Gross Anatomy Of Small Intestine

Question 1

•The small intestine is an organ located within the ————.
•Primary function is to ——-
• It extends from the ——-to the ——-, where it meets the large intestine.
•Anatomically, the small intestine (small bowel) can be divided into three parts; the ——-, —— and ——.

Answer 1

•The small intestine is an organ located within the gastrointestinal tract.
•Primary function is to absorb the nutrients and minerals found in food (chyme)
• It extends from the pylorus of the stomach to the iliocaecal junction, where it meets the large intestine.
•Anatomically, the small intestine (small bowel) can be divided into three parts; the duodenum, jejunum and ileum.

Question 2

DIMENSIONS AND SIZE OF THE SMALL INTESTINE The average length of the small intestine in an adult human male is — m. (—- ft — in)
—- m (—ft — in) in an adult female.
It is smaller in width than the large intestine and can be differentiated from it by the absence of —-, —— and ——— which are present on the surface of the large intestine.
It can vary greatly, from as short as ——m (15 ft) to as long as —— m (32 ft).
Recent studies indicate that small intestine may be shorter, around —- m (— ft— in), and that the length is less affected by age after childhood than expected
It is approximately —- to — cm in diameter.
The surface area of the human small intestinal mucosa averages ——

Answer 2

DIMENSIONS AND SIZE OF THE SMALL INTESTINE The average length of the small intestine in an adult human male is 6.9 m. (22 ft 8 in)
7.1 m (23 ft 4 in) in an adult female.
It is smaller in width than the large intestine and can be differentiated from it by the absence of tenia coli, haustrations and appendices epiploicae which are present on the surface of the large intestine.
It can vary greatly, from as short as 4.6 m (15 ft) to as long as 9.8 m (32 ft).
Recent studies indicate that small intestine may be shorter, around 3.5 m (11 ft 6 in), and that the length is less affected by age after childhood than expected
It is approximately 2.5–3 cm in diameter.
The surface area of the human small intestinal mucosa averages 30 square meter

Question 3

• The small intestine is divided into three structural parts.
• The Duodenum: The shortest, widest and most fixed part of the small intestine.
• It extends from the ——to the ——. It is ‘—’ or —- shaped.
• Approximately —-cm in length curved around the ——- and is mostly retroperitoneal except for its ——

Answer 3

• The small intestine is divided into three structural parts.
• The Duodenum: The shortest, widest and most fixed part of the small intestine.
• It extends from the pyloric end of stomach to the duodeno jejunal flexure. It is ‘C’ or horse shaped.
• Approximately 25 cm in length curved around the head of the pancreas and is mostly retroperitoneal except for its two ends.

Question 4

PARTS OF THE DUODENUM
The duodenum is composed of 4 parts
The 1st superior part, about —- cm(—in) long
The 2nd or descending part, about —cm (—in) long,
The 3rd or horizontal part, about —- cm (—in) long
The 4th or ascending part, about —- cm (—in) long

Answer 4

PARTS OF THE DUODENUM
The duodenum is composed of 4 parts
The 1st superior part, about 5 cm(2in) long
The 2nd or descending part, about 7.5cm(3in) long,
The 3rd or horizontal part, about 10 cm(4in) long
The 4th or ascending part, about 2.5 cm(1in) long

Question 5

List the parts of the duodenum

Answer 5

Superior
Descending
Transverse/horizontal
Ascending

Question 6

STRUCTURE OF THE SMALL INTESTINE
• It receives gastric chyme from the stomach, together with
digestive juices from the —- (digestive enzymes) and the —— (bile).
• The digestive enzymes break down proteins and bile and emulsify fats into ——.
• The duodenum contains —— glands, which produce a mucus-rich alkaline secretion containing bicarbonate. These secretions, in combination with bicarbonate from the pancreas, neutralizes the stomach acids contained in gastric chyme.

Answer 6

STRUCTURE OF THE SMALL INTESTINE
• It receives gastric chyme from the stomach, together with
digestive juices from the pancreas (digestive enzymes) and the gall bladder (bile).
• The digestive enzymes break down proteins and bile and emulsify fats into micelles.
• The duodenum contains Brunner’s glands, which produce a mucus-rich alkaline secretion containing bicarbonate. These secretions, in combination with bicarbonate from the pancreas, neutralizes the stomach acids contained in gastric chyme.

