Small &

Gastrointestinal block--Lecture 6,7

Editing file Objectives Color guide : Only in boys slides in Green Only in girls slides in Purple important in Red At the end of the lecture, students should be able to: Notes in Grey ● List the different parts of . ● Describe the anatomy of , & regarding: (the shape, length, site of beginning & termination, peritoneal covering, arterial supply & lymphatic drainage) ● Differentiate between each part of duodenum regarding the length, level & relations. ● Differentiate between the jejunum & ileum regarding the characteristic anatomical features of each of them. ● List the different parts of large intestine. ● List the characteristic features of colon. ● Describe the anatomy of different parts of large intestine regarding: (the surface anatomy, peritoneal covering, relations, arterial & supply) Small intestine The small intestine divided into :

Fixed Part (No ): Free (Movable) Part (With Parts Duodenum* Mesentery): Jejunum & Ileum

Shape C-shaped loop coiled tube

Length 10 inches 6 meters (20 feet)

Transverse Colon separates the Beginning At pyloro-duodenal junction at duodeno-jejunal flexure / from the jejunum/ileum

Termination At duodeno-jejunal flexure at ileo-ceacal flexure

Peritoneal Covering Retroperitoneal mesentery of small intestine

Divisions 4 parts ------

Foregut (above duct opening in 2nd part )& Embryological origin Midgut (below opening in 2nd part) So 2nd part has double origin and double supply

Coeliac ( of ) Superior mesenteric Arterial Supply Superior Mesenteric (artery of midgut)

Lymphatic Drainage Coeliac & Superior Mesenteric Superior mesenteric

3 * 1st inch of 1st part has an omentum with the stomach Duodenum parts

1st Part 2nd Part 3rd Part 4th Part Part ( Superior ) (Descending) (Horizontal) (Ascending)

Length 2 inches 3 inches 4 inches 1 inch

Ascends from L3 Level L1 (Transpyloric Plane) Descends from L1 to L3 L3 (Subcostal Plane) 1 to L2 4 2 1) Liver Anterior 1) Small intestine Liver 2) Small intestine Relations 2) Superior mesenteric vessels 3) Small Intestine 3

1) Bile duct 1) Right psoas major Posterior 2) Gastroduodenal artery* 2) Inferior vena cava Right Left psoas major Relations 3) Portal 3) Abdominal aorta 4) Neck of 4) Inferior mesenteric vessels

Medial - head of Pancreas - - Relations

Lateral - Right Colic Flexure - - Relations

● Opening of accessory One inch higher), on summit of Openings of the 2nd ● Common opening of bile duct & main pancreatic duct On summit of (vater) part the bile duct could be obstructed in case of head of pancreas carcinoma

4 *if there is an ulcer in the duodenum, Gastroduodenal artery will be the source of bleeding Comparison Between Jejunum & Ileum

Jejunum Ileum

Length Shorter (Proximal 2/5) Longer (Distal 3/5)

Diameter Wider Narrower

Wall Thicker (More Plicae Circulares) Thinner (Less Plica Circulares)

Appearance Dark Red (More Vascular) Light Red (Less Vascular) The absorption happen in Jejunum more, so it need to be Vessels Less Arcades (Long Terminal More Arcades (Short Terminal wider and thicker to increase the surface area of Branches) Branches) absorption, also it need to be more vascular to facilitate moving of substance to the circulation Mesenteric Small Amount away from Large Amount Near Intestinal Intestinal Border Border While Ileum is longer and thinner, so it need more fat in Fat around to support it and this fat need supply, so it will be hard for the blood to reach the illem so the vessels need Lymphoid Few Aggregations Numerous Aggregations to be More Arcades to penetrate the fat and supply it. As Tissue (Peyer’s Patches) result of that the blood that reach the ileum will be less so its less vascular

