1- bleeding in GI tract + anatomy of blood vessels in anatomy

Question 1

what organs are part of the foregut?

Answer 1

oesophagus to mid-duodenum, liver, gallbladder, spleen and 1/2 pancreas

Question 2

what organs are part of midgut?

Answer 2

mid duodenum to proximal 2/3 of transverse, 1/2 of pancreas

Question 3

what organs are part of hindgut?

Answer 3

distal 1/3 of transverse colon to 1/2 of anal canal

Question 4

what do all organs in each region (foregut, midgut and hindgut) have in common?

Answer 4

organs in each region share the same arterial supply, venous drainage, lymphatic drainage

Question 5

what is the main supply to abdominal region?

Answer 5

abdominal aorta - they’re branches give off to regions

Question 6

what are 3 main midline branches?

Answer 6

1. coeliac trunk
2. superior mesenteric artery
3. inferior mesenteric artery

*the mesenteric arteries pass through mesentery

Question 7

what branch of abdominal aorta supplies foregut organs?

Answer 7

coeliac trunk

Question 8

what branch of abdominal aorta supplies midgut organs?

Answer 8

superior mesenteric artery

Question 9

what branch of abdominal aorta supplies hindgut organs?

Answer 9

inferior mesenteric artery

Question 10

what do lateral branches of abdominal aorta supply?

Answer 10

• kidneys/adrenal glands
• Gonads (ovaries / testes)
• body wall (posterolateral)

Question 11

where does coeliac trunk arise from?

Answer 11

it’s retroperitoneal and arises around T12 vertebral level (does have some variation but usually around there) then supplies area around foregut (oesophagus to mid duodenum, liver, gallbladder, spleen and 1/2 of pancreas)

Question 12

what are branches of coeliac trunk?

Answer 12

trifurcates into 3 branches:
- Splenic artery
- Hepatic artery
- Left gastric artery

each of these give rise to further branches (gastroduodenal and superior pancreaticoduodenal)

Question 13

what does abdominal aorta bifurcate into?

Answer 13

common iliacs

Question 14

what is course of splenic artery?

Answer 14

has very curly, bumpy course →runs along superior border of pancreas

Question 15

what is location of spleen?

Answer 15

Intraperitoneal organ within left hypochondrium

has diaphragm posteriorly, stomach anteriorly, splenic flexure inferiorly, left kidney medially

Question 16

what is an attempt to protect spleen?

Answer 16

soft organs so ‘Protected’ by ribs 9-11 →however rib fracture could pierce the soft , delicate spleen = substantial internal bleeding

Question 17

what is function of spleen?

Answer 17

breaks down red blood cells and produces bilirubin (cover more later)

Question 18

can you palpate spleen?

Answer 18

• generally not palpable unless enlarged but anatomy point of view should know that spleen and liver are closely related of diaphragm so have to time with breathing
• breathing in = moves down = more space in thorax and negative pressure for air →means that abdominal organs moved down so you can try and feel them

Question 19

what is blood supply to stomach?

Answer 19

r+l gastric arteries run along lesser curve and anastomose together

r+l gastro-omental arteries runa long greater curve and anastomose together

Question 20

where is
a) right and left gastric arteries arise from
b) right and left gastro-omental arteries arise from?

Answer 20

a) right from hepatic and left from coeliac trunk
a) right from gastroduodenal (from hepatic) and left from splenic

Question 21

what gives blood supply to liver?

Answer 21

Hepatic artery→Branches into Right and Left hepatic arteries

= but that only accounts for 20-25% of blood received by liver, rest is from hepatic portal vein

Question 22

where does superior mesenteric artery arise from?

Answer 22

abdominal aorta at level of L1 = supplies midgut organs

Question 23

what are branches of superior mesenteric artery?

Answer 23

• inferior pancreaticoduodenal
• middle colic
• right colic
• ileocolic
• appendicular
• jejunal and ileal

Question 24

what are branches of inferior mesenteric artery?

Answer 24

• left colic
• sigmoid colic
• superior rectal

Question 25

what is significant anastomosis of superior and inferior mesenteric arteries?

Answer 25

= this anastomoses are predominantly one artery called the marginal artery of Drummond

→clinically important as blood can still get round if blocked by using the collateral supply

Question 26

what blood supplies rectum?

Answer 26

internal iliac supplies the last bit of GI tract after hingut

Question 27

what blood supply supplies the hindgut organs?

Answer 27

inferior mesenteric artery

Question 28

what is pectinate line?

Answer 28

theoretical line along half of anal canal

Question 29

what is hepatic portal system?

Answer 29

drains venous blood from absorptive parts of GI tract + associated organs to liver for “cleaning”

Question 30

where does inferior vena cava drain?

Answer 30

runs behind liver (retroperitoneal)

• drains cleaned blood from the hepatic veins into the right atrium

Question 31

what is systemic venous system?

Answer 31

drains venous blood from all other organs and tissues into superior or inferior vena cava

Question 32

what does hepatic portal vein drain?

Answer 32

drains blood from foregut, midgut and hindgut structures to the liver for first pass metabolism - forms once 2 join together

Question 33

what does splenic vein drain?

Answer 33

drains blood from foregut structures to hepatic portal vein

Question 34

what does superior mesenteric vein drain?

Answer 34

drains blood from midgut structures to hepatic portal vein (which drains to liver for 1st pass metabolism)

Question 35

what does inferior mesenteric vein drain?

Answer 35

drains blood from hindgut structures to splenic vein

Question 36

what are the 3 main sites of anastamoses betwen hepatic portal venous system and systemic venous system?

Answer 36

1. end of oesophagus (distal end) - superior part drains to systemic by azygous, inferior part drains into hepatic by left gastric (but lots of variation)
2. skin around umbillicus (belly button) - drain back into common iliacs + inferior epigastric veins and then IVC
3. rectum/anal canal - rectum and superior anal canal drain to inferior mesenteric vein, inferior part of GI drains into internal iliac veins

= at these sites, presence of small collaterals means blood can flow both ways either into systemic or hepatic venous systems (no valves)

Question 37

what is portal hypertension and what happens?

Answer 37

• clinical term given to increased blood pressure within the portal veins
• can occur as a result of liver pathology, e.g. cirrhosis
• In the event of portal hypertension, blood will be diverted through the collateral veins back to the systemic venous system
• These collateral veins consequently have a much larger volume of blood through them than they are used to become varicose

Question 38

a) what is rectul varices?
b) what are hemorrhoids

Answer 38

a) occurs because of portal hypertension

b) due to general increased pressure

*people often say interchangeably but not the same thing!