Jejunum, Ileum and Large Intestines

Question 1

What is the longest part of the GI tract?

Answer 1

jejunum and ileum

Question 2

Describe the jejunum and ileum?

Answer 2

convoluted tube that runs from the duodenojejunal junction to the ileocecal valve

Question 3

What best describes the change from jejunum to ileum?

Answer 3

gradual - no clear boundary

Question 4

Where does the jejunum lie?

Answer 4

upper left abdomen

Question 5

Where does the ileum lie?

Answer 5

lower right abdomen and partly in the pelvis

Question 6

What is the ratio of jejunum to ileum?

Answer 6

40% jejunum - 60% ileum

Question 7

What do the jejunum and ileum had from and what are they suspended by?

Answer 7

posterior abdominal wall by the mesentery

Question 8

What structures does the small intestine cross?

Answer 8

• base crosses 3rd part of the duodenum
• aorta
• inferior vena cava
• right gonadal vessels
• right ureter

Question 9

What is contained within the mesentery?

Answer 9

• branches of the superior mesenteric artery, forming anastomatic arcades
• branches of the superior mesenteric vein
• lymph vessels
• nerves

Question 10

Describe the jejunum?

Answer 10

• wide
• more plica circulares
• no peyer’s patches
• MALT (mucous associated lymphoid tissue)

Question 11

Describe the ileum

Answer 11

• narrow
• fewer plic circulares
• numerous Peyer’s patches (aggregations of lymphoid tissue along the antimesenteric border)
• MALT

Question 12

What does the ilecocecal valve consist of?

Answer 12

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

Question 13

Where is the ileocecal valve situated?

Answer 13

at the junction of the small intestine and the large intestine (caecum)

Question 14

What is the function of the ileocecal valve?

Answer 14

limit the refluc of colonic contents into the ileum and possibly control the flow of ileal contents into the caecum

Question 15

What are jejunal and ileal arteries branches of?

Answer 15

superior mesenteric artery

Question 16

Where does the superior mesenteric artery arise from?

Answer 16

aorta at the lower border of L1

Question 17

What does the superior mesenteric artery supply?

Answer 17

Supplies the midgut (from ampulla of Vater in duodenum to 2/3 along the transverse colon)

Question 18

What does the superior mesenteric artery form within the mesentery?

Answer 18

series of vascular anastomotic arcades

Question 19

What has one pr two arcades with long vasa recta in the mesentery?

Answer 19

jejunum

Question 20

What has many arcades with short vasa recta in its mesentery?

Answer 20

ileum

Question 21

Where do jejunal and ileal veins drain into? And what does this eventually form?

Answer 21

superior mesenteric vein

portal vein

Question 22

Draw a diagram indicating the lymphatic drainage of the small intestine

Answer 22

Question 23

How is the mucous memrbane of the small intestine adapted to increase asbsoprtive SA?

Answer 23

raised in multiple villi (finger-like projections)

Question 24

What is the function of the lacteal at the centre of each villus?

Answer 24

absoption of digested fats and lipids (chyle)

Question 25

Where does chyle pass from and to?

Answer 25

* pass from lacteals into mesenteric lymph channels * don't pass through lymph nodes * coverge on cisterna chyli

Question 26

Where does cisterna chyli lie and where does it pass through?

Answer 26

* lies in upper abdomen * pass through diaphragm as the thoracic duct

Question 27

Draw a diagram showing the nerve supply of the small intestine

Answer 27

Question 28

Where is pained referred from the small intestine

Answer 28

periumbilical (T10)

Question 29

What are the functions of the large intestine?

Answer 29

* fluid-electrolyte balance - absorbs fluids and salts * Dries out the chyme to form faeces

Question 30

Where does the LI run between?

Answer 30

caecum to the rectum and anal canal

Question 31

How long is the LI?

Answer 31

approximately 1.5m long

Question 32

What are the components of the LI?

Answer 32

Caecum, ascending colon, hepatic (right colic) flexure, transverse colon, splenic (left colic) flexure, descending colon, sigmoid colon

Question 33

What parts of the LI are retroperitoneal?

Answer 33

ascending & descending colon

Question 34

What parts of the LI are on the mesentery? (intraperitoneal)

Answer 34

transverse & sigmoid colon

Question 35

How does the diameter of the LI compare with the SI?

Answer 35

larger unless contracted by a wave of peristalsis

Question 36

What do longitudnal smooth muscle fibres thicken to form?

Answer 36

3x taenia coli

Question 37

What length are taenia coli?

Answer 37

shorter than the LI

Question 38

What are the sacculations/pouches of the LI known as?

Answer 38

haustra mobile

Question 39

What is the name for the tags of fat in the LI?

Answer 39

Possesses epiploic/omental appendices (appendices epiploicae)

Question 40

What does the LI lack that is present in the SI?

Answer 40

Peyer's patches

Question 41

What is the widest and first part of the LE?

Answer 41

caecum

Question 42

Where is the caecum located?

Answer 42

Lies below the junction of the ileum with the large intestine in the right iliac fossa

Question 43

What is the caecum continous with?

Answer 43

Continuous with the ascending colon

Question 44

What is the caecum covered by?

Answer 44

Covered by peritoneum but not on a mesentery

Question 45

How does the ileum enter the caecum?

Answer 45

enters the caecum obliquely and partly invaginates into it, forming ileocaecal orifice

Question 46

What is the veriform appendix?