Question 7

PARTS OF THE
DUODENUM
Superior (L—)
The first section of the duodenum (also called the —- ) is about —-cm in length. It lies —— to the body of the L—- vertebra.
It ascends upwards from the pylorus of the stomach, and is connected to the undersurface of the liver by the ——- ligament
. This area is most common site of duodenal ——-.

Answer 7

PARTS OF THE
DUODENUM
Superior (L1)
The first section of the duodenum (‘the cap’) is about 5cm in length. It lies anterolateral to the body of the L1 vertebra.
It ascends upwards from the pylorus of the stomach, and is connected to the undersurface of the liver by the hepatoduodenal ligament
. This area is most common site of duodenal ulceration.

Question 8

The first part of the duodenum

Peritoneal relations
⦿The proximal 2.5 cm is (movable/immovable?). It is attached to the — omentum above, and to the —- omentum below.
⦿The distal 2.5 cm is (fixed/not fixed?). It is (retroperitoneal/intraperitoneal?).
⦿It is covered with peritoneum only on its ——- aspect.
Visceral Relations
⦿Anteriorly: ——-
⦿Posteriorly: ——
⦿Superiorly: ——-
⦿Inferiorly: ———

Answer 8

Peritoneal relations
⦿The proximal 2.5 cm is movable. It is attached to the lesser omentum above, and to the greater omentum below.
⦿The distal 2.5 cm is fixed. It is retroperitoneal.
⦿It is covered with peritoneum only on its anterior aspect.
Visceral Relations
⦿Anteriorly: Quadrate lobe of liver and gall bladder
⦿Posteriorly: Gastroduodenal artery, bile duct and portal vein and inferior vena cava
⦿Superiorly: Epiploic foramen
⦿Inferiorly: head and neck of the pancreas.

Question 9

Parts of the duodenum

The second part, the descending part descends along the —— sides of the L—to L—vertebrae.
It is (retroperitoneal/intraperitoneal?) and is the most (fixed/not fixed?) part of the duodenum.
It begins at the —— to run vertically for a distance of —— cm to the lower border of the —- lumbar vertebra where it continues with the 3rd part at the ——.
It is related medially to the ——,—-and —- and laterally to the ——,——,——.
It rests on the anterior surface of the medial border of the ——, ——,——-muscle and the ———vessels.
Related Anteriorly by ——
The upper part develops from —gut, while the lower part develops from—gut

Answer 9

The second part, the descending part descends along the right sides of the L1-L3 vertebrae.
It is retroperitoneal and is the most fixed part of the duodenum.
It begins at the superior duodendal flexure to run vertically for a distance of 7.5 cm to the lower border of the 3rd lumbar vertebra where it continues with the 3rd part at the inferior duodendal flexure.
It is related medially to the head of pancreas, main pancreatic duct and bile duct and laterally to the right colic flexure, ascending colon, right lobe of the liver .
It rests on the anterior surface of the medial border of the right kidney, right ureter, right psoas major muscle and the right renal vessels.
Related anteriorly by the fundus of the gallbladder

The upper part develops from foregut, while the lower part develops from midgut

Question 10

PARTS OF THE DUODENUM
⦿ The Third part, — cm in length, extends from the ——-horizontally across the ——- to the ——, where it ends by joining the 4th part infront of the ———.
⦿ Is crossed anteriorly by the ——- vessels.
Relations
Anterior:——-
Posterior:——
Superior:——-
Inferior:———

Answer 10

PARTS OF THE DUODENUM
⦿ The Third part, 10 cm in length, extends from the inferior duodendal flexure horizontally across the inferior vena cava to the abdominal aorta, where it ends by joining the 4th part infront of the abdominal aorta.
⦿ Is crossed anteriorly by the superior mesenteric vessels.
Relations
Anterior: root of mesentery, SMA vessels, coils of jejunum
Posterior: right ureter, right psoas muscle, IVC, abdominal aorta
Superior: Head of pancreas
Inferior: coils of jejunum

Question 11

The major duodenal papilla is a bout —— the length of the descending part of the duodenum

Answer 11

Half way
3.75 cm

Question 12

The major duodenal papilla is — cm away from the pylorus

Answer 12

8.75

Question 13

The minor duodenal papilla is — cm superior to the major duodenal papilla
Therefore the minor duodenal papilla is —- cm away from the pylorus

