowel
enema
CT
Crohn´s disease
Crohn´s disease
Thickened wall
by inflammatory
oedema
Crohn´s disease
Fissured ulcers
Extraintestinal presentation
Treatment
Dietary : without fiber, avoiding
malabsorbtion, elementary diet.
2. Parenteral nutrition:
3. Drugs
-
5-ASA ( sulphasalazine)
steroids- parenteral, p.o, topical
azathioprin ( IMURAN )
Metronidazol 0,5- 1,5
monoclonal antibodies anti TNF alfa
(Remicade)
Surgical treatment
Urgent–perforation, toxic megacolon, bleeding, obstruction
elective –abscess, fistulas, chronic obstruction
Resection, anastomosis, stoma ,
stricturoplasty
Recurrent disease
Opening
Revision
Resection
Anastomosis
Benign tumors
Rare only 1.5 = of GI tumors
Mostly mesenchymal
Clinical presentation: obstruction, bleeding,
Dg: small bowel enema, endoscopy, ultrasound, CT,
MRI
Therapy: surgical resection with anastomosis
Malignant tumors
Rare only 2% of GI tumors
adenocarcinoma – 50 %,
leiomyosarcoma – 33 %
carcinoid – semimalignant with
metastatic potential
lymphoma
GIST – gastrointestinal stromal tumor
Clinical presentation: obstruction, bleeding,
Dg: small bowel enema, endoscopy, ultrasound, CT, MRI
Therapy: surgical resection with anastomosis
CARCINOID of small
bowel
Carcinoma: source of bleeding
Ischemic small
bowel
Gangrenous
small bowel
Retroperitoneal anatomy