Anatomy 5 - Bleeding in the GI tract Flashcards

1
Q

what are the functions of the large intestine?

A

Defence (commensal bacteria)Absorption (H2O and electrolytes)Excretion

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2
Q

How is the caecum related to the peritoneum?

A

Intraperitoneal (quite mobile)

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3
Q

How is the ascending colon related to the peritoneum?

A

Secondarily retroperitoneal

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4
Q

What does secondarily retroperitoneal mean?

A

It originally was originally intraperitoneal (embryology)

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5
Q

What is the transverse colon in relation to the peritoneum?

A

intraperitoneal - highly mobile (has own mesentery)

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6
Q

Descending colon in relation to the peritoneum?

A

Secondarily retroperitoneal

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7
Q

What is the sigmoid colon in relation to the peritoneum?

A

Intraperiotneal - quite mobile as it has its own mesentery

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8
Q

Where are the 2 paracolic gutters?

A

Between the lateral edge of the ascending and descending colon and abdominal wall (called left and right paracolic gutters)

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9
Q

What are the paracolic gutters part of?

A

The greater sac of the peritoneal cavity

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10
Q

Where do the teniae coli run from and to?

A

From the caecum to the distal end of the sigmoid colon

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11
Q

What are the haustra?

A

Small pouches in the colon formed from the tonically contracted teniae coli

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12
Q

What causes darker blobs on a plain AXR?

A

Air

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13
Q

What does faeces appear like in the rectum on a plain AXR?

A

“Mottled” - mixture of air and faeces

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14
Q

In what part of the abdomen do the caecum and appendix lie?

A

The right iliac fossa

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15
Q

What is the opening of the ileum into the caecum called?

A

The ileocaecal orifice

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16
Q

What is the opening of the appendix into the caecum called?

A

Appendiceal orifice

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17
Q

How is the appendix most often located in comparison to the caecum?

A

Retrocaecal (64%)Position can vary causing a variation in the symptoms people present with e.g. men can present with testicular pain due to extending down to the pelvis and irritating structures

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18
Q

On what part of the caecum is the appendiceal orifice mostly always on?What does this correspond to?

A

The posteromedial wallMcBurney’s point (1/3 of the way between right Anterior Superior Iliac Spine and the umbilicus)Usually the point of maximum tenderness in appendicitis

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19
Q

In what part of the abdomen does the sigmoid colon lie?

A

left iliac fossa

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20
Q

What is the mesentery of the sigmoid colon called

A

Sigmoid mesocolon (gives it a considerable degree of movement)

21
Q

Volvolus?

A

Abnormal twisting of a part of the GI tract

22
Q

What is it called when the sigmoid colon twists around itself?What does this result in?What is the bowel at risk of if it is left untreated?

A

Sigmoid volvulusBowel obstructionInfarction

23
Q

Where does the abdominal aorta lie in relation to the IVC?

A

Left of the IVC

24
Q

What are the 3 midline branches of the abdominal aorta and what does each supply?

A

Celiac trunk (foregut organs)Superior mesenteric artery (midgut organs)Inferior mesenteric artery (hindgut organs)

25
Q

What do the lateral branches of the abdominal aorta supply? (3)

A

Body wall (posterolateral)Kidneys/ adrenal glandsGonads (ovaries/ testicles)

26
Q

What does the abdominal aorta bifurcate into?What does this further bifurcate into?

A

Common iliacsInternal and external iliacs

27
Q

See diagrams on superior mesenteric artery and inferior mesenteric artery

A

28
Q

What is the predominant artery which anastomoses between the branches of the SMA and IMA?

A

Marginal artery of Drummond

29
Q

What do arterial anastomoses between the SMA and IMA help to do?

A

Prevent intestinal ischaemia by providing a collateral route by which blood can travel

30
Q

Where does the hindgut extend to?

A

The proximal half of the nail canal (the pectinate line)

31
Q

What is the name of the line that divides the 2 half of the anal canal?

A

The pectinate line

32
Q

What is the remainder of the GI tract (from the pectinate line) supplied arterially by?

A

The internal iliac artery (middle and inferior rectal arteries branch from this) - there is a degree of anastomoses between these vessels

33
Q

What are oesophageal varies

A

Abnormal dilated veins with thin walls which therefore have the potential to rupture

34
Q

What often leads to the formation of varcies?

A

Pathology affecting the portal venous system

35
Q

What 2 vessels does the systemic venous system drain blood into?

A

Superior or inferior vena cava

36
Q

What does the inferior vena drain blood from in terms of the liver

A

Hepatic veins

37
Q

What are the 3 vessels that drain blood into the hepatic portal vein

A

Splenic vein (foregut)Superior mesenteric vein (midgut)Inferior mesenteric vein (hindgut)

38
Q

Are there any valves in the collateral veins of the portal systemic anastomoses

A

No - blood can flow either way

39
Q

Where are the 3 portal systemic anastomoses?

A

Skin around umbilicusDistal end of oesophagusRectum/ anal canal

40
Q

At the portal systemic anastomoses at the distal end of the oesophagus, where does the most inferior part and the most superior part drain

A

Superior = azygousInferior = hepatic portal veinAnastomoses form between these

41
Q

At the portal systemic anastomoses at the rectum/ anal canal, where does the most inferior part and the most superior part drain

A

Rectum and superior anal canal drains to inferior mesenteric veinMost inferior part of the GI tract drains to the internal iliac veinsAnastomoses form between these

42
Q

Portal-systemic anastomoses - skin around umbilicus?

A

normally the ligamentum teres remains closed throughout adult life and blood flows from the skin around the umbilicus via inferior epigastric veins to the IVC

43
Q

Where does the superior rectal vein branch from?

A

Inferior mesenteric vein

44
Q

Where does the middle rectal vein branch from?

A

The internal iliac vein

45
Q

Where does the inferior rectal vein branch from?

A

The internal iliac vein

46
Q

Name for increased blood pressure in the portal veins?What is this caused by?

A

Portal hypertensionLiver pathology e.g. cirrhosis

47
Q

What happens during portal hypertension to cause varicose?

A

Blood is 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 so dilate becoming varicose

48
Q

Clinical presentation of portal hypertension? (3)

A

Oesophageal varicesCaput medusaeRectal varcies