Answer 13

2cm
6.75cm

Question 14

Another name for accessory pancreatic duct and major pancreatic duct respectively

Answer 14

Duct of santorini
Duct of wirsung

Question 15

Parts of duodenum

The Fourth part, (Ascending (L— to L—)) —-cm long is the shortest part of the duodenum. It ascends from the 3rd part of duodenum infront of and to the left of the ——- to the ——— which lies ——cm to the left of the midline at the level of L2 vertebra.
Relations
Anterior:
Posterior:

Answer 15

The Fourth part, (Ascending (L3-L2)) 2.5 cm long is the shortest part of the duodenum. It ascends from the 3rd part of duodenum infront of and to the left of the abdominal aorta to the duodenojejunal flexure which lies 2.5 cm to the left of the midline at the level of L2 vertebra.
Relations
Anterior: beginning of the root of mesentery
Posterior: left border of the aorta, left psoas

Question 16

The Duodenojejunal flexure is marked by

Answer 16

Ligament of trietz also called suspenseful muscle of duodenum

Question 17

The Suspensory muscle of Duodenum also called the ———— is a fibromuscular band that extends from the ——— behind the —— to be attached to the duodenojejunal flexure at its —— part.
⦿ Contraction of this muscle widens the angle of the flexure, and aids movement of the intestinal contents into the jejunum.

Answer 17

The Suspensory muscle of Duodenum also called the Ligament of Treitz is a fibromuscular band that extends from the right crus of diaphragm behind the pancreas to be attached to the duodenojejunal flexure at its posterior part.
⦿ Contraction of this muscle widens the angle of the flexure, and aids movement of the intestinal contents into the jejunum.

Question 18

The mucous membrane of the duodenum presents circular folds called——,absence of these folds is in the —-

Answer 18

Plica circularis or folds of kerckring
Duodenal bulb

Question 19

————, an arch above major duodenal papilla

Answer 19

Arch of plica circularis or monk’s hood

Question 20

Plica longitudinaris extends inferiorly from ——

Answer 20

Major duodenal papilla

Question 21

DISTINGUISHING FEATURES OF THE DUODENUM

Major distinguishing feature is the presence of ———glands in the submucosa where most of the breakdown of food in the small intestines occurs.
⦿ Mucous cells of these glands produce an ——- secretion
⦿ Also, the point of entry for the bile and pancreatic ducts exhibits fingerlike or leaflike ——
⦿ Few —— cells

Answer 21

Major distinguishing feature is the presence of duodenal (Brunner’s) glands in the submucosa where most of the breakdown of food in the small intestines occurs.
⦿ Mucous cells of these glands produce an alkaline secretion
⦿ Protects the duodenal lining from the acidity of the chyme
⦿ Raises the luminal pH to the optimum level for pancreatic enzyme activity
⦿ Also, the point of entry for the bile and pancreatic ducts exhibits fingerlike or leaflike villi
⦿ Few goblet cells

Question 22

Duodenal ulcer is the erosion of the —- of the duodenum

Answer 22

Mucosa

Question 23

The most common causes of duodenal ulcers are ——- and ——-

Answer 23

Helicobacter pylori and chronic NSAID therapy

Question 24

A duodenal ulcer can give rise to some serious complications if the duodenal wall is perforated:

Answer 24

• inflammation of the peritoneum(peritonitis)- causing damage to the surrounding viscera, such as liver, pancreas, and gallbladder
  -erosion of the gastroduodenal artery-causing haemorrhage and potential hypovolaemia shock

Question 25

Bleeding of the GIT
In an endoscopy, bleeding above the ligament of Treitz is called ——- while below the ligament of Treitz is called——

Answer 25

Upper GI bleed
Lower GI bleed

Question 26

Arterial supply of duodenum

Answer 26

-Superior and inferior pancreaticoduodenal artery form anastomosis around the duodenum
-supraduodenal artery of wilkie
-gastroduodenal artery( branch of the gastroduodenal artery)

Question 27

Venous drainage of the duodenum

Answer 27

Have similar names as the arteries
Drain into splenic, superior mesenteric and portal vein

Question 28

Innervation of the duodenum

Answer 28

Vagus nerve- parasympathetic
T6 to T9- sympathetic

Question 29

Lymphatic drainage of the duodenum

Answer 29

Pancreaticoduodenal nodes

Question 30

Commonest source of bleed in the duodenum is the

Answer 30

Gastroduodenal artery

Question 31

Jejunum and Ileum
⦿ The jejunum and ileum are the distal two parts of the small intestine. In contrast to the duodenum, they are (intraperitonea/retroperitoneal?).
⦿ They are attached to the posterior abdominal wall by mesentery (a double layer of peritoneum).

