lecture 7 Flashcards
(45 cards)
1
Q
Abdominal scarecrow:
A
- Abdominal aorta (starts at T12) = continuation of thoracic aorta
- Use the scarecrow – all single, unpaired structures supply the gut (2,3 and 6 not 9)
- All paired branches – supply abdominal wall and other structures
2
Q
Abdominal aorta aneurysms
A
- Localised enlargement of the abdominal aorta, where the diameter of the aorta at that particular level is more than 50% of its normal size
- Or the Diameter > 3cm
- Different types
- Back pain, pulsations in abdomen
- Associated with thoracic aorta and popliteal aneurysms
- Risk factors: Male, smoking, high blood pressure, family history
3
Q
A
4
Q
Celiac artery origin
A
arises from the aorta and passes below the median arcuate ligament
5
Q
Sup mesenteric artery origin
A
originates from the aorta between the celiac artery and renal arteries
6
Q
Inf mesenteric artery origin
A
comes off the anterolateral aspect of the left side of the aorta.
7
Q
Foregut contains
A
Lower part of oesophagus, stomach, 2/3rds duodenum
Liver, spleen, gallbladder, pancreas
8
Q
Foregut arteries:
A
Supplied by coeliac trunk; drained by splenic artery
9
Q
Note anastomosis around stomach:
A
Left and right gastric arteries and left and right gastroomental* arteries
10
Q
A
11
Q
Celiac trunk branches
A
left gastric artery
splenic artery
common hepatic artery
12
Q
- Left gastric artery
A
-Smallest branch
Its ascends across the diaphragm, giving rise to the oesophageal branches before continuing anteriorly along the lesser curvature of the stomach
It forms an anastomosis with the R gastric artery
13
Q
- Splenic artery
A
- Direct branch of celiac trunk
- Travels towards the spleen, behind the stomach
- On its course, it gives off →left gastroomental artery and short gastric arteries
- Supplies the larger curve of the stomach
14
Q
- Common hepatic artery
A
- Goes to general area of liver
→ Proper hepatic artery (only supplies liver) → cystic artery (gall bladder); left and right hepatic arteries
→ Right gastric artery (origin may vary) – supplies other part of the lesser curvature of the stomach
→ Gastroduodenal artery (part of stomach and duodenum)
→ Supradudenal artery
→ Right gastroomental artery (forms anist. With L on greater curve of stomach)
→ Superior pancreaticoduodenal artery (pancreas and duodenum)
15
Q
Midgut
A
- Midgut stretches from last 1/3rd of duodenum, jejenum, ileum, cecum & appendix, ascending colon, 1st 2/3rd of tv colon
16
Q
Midgut blood supply
A
Supplied by superior mesenteric artery; drained by superior mesenteric vein
17
Q
Superior mesenteric artery
(midgut)
A
- Jejenual and ileal branches (small intestine)
- Ileocolic artery → appendicular br (ilium and colon)
- Right colic artery (ascending colon)
- Middle colic artery (transverse colon)
18
Q
A
19
Q
Hindgut
A
- Last 1/3rd of tv colon, descending colon, sigmoid colon, rectum
20
Q
Hindgut blood supply
A
- Supplied by inferior mesenteric artery; drained by inferior mesenteric vein
21
Q
Inferior mesenteric artery
(hindgut)
A
- Left colic artery (descending colon and last 1/3rd of transverse colon also forms anist. With middle colic artery by means of the marginal artery )
- Sigmoidal branches (sigmoid colon)
- Superior rectal artery (rectum)
22
Q
A
23
Q
Anastomosis: Foregut - Midgut
A
- Pancreaticoduodenal artery surround and supply the head of the pancreas
1. Sup pancreaticoduodenal artery:
Comes from -> gastroduodenal artery -> Common hepatic artery -> Celiac trunk
2. Inf pancreaticoduodenal artery:
One of the first branches of the sup mesenteric artery
24
Q
Anastomosis: Midgut - Hindgut
A
- Between sup mesenteric artery and inf mesenteric artery
1. Middle colic artery -> Sup mesenteric artery
Supplies transverse colon
2. Left colic artery -> 1st branch of inf mesenteric artery
1+2 = marginal artery of drumette – forms anastomosis
25
Venous drainage
IVC: Caval system
Located in posterior abdominal wall, ant to vert column and to the R of the abdominal aorta
Formed by union of common iliac veins at L5
Ascends sup and pierces diaphragm at T8 (near central tendon)
Drains the limbs, abdominal wall and paired structures
26
IVC: caval system branches
* Common iliac veins – from lower limbs and gluteal region
* Lumbar veins – from posterior abdominal wall
* Renal veins – from kidneys, left adrenal gland and
left testis/ovary.
