sheet no . 36

Small Intestine:

- It is a complete intraperitoneal tube, about 6M in length.
- Extending from duodenojejunal junction to the ileocecal junction.
- It extends from the left side(beginning) to the right side(end) of vertebral column.
- They are anchored to the posterior abdominal wall via fan-shaped double layer of peritoneum called mesentery of small intestine.

- Divided into 2 parts:

1. Jejunum.
2. Ileum.
These parts are known by their specific features,,
--> Jejunum:
* Representing 2/5 of small intestine = 2.5m.
* Larger in diameter.
* Thick in wall.
* Red in color (because of high vascularity; high absorption).
--> Ileum:
* Representing distal 3/5 of small intestine = 3.5m.
* Smaller in diameter.
* Thin in wall.

* Pale in color (less vascularity; no need for efficient absorption; semi-solid food).
- Arterial supply of small intestine: by Superior Mesenteric Artery.
- Venous drainage of small intestine: to the portal vein.

- Location: located around umbilicus, that's why colicky pain from small intestine is usually felt around umbilicus.


Large Intestine:

- Forms a frame around small intestine.
- Consist of:
(1) Appendix.
(2) Cecum (one-way tube).
(3) Ascending colon.
(4) Hepatic angle.
(5) Transverse colon.
(6) Splenic angle.
(7) Descending colon.
(8) Sigmoid colon.
(9) Anal canal and rectum.
- All of it is intraperitoneal except: ascending colon and descending colon, acting as pillars.
* Appendix:
- Intraperitoneal blind tube (highly mobile), with mesentery.
- Longer in children, shorter in old ages, that's why appendicitis is more common in children and young adults.
- Has base, which is fixed, and apex, which is mobile.
- Positions of the tip of appendix (apex):
1) Retrocecal (behind Cecum, as Retro ≡ behind) at 12 o'clock à (64%).
2) Pelvic (in the pelvis) at 6 o'clock à (32%).
3) In the left side at 3 o'clock à (1%).
4) In the right side at 9 o'clock à (2%).

♣NOTE:
- Below appendix we have the femoral nerve, so a patient with appendicitis:
• who is flexing his hip as he couldn't extend it because that will irritates the femoral nerve causing pain --> Retrocecal Appendicitis.

• who has problems in urination, problems in uterus or ovary in female, and constipation or diarrhea --> Pelvic Appendicitis.

- Appendicitis is less common in old ages also because the appendix is transferred into fibrous tissue in old adults [Atrophy], and it's shorter.
- By a line extending from anterior superior iliac spine to umbilicus, we can allocate the base of appendix : at the point between the medial 2/3 and the lateral 1/3.

* Cecum:
- Intraperitoneal blind tube.
- Located in the right iliac fossa (over iliacus).
- Recieves ileum, and gives appendix and ascending colon.

♣ It is the site involved in constipation, so any problem of constipation will affect iliacus and femoral nerve, and vice versa.

* Ascending colon:

- Retroperitoneal.
- Close to right kidney and right ureter (in the right lumbar region).

* Hepatic angle (Right angle):

- Between ascending and transverse colon.
- It is related to visceral surface of liver (in the right hepatic region).

* Transverse colon:

- Intraperitoneal.
- Extending from hepatic angle to Splenic angle ( from liver to spleen).
-->Proximal 2/3 is supplied by Superior Mesenteric Artery.
--> Distal 1/3 is supplied by Inferior Mesenteric Artery.

*splenic angle:

- higher in position than the hepatic angle, that's why gases are collected in the splenic angle, causing pain in the left side of abdomen that is exaggerated when the patient is standing and fades when he lies on his back.

* Descending colon:

- Retroperitoneal.
- Related to left kidney and left ureter (in the left lumbar region).

* Sigmoid colon:
- S-shaped tube.
- Intraperitoneal.
- located in the left iliac fossa.

** Cecum is located in the right iliac fossa, opposite to it is the sigmoid colon in the left iliac fossa.
* Specific features of Large intestine
--> Haustra (Sacculation); bulges.

They are the site of fermentation of fibers by a bacteria located there.
• Crohn's Disease is caused by the laze of mucosa of the GI tube.



"Education is replacing closed minds with opened ones..."

Sawsan Tabaza . .
I'd like to dedicate this sheet to all my friends, especially:
Sondos Alkhatib (Sannnoon), Ruba Almohtaseb (Apple vs. Carrot :D), Lama Jamal (kf o ana a3rf :p,, o a5eran.. Mabroook Elro5sa :D !!!), Aya Bni-Kenanah:D, Samar Alrahmeh (J), Nisreen Abu-osbeh, Haneen Shraideh, Dania Dahmsh, Ruba Halaseh, Shatha Atteli, Waed Swaelmeen, Suzan Mbaydeen, Jamela, Najd Quraan, Rawan Saleh, Zein, Ala' abd alra'ouf, Bayan Alkhdoor, Rasha Jabra, Aseel.

And to all my colleagues.
Special thanks for: Yezan 3toom, Ahmed Abu-khadigh, and Hamza Jassar.