anatomy of small and large intestines

Question 1

where does the jejunum begin

Answer 1

duodenojejunal flexure

Question 2

where does the ileum end

Answer 2

ileo ceacal junction

Question 3

how is digestion aided in the small intestine

Answer 3

addition of large amounts of fluid to the chyme

Question 4

where is the jejunum

Answer 4

upper left abdomen

Question 5

where is the ileum

Answer 5

lower right abdomen and pelvis

Question 6

how can you tell the difference between the jejunem and the ileum

Answer 6

gradual change

The jejunum is wider bored,
thicker walled, and redder than the ileum; its wall feels thicker (shirt sleeve through jacket sleeve) because the permanent infoldings of the submucosa, the plicae circulares,
are larger, more numerous, and more closely set in the jejunum, whereas in the upper part
of the ileum they are smaller and more widely separated and in the lower part they are absent

jejunum has fewer arcades with long and infrequent vasa recta

Question 7

where is the jejunal mesentery attached

Answer 7

post abdominal wall above and to the left of the aorta at L2

fat is deposited near the root and is scanty near the intestinal wall

Question 8

where is the ileal mesentery attached

Answer 8

Attached below and to the right of the aorta at
the SI joint

fat is deposited through out

Question 9

what is the name of the lymphoid tissue found in the mucous membrane of the lower ileum

Answer 9

Peyer’s patches

Question 10

what does the ileocaecal valve consist of

Answer 10

two horizontal folds of mucous
membrane that project around
the orifice of the ileum

it stops colonic contents leaking back into the ileum

Question 11

where do jejunal and ileal arteries branch from

Answer 11

superior mesenteric artery and its ileocolic branch

Question 12

where does venous blood from the small intestine drain to

Answer 12

superior mesenteric

vein, which forms the portal vein

Question 13

where is lymph drainage from the small intestine to

Answer 13

superior mesenteric
nodes, which are situated around the origin
of the SMA

Question 14

what is the innervation of the small intestine

Answer 14

sympathetic, lesser splanchnic nerve T10
and 11, and parasympathetic (vagus) nerves
via the superior mesenteric plexus

referred pain is peri-umbilical

Question 15

what is the origin of the SMA

Answer 15

arises from the aorta at L1 and
carries nerves (sympathetic) derived from T10 and 11. It supplies the midgut

Question 16

where are the lacteals

Answer 16

in the centre of each vilus for the absorption of fats and lipids (chyle)

Question 17

where does the chyle from the lacteals go

Answer 17

cisterna chyli in the upper abdomen . first goes to mesenteric lymph channels that do not pass through lymph nodes but converge on the cisterna chyli

Question 18

where does lymph from the nodes on the SMA pass to

Answer 18

cysterna chyli

Question 19

what is meckel’s diverticulum

Answer 19

a remnant of the vitello-intestinal duct and may ulcerate

2 inches long,
2 feet from the end of the ileum, in
2% of people

it may ulcerate, create a fistula or a cyst
symptoms may be similar to appendicitis

Question 20

how long is the colon

Answer 20

1.5 metres long

Question 21

what are the internal differences between the small and large intestine

Answer 21

large intestine:
Lacks plicae circularis
Lacks villi
Lacks peyers patches

large intestine is larger in diameter, has omental appendages, 3 taenia coli and haustra

Question 22

where is the caecum

Answer 22

right iliac fossa

may form recesses adjacent to it

the 3 taeniae coli converge here
covered by peritoneum but does not have a mesentery

Question 23

where is the appendix

Answer 23

Mc burneys point

1/3 up from ASIS to umbilicus

can be found in many different positions: pelvic; subcaecal;
retrocaecal; retro-ileal; pre-ileal

Question 24

describe the features of the appendix

Answer 24

a narrow blind ended tube hanging from the caecum
Its submucosa is packed full of lymphoid tissue
It is suspended on a short, but highly variable meso-appendix that transmits
the appendicular vessels