Answer 31

Jejunum and Ileum
⦿ The jejunum and ileum are the distal two parts of the small intestine. In contrast to the duodenum, they are intraperitoneal.
⦿ They are attached to the posterior abdominal wall by mesentery (a double layer of peritoneum).

Question 32

Jejunum
• The jejunum is the midsection of the
small intestine, connecting the duodenum to the ileum. It is about —— m long, and contains the plicae circulares, and villi that increase its ——.
• Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
• The ————marks the division between the duodenum and the jejunum.

Answer 32

Jejunum
• The jejunum is the midsection of the
small intestine, connecting the duodenum to the ileum. It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area.
• Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
• The suspensory muscle of duodenum marks the division between the duodenum and the jejunum.

Question 33

Jejunum
⦿ The jejunum begins at the ——
flexure. There is no clear external
demarcation between the jejunum and ileum – although the two parts are macroscopically different. The ileum ends at the ——— junction.
⦿ At this junction, the ileum invaginates into the cecum to form the ——— valve.

Answer 33

Jejunum
⦿ The jejunum begins at the duodenojejunal
flexure. There is no clear external
demarcation between the jejunum and ileum – although the two parts are macroscopically different. The ileum ends at the ileocecal junction.
⦿ At this junction, the ileum invaginates into the cecum to form the ileocecal valve. Although it is not developed enough to control movement of material from the ileum to the cecum, it can prevent reflux of material back into the ileum

Question 34

Jejunum
⦿ Has long leaflike —-
⦿ Many ———
⦿ An intermediate number of goblet cells
The key to its identification is that although it has villi (part of the small intestine), it doesn’t contain ——— or —-/

Answer 34

Jejunum
⦿ Has long leaflike vilii
⦿ Many plicae circulares
⦿ An intermediate number of goblet cells
The key to its identification is that although it has villi (part of the small intestine), it doesn’t contain Brunner’s glands or Peyer’s patches.

Question 35

Jejunum starts at L—
Jejunum occupies the ——- quadrant
Ileum occupies the ———-quadrant

Answer 35

L3
Left upper quadrant
Right lower quadrant

Question 36

Ileum
The ileum: The final and longest section of the small intestine.
It is about —— m long, and contains fewer ——, which are short and broad-tipped (clublike) compared to the jejunum.
Relatively abundant —- cells
It absorbs mainly vitamin B—— and bile acids, as well as any other remaining nutrients.
Responsible for the final stages of protein and carbohydrate digestion
The ileum joins to the cecum of the large intestine at the ———- junction.

Answer 36

Ileum
The ileum: The final and longest section of the small intestine.
It is about 3 m long, and contains fewer villi, which are short and broad-tipped (clublike) compared to the jejunum.
Relatively abundant goblet cells
It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients.
Responsible for the final stages of protein and carbohydrate digestion
The ileum joins to the cecum of the large intestine at the ileocecal junction.

Question 37

8 DIFFERENCES B/W JEJUNUM & ILEUM

Answer 37

1. Walls.
   Jejunum : Thicker and more vascular.
   Ileum: Thinner and less vascular.
2. Location.
   Jejunum: Occupies upper and left parts of the intestinal area.
   Ileum: Occupies lower and right parts of the intestinal area.
3. Lumen.
   Jejunum: Wider and often empty.
   Ileum: Narrower and often loaded.
4. Mesentery.
   Jejunum: a) Windows present.
   (b) Fat less abundant.
   (c) Arterial arcades, 1 and 2.
   (d) Vasa recta longer and fewer.
   Ileum: (a) No windows.
   (b) Fat more abundant.
   (c) Arterial arcades, 3 and 6.
   (d) Vasa recta shorter and more numerous.
5. Circular mucosal folds
   Jejunum: Larger and more closely set.
   Ileum: Smaller and sparse.
6. Villi.
   Jejunum: Large, thick ( leaf-like) and more abundant.
   Ileum: Shorter, thinner (finger-like) and less abundant.
7. Peyer’s patches
   Jejunum: absent
   Ileum: present
8. Solitary lymphatic follicles.
   Jejunum: fewer
   Ileum: more numerous

