Abdominal Viscera and Abdominal Vessels

Question 1

What does the digestive system consist of?

What does the alimentary canal consist of?

Name the pathway through the alimentary canal

Answer 1

digestive tube (mouth, pharynx and alimentary canal) plus liver, pancreas and salivary glands

esophagus, stomach and intestine

esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum and anal canal)

Question 2

1) Define the general term mesentery
2) What parts of the alimentary canal do not have mesentery associated with it?
3) Discuss embryology of mesentery

Answer 2

1) double layer of (splanchnic mesoderm) connecting serous membrane going down to intestinal tract with vessels between
2) esophagus, cecum and anal canal
3) as body forms tube and splanchnic mesoderm and endoderm come together to form a gut, they also form mesentery (splanchnopleure), making contact with gut

complete mesentery dorsally (fore/hind gut), none ventrally in midgut (yolk sac)

Question 3

Name the mesentery of the alimentary canal and their associated structures

Answer 3

1) Lesser omentum - comes from ventral mesogastrium

attached between lesser curvature of the stomach and the liver and covers the papillary process

2) Greater Omentum - comes from dorsal mesogastrium

drapers over entire GI but not attached; folds over on itself so there is a superficial and deep layer with an omental bursa in between

3) Mesoduodenum - attaches to the duodenum (where pancreas is located and celiac arterial branches
4) THE mesentery - made up of mesojejunum (jejunum) and mesoileum (ileum)
5) Mesocolon - attaches to colon and is where branches of cranial and caudal mesenteric arteries are located
6) Mesorectum - rectum, in pelvic cavity

Question 4

What regions of the body is the esophagus located?

Answer 4

cervical, thoracic, abdominal regions (all striated in dog, proximal 2/3 striated in cat)

Question 5

What are the sphincters of the stomach?

What are the regions of the stomach?

Answer 5

cardiac (at cardia) and pyloric (at pylorus)

1) cardiac (surround cardia)
2) fundic (fundus = blind end)
3) body
4) pyloric (antrum - triangular fold and canal which is guarded by sphincter)
5) Lesser curvature - cranial side near liver

Greater curvature - caudal side near intestines

Question 6

1) What are the three regions of the small intestine?
2) What are the parts of the duodenum?
3) Name some features of the last region?

Answer 6

1) duodenum, jejunum (middle - longest) and ileum (end - smallest)
2a) cranial flexure (curve right off beginning)
b) descending duodenum (first tract)
c) caudal flexure ( bottom curve)
d) ascending duodenum (second tract of duodenum)
e) duodenal-jejunal flexure - curve - transition btw duodenum and jejunum
3) antimesenteric vessel - vessel on side opposite of mesentery

ileocecal fold - mesentery that binds ileum and cecum

ileal (ileocolic) orifice - opening into cecum

Question 7

1) What are the regions of the large intestine?
2) What are some features of cecum?
3) What are the parts of the colon?
4) What are some features of the anal canal (wall of peritoneum)?

Answer 7

1) cecum, colon, rectum and anal canal
2) cecum is a blind sac, no appendix

cecocolic orifice - opening into colon

ileocecal fold - same as in ileum

3a) ascending colon (1st tract)
b) right colic flexure (first curve)
c) transverse colon (middle section)
d) left colic flexure (2nd curve)
3) descending colon (last tract leading to rectum)
4) in the retroperitoneal

anus = external opening

anal sacs = outpocketing

2 sphincters - internal anal sphincter (smooth m) and external anal sphincter (striated m)

Question 8

1) What are the functions of the liver?
2) What is the round ligament?
3) Name the different lobes
4) Where is bile stored and where does it empty?
5) Name the pathway of ducts from liver/gall bladder to pancreas

Answer 8

1) secretes bile salts which emulsify fat; develops in ventral mesogastrium
2) connects liver to diaphragm
3) right lateral lobe, right medial lobe –gallbladder–quadrate lobe, left medial lobe, left lateral lobe, caudate lobe (papillary process that pokes out and caudate process which pushes against kidney)
4) in the gallbladder, empties into duodenum
5) bile empties into cystic duct from gallbladder which joins with the hepatic duct (ducts from liver) to form the bile duct

Question 9

What two structures are found in the beginning of the duodenum and their function?

Answer 9

major and minor duodenal papillae, where the bile and pancreatic duct empty into small intestine

Question 11

1) What are the functions of the pancreas?
2) What’s its structure?
3) What are the ducts and where do they empty?