5 Large Intestine

Parts of Large Intestine Characteristics of COLON Peritoneal covering

Parts With Mesentery In Taeniae coli - (in right iliac region ) 3 longitudinal muscle bands 1. Transverse colon (transverse mesocolon) - (in right iliac region ) 2. (sigmoid mesocolon) - (in right lumbar region ) Sacculations (Haustra) 3. Appendix (mesoappendix) - Transverse Colon (in 4,5,6 regions ) Because the Taeniae coli are shorter 4. Cecum (could be without) (see slide 8) - (in left lumbar, iliac regions ) than large intestine Retroperitoneal Parts

In pelvis Epiploic Appendices 1. Ascending colon -sigmoid Colon (in left iliac, hypogastric regions ) 2. Descending colon Short peritoneal folds filled with fat - (in right iliac region ) 3. Upper ⅔ of rectum NOTE:THESE CHARACTERISTICS ARE NOT Parts Devoid Of In FOUND IN RECTUM & Peritoneal Covering 1. Lower ⅓ of rectum

-anal Canal 2. Anal canal

Rectum

Anal canal 6 1 Cecum–ascending & Descending Colons

Parts Cecum Ascending colon Descending colon 1 Coils of small Anterior Relations 1- 2-Coils of small intestine 3-Anterior intestine

1. Right Psoas 1. Right Iliacus 1. Left Iliacus major 2. Right Quadratus 2. Left Quadratus lumborum 2. Right Iliacus lumborum 3. Left kidney. Quadratus kidney : (all right)* 3. Right kidney. 4. Left Psoas major lumborum Posterior Relations Iliohypogastric Nerves: (all right)* Nerves: (all left)* Ilioinguinal lateral cutaneous of thigh Iliohypogastric ,Ilioinguinal, lateral Psoas Iliacus major ,Femoral,Genitofemoral cutaneous of thigh Femoral, Genitofemoral; 2 Transverse Colon

Superior

Anterior Relations Posterior Relations Superior Relation Inferior Relation Anterior

1-greater omentum 1-2nd part of duodenum 1-liver 1-coils of small intestine 2-anterior abdominal wall 2-pancreas 2- 3-superior mesenteric 3-stomach Posterior vessels Inferior 3 Colic Flexures ❖ Hepatic flexure (right colic flexure): position: lower(liver push it down) + angle: wider ❖ Splenic flexure (left colic flexure): Position: higher + Angle: more acute 7 *from the picture in the lecture 4 Appendix 5 Rectum

● the base of appendix is marked Beginning by Mc’Burney’s point: Surface ● A point at the junction of as a continuation of sigmoid colon at level of S3 anatomy lateral ⅓ & medial ⅔ of a line ● traced from right anterior superior iliac spine to umbilicus Termination

At posteromedial aspectof cecum, 1 inch below continues as anal canal, one inch below & in front of tip of coccyx. Opening ileo-cecal junction Its end is dilated to form the rectal ampulla.

1.Retrocecal:(most common) Length 2.Pelvic 3.Subcecal Positions 4.Preilieal 13 cm(5 inches) 5.Postileal:(least common) if the appendix in any position rather than (1) the cecum Relations of Rectum in Pelvis will be without mesentery Vs. Males Females Anterior : Anterior : 1.Posterior surfaces of urinary 1.posterior wall of vagina bladder 2.Seminal vesicles 3.Prostate gland

Rectum Relations of Rectum in Pelvis Posterior: 1.Sacral plexus 2.Sacrum 3.Coccyx 8 Relation between embryological origin of GIT & Supply

Arterial Supply

1-Foregut: 2-Midgut (endoderm) : 3- (endoderm): 4-Ectoderm: celiac trunk Superior mesenteric artery Inferior mesenteric artery inferior rectal artery Includes Stomach ,liver, Includes the Rest of Left ⅓ of transverse colon, Lower part of anal canal gallbladder, pancreas, , duodenum ,jejunum, ileum, descending colon, sigmoid upper part of duodenum until cecum,appendix, ascending colon, rectum, upper part of major duodenal ampulla colon, right ⅔ of transverse anal canal colon