Question 38

Vasculature and lymphatics
Duodenum
⦿ The arterial supply of the duodenum is derived from two sources:
⦿ Proximal to the major duodenal papilla – supplied by the ——- artery (branch of the ——-).
⦿ Distal to the major duodenal papilla – supplied by the ——- artery (branch of ———).
⦿ This transition is important – it marks the change from the embryological foregut to midgut. The veins of the duodenum follow the major arteries and drain into the ——— vein

Answer 38

⦿ Duodenum
⦿ The arterial supply of the duodenum is derived from two sources:
⦿ Proximal to the major duodenal papilla – supplied by the gastroduodenal artery (branch of the coeliac trunk).
⦿ Distal to the major duodenal papilla – supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery).
⦿ This transition is important – it marks the change from the embryological foregut to midgut. The veins of the duodenum follow the major arteries and drain into the hepatic portal vein

Question 39

Jejunum and ileum
The main arterial supply of the jejunum and the ileum is from a single artery known as the ———— and between —- to —— of its branches which form anastomoses loops known
as arterial —— with terminal ——- or —— branches.
It should be noted that a double row of arcades supplies the ——

Answer 39

Jejunum and ileum
The main arterial supply of the jejunum and the ileum is from a single artery known as the superior
mesenteric and between fifteen to eighteen of its branches which form anastomoses loops known
as arterial arcades with terminal vasa recta or straight branches.
It should be noted that a double row of arcades supplies the ileum

Question 40

Blood supply of the jejunum and ileum

Answer 40

Jejunum and Ileal branches of the SMA form arcade to join with vasa recta

Question 41

FUNCTION OF THE SMALL INTESTINE
• Food from the stomach is allowed into the duodenum through the pylorus by a muscle called the ——-.
• Digestion
• The small intestine is where most chemical digestion takes place.
• Many of the digestive enzymes that act in the small intestine are secreted by the —— and enter the small intestine via the ——— duct.
• Pancreatic enzymes and bile from the gallbladder enter the small intestine in response to the hormone ———, which is produced in the small intestine in response to the presence of nutrients.
• Secretin, another hormone produced in the small intestine, causes additional effects on the pancreas, where it promotes the release of ——- into the duodenum in order to neutralize the potentially harmful acid coming from the stomach

Answer 41

FUNCTION OF THE SMALL INTESTINE
• Food from the stomach is allowed into the duodenum through the pylorus by a muscle called the pyloric sphincter.
• Digestion
• The small intestine is where most chemical digestion takes place.
• Many of the digestive enzymes that act in the small intestine are secreted by the pancreas and enter the small intestine via the pancreatic duct.
• Pancreatic enzymes and bile from the gallbladder enter the small intestine in response to the hormone cholecystokinin, which is produced in the small intestine in response to the presence of nutrients.
• Secretin, another hormone produced in the small intestine, causes additional effects on the pancreas, where it promotes the release of bicarbonate into the duodenum in order to neutralize the potentially harmful acid coming from the stomach

Question 42

List 10 disorders of small intestine

Answer 42

Disorders
⦿ Colon cancer
⦿ Small bowel bacterial overgrowth syndrome
⦿ Paralytic ileus
⦿ Maropthisis
⦿ Crohn’s disease
⦿ Celiac disease
⦿ Carcinoid
⦿ Meckel’s Diverticulum
⦿ Gastric dumping syndrome
⦿ Infectious diseases
⦿ Mesenteric ischemia
⦿ Intussusception

Question 43

Boundaries of the epiploic foramen

Answer 43

Superiorly: caudate lobe
inferiorly: first part of the duodenum
Anterior: free margin of lesser omentum containing portal triad
Posteriorly:IVC

Question 44

Structures that root of mesentery crosses

Answer 44

2nd & 3rd part of duodenum
Aorta
IVC
Right ureter
Right psoas major muscle
Right Gonadal artery

Question 45

Root of mesentery extends from— to —

Answer 45

Duodenojejunal flexure(L2)
Ileocecal junction ( sacroiliac joint)