Answer 11

1) secretes proteolytic enzymes in duodenum, also endocrine secretions (insulin)
2) left lobe (greater omentum near stomach), body and right lobe (mesoduodenum near duodenum
3) pancreatic duct (smaller) empties with bile duct into major duodenal papilla

accessory pancreatic duct (larger) empties into minor duodenal papilla

Question 12

1) What are the functions of the kidney?
2) Discuss features of kidney
3) What does the medial border contain?

Answer 12

1) removes waste products from blood (urine), regulates fluid/salt balance (blood osmotic pressure)
2) right kidney is more cranial

right kidney is cupped by liver

left kidney is more loosely attached

feline kidneys are positioned more caudally

3) hilus where vessels and ureter enter –> lead to renal sinus where renal pelvis is located

Question 13

What are the structures of the kidney?

Answer 13

1) fibrous capsule surrounds kidney
2) renal cortex - outer superficial tissue that contains vascular glomeruli
3) renal medulla - deep tissue (outer and inner) next to cortex
4) renal pyramid - medulla sectioned into these shaeps between interlobar vessels
5) renal papilla - free tip of renal pyramid (not present as such in carnivores)
6) renal crest - median ridge produced by fusion of renal medula and renal pelvis

***during development, distinct lobation is present; lobes fuse to a lesser or greater extent –> carnivore kidneys appear unilobar

Question 14

What does the ureter do?

what are features of ureter?

Answer 14

conveys urine from kidney to urinary bladder

renal pelvis - expanded proximal end of ureter

pelvic recess - lateral expansion of renal pelvis btw interlobal vessels

Question 15

What does the spleen develop from?

What is its function?

Answer 15

dorsal mesogastrium

reservoir for blood cells, filters particles from blood, recycles over-aged erythrocytes

Question 16

What are the different branches of the aorta in the abdominal region?

Answer 16

branches to abdominal wall

branches to paired organs

branches to unpaired organs (GI and spleen)

terminal branches of aorta (within pelvic cavity)

Question 17

What are the branches of the abdominal wall and what do they supply?

Answer 17

1) lumbar aortic arteries - supply vertebral column, spinal cord, epaxial m. and skin over back
2) common trunk - supplies abdominal wall and adrenal gland via cranial abdominal artery and diaphragm
3) deep circumflex iliac aortic arteries - supply abdominal wall (caudally)

Question 18

Name the branches to paired organs and what they supply

What accompanies first two aortic branches of abdominal region?

Answer 18

1) renal artery - supplies kidney
2) ovarian or testicular artery - supplies gonad

satellite veins named the same as arteries –> empty into caudal vena cava

Question 19

Name the branches to unpaired organs and associated organs

What is the setup of all these arteries?

Answer 19

1) celiac artery - supplies cranial abdominal viscera (esophagus, stomach, duodenum, liver, gall bladder, pancreas and spleen)
- three branches = hepatic, left gastric and splenic arteries
2) cranial mesenteric artery - supplies duodenum to descending colon and also the pancreas
- branches = common trunk (middle and right colic, ileocolic arteries), caudal pancreaticoduodenal, and jejunal arteries
3) caudal mesenteric artery - supplies descending colon and rectum
- two branches = cranial rectal and left colic artery

***all connected in loops

Question 20

Name the terminal branches of the aorta and their associated organs

Answer 20

1) external iliac artery - paired - pelvic limbs
2) internal iliac artery - paired - pelvis wall and viscera
3) median sacral artery - unpaired - becomes median caudal artery of the tail

Question 21

1) What is the portal vein?
2) What two veins form the portal vein?
3) what veins branch off?
4) whats the circulation sequence?

Answer 21

1) conveys blood between two capillary beds (btw alimentary tract capillaries and liver sinusoids)
- satellite veins which drain the digestive tract empty into portal vein rather than caudal vena cava
2) caudal and cranial mesenteric veins
3) splenic and gastroduodenal vein join before entering liver
4) celiac and cranial and caudal mesenteric arteries and atheir branches –> alimentary, etc capillaries –> satellite veins –> portal vein –> hepatic sinusoids –> hepatic veins –> caudal vena cava

Question 22

what are portosystemic shunt

Answer 22

developmental defect in portal vein where blood bypasses liver and goes directly to caudal vena cava –> can show neuro signs

Question 23

What do the mesenteric lymph ducts form?

what is chyle?

Answer 23

lymp “lake” (cysterna chyla)

lymph that has a milky appearance because it contains ingested fat