* Right testicular/ovarian vein from right testes or ovary
* Right suprarenal vein – drains the right adrenal gland
* Hepatic veins – drain the liver
Found in liver, and when IVC passes behind the liver, the hepatic veins drain directly into IVC
27
NOTE:
* Left testicular/ovarian vein drains into the left renal vein
* Left adrenal vein drains into left renal vein
* No tributaries from spleen, pancreas, gallbladder drain into portal system
28
Portal hepatic vein: Portal system
– Carries venous blood rich in nutrients from GIT – to liver for processing
- Portal vein = most Nb vein in portal system
- It is a point of conversion of other veins
– Formed by union of splenic vein (drains area supplied by the celiac trunk) and superior mesenteric vein
– Posterior to head of pancreas on L2
Tributaries:
* Inferior mesenteric vein
* Gastric veins
* Cystic veins
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Portocaval anastomosis
- Connections between veins of the portal system and veins of the caval system
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If there is a blockage of IVC below kidneys:
First collateral supply:
- Have blood flow back through the common iliac vein, into inferior epigastric vein (connected to superior epigastric vein which is a contributing branch of the internal thoracic vein which drains into brachiocephalic vein and then into SVC)
Second collateral supply:
- Between superficial epigastric vein which is connected to the thoracic vein which also drains into the brachiocephalic and SVC
Third route:
- Via the lumbar vein, they contribute to the formation of the ascending lumbar vein which then directly drains into the azygos vein which then drains into the SVC
34
Obstruction of the portal system – Portal hypertension
- Blood is redirected through the portocaval anastomoses (under lower pressure)
35
Lymphatics of the gut tends to
follow arteries and not veins (like usual)
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Innervation: Abdominal wall
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The abdominal and pelvic viscera receive their motor innervation from
from autonomics derived from both sympathetic and parasympathetic nervous systems
- Sensory nerves also originating from the same visceral structures also travel along these sympathetic and parasympathetic fibres
39
Why does pain from abdominal organs may be referred to as found away from the organ?
- The diffuse nature of the autonomic nervous system is responsible for the equally diffuse nature of the sensory innervation that travels along with them
40
Parasympathetic fibers supplied by:
- L and R vagus nerve
- Pelvic splanchnic nerve
41
Sympathetic fibers supplied by:
- Thoracic splanchnic nerve
- Lumbar splanchnic nerve
These nerves travel to 3 ganglia;
- Celiac ganglion – foregut
- Sup mesenteric ganglion – midgut
- Inf mesenteric ganglion – hindgut
42
Parietal peritoneum innervation
- receives the same somatic nerve supply as the region of the abdominal wall that it lines
- Pain from parietal peritoneum is well localized and severe
- Is sensitive to pressure, pain, cuts and temperature
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visceral peritoneum innervation
- Supplied by the viscera that it covers
- Pain is poorly localized
- Only sensitive to stretch and chemical stimulation = dull cramping or aching sensation
- Pain is thus referred to as dermatomes which are supplied by the same sensory ganglia and spinal chord segments as the fibers innervating the viscera
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Referred pain:
- Pain perceived at a location which is not the location of the painful stimulus
- Most viscera only innervated by autonomic nerves, thus visceral/referred pain is conducted via different afferent
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