Answer 46

A blind intestinal diverticulum, from the posteromedial aspect of the caecum

Question 47

What cinverge of the root of the veriform appendix? And what is the name of this point?

Answer 47

The 3 taeniae coli converge at the root of the vermiform appendix Root of vermiform appendix is at McBurney’s point

Question 48

Describe the submucosa of the veriform appendix

Answer 48

packed full of lymphoid tissue

Question 49

Where is the veriform appendix suspended?

Answer 49

suspended on a short but highly variable mesoappendix that transmits the appendicular vessels

Question 50

What are the differnet anatomical positions the veriform appendix can be found in?

Answer 50

retrocaecal (65%); pelvic (30%); subcaecal; retroileal; pre- ileal

Question 51

Where does the base of the appendix most often lie deep to?

Answer 51

a point that is one third of the way along the oblique line joining the right anterior superior iliac spine to the umbilicus (McBurney point).

Question 52

Where is the ascending colon located?

Answer 52

in the right lumbar region

Question 53

What is the ascending colon between?

Answer 53

caecum and hepatic flexure

Question 54

Describe the attachment of the ascending colon

Answer 54

secondarily retroperitoneal

Question 55

Where is the right parabolic gutter formed?

Answer 55

between ascending colon and posterior abdominal wall

Question 56

Where does the transverse colon extend between?

Answer 56

hepatic and splenic flexures

Question 57

What is the transverse colon suspended by?

Answer 57

transverse mesocolon

Question 58

Describe the attachment of the transverse colon

Answer 58

intraperitoneal

Question 59

What is the hepatic (right colic) flexture related to?

Answer 59

liver

Question 60

What is the splenic (left colic) flexture related to?

Answer 60

spleen

Question 61

What is the transverse mesocolon?

Answer 61

mesentery of the ytransverse colon

Question 62

What does the root of the transverse mesoclon cross?inferior edge of the pancreas in the left lumbar region

Question 63

Where is the descending colon located?

Answer 63

left lumbar regiom, hidden anteriroly by the small intestine

Question 64

What forms the left paracolic gutter?

Answer 64

descending colon and posterior abdominal wall

Question 65

What is the sigmoid colon a continuation of?

Answer 65

Continuation of the descending colon in front of the pelvic inlet

Question 66

What is the sigmoid colon suspended by?

Answer 66

sigmoid mesocolon

Question 67

What is the sigmoid colon continous with?

Answer 67

Continuous with the rectum in front of the 3rd sacral vertebra

Question 68

Where is the rectum located within the peritoneum?

Answer 68

Retroperitoneal

Question 69

Where does the rectum begin?

Answer 69

in front of 3rd sacral vertebra

Question 70

What does rhe rectum follow the curve of?

Answer 70

sacrum and coccyx

Question 71

Where does the rectum end?

Answer 71

Ends in front of the tip of the coccyx by piercing the pelvic diaphragm & becoming continuous with the anal canal

Question 72

What does the rectum lack?

Answer 72

Lacks taenia, haustra or appendices epiploica

Question 73

What is the function of the rectum?

Answer 73

Stores faeces

Question 74

How long is the anal canal

Answer 74

approx. 4cm

Question 75

What is the anal canal

Answer 75

canal from pelvic diaphragm to the anus conduit to the outside world

Question 76

Where does the superior mesenteric artery originate

Answer 76

lower border of L1 vertebra

Question 77

What do branches of the superior mesenteric artery supply?

Answer 77

part of the large intestine, from vermiform appendix to proximal 2/3 of the transverse colon

Question 78

What are the 3 main branches of the superior mesenteric artery that form anastomoses in the LI

Answer 78

− Ileocolic artery: Caecum; appendicular artery − Right colic artery: Ascending colon − Middle colic artery: Transverse colon

Question 79

Describe the appendicular artery

Answer 79

a terminal artery that runs close and parallel to the appendi

Question 80

Where does the inferior mesenteric artery arise from?

Answer 80

arises from aorta at L3

Question 81

What do the branches of the inferior mesenteric artery supply?

Answer 81

supply distal 1/3 of the transverse colon, the splenic flexure, descending colon & sigmoid colon

Question 82

What are the branches of the inferior mesenteric artery and what do they supply?

Answer 82

− Left colic artery: Splenic flexure, descending colon − Sigmoid artery: Sigmoid colon

Question 83

What does the inferior mesenteric artery end as?

Answer 83

ends as the superior rectal artery supplying the rectum & anal canal

Question 84

What nerves run with the coeliac trunk to the foregut?

Answer 84

− Sym from T5-9 (greater splanchnic) − PSym from vagus

Question 85

What nerves run with the superior mesenteric artery to the midgut?

Answer 85

− Sym from T10-11 (lesser splanchnic) − PSym from vagus

Question 86

What nerves run with the inferior mesenteric artery to the hindgut?

Answer 86

− Sym. from T12-L3 (least splanchnic and lumbar splanchnic nerves) − Psym. from S2-4

Question 87

Where does pain from areas supplied by the coeliac trunk refer to?

Answer 87

epigastric region (T7-9)

Question 88

where does Pain from areas supplied by Superior mesenteric artery refer to?

Answer 88

Periumbilical region (T10-11) − Appendicitis pain in the first 6-8h

Question 89

Where does pain from areas supplied by the inferior mesenteric artery refer to?

Answer 89

suprapubic region (T12)