Question 25

where does the appendicular artery arise from

Answer 25

the ileocolic branch of the
superior mesenteric, from the aorta
at L1 with nerves derived from
T10/11

Question 26

describe the pain of appendicitis

Answer 26

refers pain to the peri umbilical region; the pain moves to right inguinal region later

Question 27

describe the blood supply to the caecum

Answer 27

Anterior caecal artery
Posterior caecal artery
Appendicular artery (from posterior
caecal)

Lymph drainage is to nodes on the
SMA

Question 28

where is the ascending colon

Answer 28

right lumbar region and is retroperitoneal. it is 13 cm long

Question 29

how long is the transverse colon

Answer 29

38 cms long, across the umbilical region

intra peritoneal

Question 30

where is the descending colon

Answer 30

left lumbar region
25 cms long
retroperitoneal

Question 31

where is the sigmoid colon

Answer 31

25-38 cms long
in front of the pelivc brim

it becomes continuous with
the rectum in front of the 3rd sacral vertebra
intraperitoneal

Question 32

where is the root of the transverse mesocolon

Answer 32

lies across the lower part of the pancreas

Question 33

what is sigmoid volvulus

Answer 33

It may rotate upon itself

Question 34

what is the ascending colon related to

Answer 34

the right kidney and duodenum with the ureter and major vessels medially

Question 35

what is the descending colon related to

Answer 35

the left kidney with the duodeno-jejunal

flexure, ureter and major vessels medially

Question 36

what are the branches of the SMA

Answer 36

Inferior pancreaticoduodenal 
intestinal arteries 
 ileocolic,
 right colic and
middle colic

Question 37

what are the branches of the IMA

Answer 37

left colic
sigmoid branches
ends as the superior rectal artery

Question 38

what structures are supplied by the IMA

Answer 38

1/3 of the transverse
colon, the splenic flexure, descending
colon and sigmoid colon
- hindgut

Question 39

what structures are supplied by the SMA

Answer 39

inferior duodenum, small intestine
head of pancreas
caecum,
ascending colon, hepatic flexure and
2/3 of the transverse colon

Question 40

what does the IMA end as

Answer 40

uperior rectal
artery supplying the rectum and anal
canal

Question 41

what does the IMA arise from

Answer 41

the aorta at L3 and carries sympathetic nerves derived from T12 (least splanchnic nerves) and parasympathetics from S 2, 3, 4 (NOT vagus)

Question 42

how does SMA and IMA anastomose

Answer 42

the Marginal Artery
(of Drummond)

which may form a collateral
circulation should the IMA
become obstructed

Question 43

what segments are associated with the coeliac trunk

Answer 43

(T7 – 9)

Question 44

what segments are associated with the Superior mesenteric

Answer 44

T10/11

Question 45

what segments are associated with the Inferior mesenteric

Answer 45

T12

Question 46

what is the marginal artery of Drummond

Answer 46

an anastomosis with the SMA and IMA

this forms a collateral circulation should the IMA become obstructed

Question 47

what are the branches of IMA

Answer 47

left colic artery supplies descending colon
sigmoid branches
superior rectal artery effectively the terminal branch of the IMA
arcades which supply the colon

Question 48

where is Auerbach’s myenteric plexus of ganglia and nerves

Answer 48

lies between the muscular layers to control peristalsis

inner circular and outer longitudinal layer

Question 49

what is Hirchsprung’s disease

Answer 49

Lack of normal development of the colonic innervation leads to a constricted, aganglionic segment of bowel, with a distended segment proximally (the innervation of which is normal)

Question 50

where is the ileocaecal junction

Answer 50

right iliac fossa

Question 51

what is the midgut

Answer 51

from the ampulla of Vater to 2/3rds along the transverse colon

Question 52

how long is the rectum

Answer 52

13 cm long
begins infront of the 3rd sacral vertebra
retroperitoneal

Question 53

where is the anal canal

Answer 53

rectal ampulla to anus

4 cm long

Question 54

what does the inferior pancreaticoduodenal artery supply

Answer 54

head of the pancreas and the ascending and inferior parts of the duodenum