Venous Drainage Lymph drainage of GIT Nerve Supply

● draining gut form the portal circulation ● The lymph vessels follow the . ● Midgut (endoderm) : Autonomic nerve ● All veins finally end into portal vein ● Ultimately, all the lymph is collected at supply :Sympathetic + the Preaortic lymph nodes (Superior & which enters the liver ● Inferior mesenteric). ● Hindgut (endoderm) Autonomic nerve supply :Sympathetic + pelvic (S2,S3,S4) ● ● ectoderm(lower ⅓ of anal canal) Somatic nerve supply :inferior rectal (branch of pudendal nerve)

9 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8

QUIZ 1 D C C B A B D B

Q1: The duodenum originates from the ……. Q5: What part of the duodenum lies in the transpyloric plane? A. Foregut A. 1st B. Midgut B. 2nd C. Hindgut C. 3rd D. A&B D. 4th Q2: Which of the following could be injured in case of perforated duodenal ulcer? Q6: the length of the Jejunum & Ileum is A. Right kidney A. 6 inches B. Right colic flexure B. 6 meter C. Gastroduodenal artery C. 10 meter D. Inferior mesenteric vessels D. 10 inches Q3: if there is a stone in gallbladder ,Which part of intestine initially receives the stone? Q7: :Which one of these contains numerous aggregation of Lymphoid Tissue ? A. cecum A. Jejunum B. ascending colon B. Stomach C. 2nd part of duodenum C. duodenum D. 3rd part of duodenum D. ileum Q4: Which of the following lies anterior to the third part of duodenum? Q8: Which ONE of the following lies behind the 3rd part of the duodenum? A. Right psoas major A. inferior mesenteric vein B. Small Intestine B. inferior mesenteric artery C. Ureter C. superior mesenteric artery D. Bile duct D. Gastroduodenal artery 10 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8

QUIZ 2 B C A C C B A D

Q1: where does the rectum begin? Q5: One of the superior relations to transverse colon is A. At s3 as continuation of cecum A. Coils of small intestine B. At s3 as continuation of sigmoid colon B. Anterior abdominal wall C. At L3 as continuation of cecum C. Gallbladder D. At L3 as continuation of sigmoid colon D. Right kidney Q2: which one of the following structures found in pelvis? Q6: if superior mesenteric artery and vagus nerve injured. Which part of colon will be affected? A. Anal canal A. Ascending and descending B. Descending colon B. Ascending and transverse C.sigmoid colon C. Descending and sigmoid D.appendix D. Descending and transverse Q3: which one of the following structures marked by Mc’Burney’s point? Q7: Appendix opens at posteromedial aspect of cecum, ……below ileocecal junction A. Base of appendix A. 1 inch B. Apex of appendix B. 5 inches C. Beginning of cecum C. 3 inches D. Termination of cecum D. 2 inches Q4: the innervation of inferior part of anal canal is : Q8: One of anterior relations of rectum in males is A. Autonomic,by vagus nerve A. Vagina B. Somatic, by pudendal nerve B. Sacral plexus C. Somatic ,by inferior rectal nerve C. Sacrum D. Autonomic, by pelvic splanchnic nerve D. Posterior surfaces of urinary bladder 11 Members board Team leaders ● Abdulrahman Shadid ● Ateen Almutairi

Boys team: Girls team :

● Mohammed Al-huqbani ● Ajeed Al Rashoud ● Salman Alagla ● Taif Alotaibi ● Ziyad Al-jofan ● Noura Al Turki ● Ali Aldawood ● Amirah Al-Zahrani ● Khalid Nagshabandi ● Alhanouf Al-haluli ● Sameh nuser ● Sara Al-Abdulkarem ● Abdullah Basamh ● Renad Al Haqbani ● Alwaleed Alsaleh ● Nouf Al Humaidhi ● Mohaned Makkawi ● Jude Al Khalifah ● Abdullah Alghamdi ● Nouf Al Hussaini ● Danah Al Halees ● Rema Al Mutawa ● Maha Al Nahdi ● Razan Al zohaifi ● Ghalia Alnufaei

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