Foregut Anatomy of Canines and Equines

Question 1

what do the celiac artery branches supply?

Answer 1

organs derived from foregut + spleen

Question 2

what does the cranial mesenteric supply?

Answer 2

midgut

Question 3

what does the caudal mesenteric supply?

Answer 3

hindgut

Question 4

what 3 unpaired arteries supply the GI system?

Answer 4

celiac, cranial mesenteric, caudal mesenteric

Question 5

what are the 3 primary branches off the celiac?

Answer 5

splenic, hepatic, left gastric

Question 6

what does the splenic artery supply?

Answer 6

spleen, pancreas, stomach

Question 7

what does the hepatic artery supply?

Answer 7

liver, gallbladder, pancreas, duodenum

Question 8

what does the left gastric artery supply?

Answer 8

stomach, terminal end of esophagus

Question 9

what 2 structures pass through the esophageal hiatus?

Answer 9

esophagus
vagus nerve

Question 10

what do the major and minor splanchnic nerves do?

Answer 10

deliver preganglionic sympathetic axons from the abdomen to the celiac and cranial mesenteric ganglia where synapse will occur

Question 11

what do the vagal trunks do?

Answer 11

travel through the esophageal hiatus delivering preganglionic parasympathetic axons to the fore- and midgut

Question 12

what are periarterial plexuses?

Answer 12

when both postganglionic sympathetic and preganglionic parasympathetic axons are distributed to organs by traveling along with blood vessels

Question 13

describe the abdominal portion of the esophagus

Answer 13

once through the esophageal hiatus –> joins the cardia of the stomach

abdominal length of esophagus is very short before ending at the stomach

Question 14

what muscles make up the esophagus?

Answer 14

interwoven skeletal and smooth muscle tissue

–> closer to stomach = more smooth muscle

Question 15

what basic tissues and specialized cells are required for the esophagus transporting food?

Answer 15

stratified squamous epithelial cells for protection
mucous glands for lubrication
skeletal and smooth muscle

Question 16

describe the transitional anatomy of the esophagogastric junction

Answer 16

epithelium transitions from stratified squamous to simple columnar

has cardiac sphincter and gastric pits (deep invaginations in tissue)

Question 17

describe the specialization of the GI system in equines

Answer 17

hindgut specialists –> GI tract roughly 12x body length
elaborated cecum for fermentation
sacculated colon

Question 18

describe the specialization of the GI system in bovine

Answer 18

foregut specialists –> GI tract roughly 20x body length
elaborated stomach for fermentation
elongated ascending colon

Question 19

describe the position of the stomach using regional terminology

Answer 19

crosses 2 regions –> left hypochondriac region into xiphoid region

Question 20

describe the functions of the stomach

Answer 20

-acts as a food reservoir
-secretion of gastric juices –> released from gastric pits
-rhythmic segmentations begins the chemical breakdown of food
—> results in formation of chyme –> first part of digestion
-initiate protein digestion

Question 21

what do the gastric folds do?

Answer 21

aka rugae

increase lumen surface area and allow for stomach expansion

Question 22

describe the distinct regions of the stomach

Answer 22

cardia and pylorus –> mucous glands only

fundus and body –> secretion of gastric juice

Question 23

what does the in invagination of epithelium form?

Answer 23

dives downward at GASTRIC PITS to form GASTRIC GLANDS

Question 24

name the layers of the fundic gland from surface to deep level

Answer 24

1) simple columnar
2) mucous neck
3) parietal
4) chief

Question 25

describe the simple columnar layer of the fundic gland

Answer 25

secrete visible mucous –> gel like mucous that adheres to the stomach lining to prevent autodigestion

also modifies pH at cell membrane

Question 26

describe the mucous neck of the fundic gland

Answer 26

columnar with microvilli

produce soluble mucous that mixes/lubricates chyme –> reduces friction

Question 27

describe the parietal layer of the fundic gland

Answer 27

round/pyramidal with basally located nuclei

produce hydrochloric acid and gastric intrinsic factor

Question 28

describe the chief layer of the fundic gland

Answer 28

columnar, found at the base of the gland

produce and release pepsinogen, rennin, gastric lipase –> initiate protein digestion

Question 29

describe the difference between the gastric pits and the parietal cells on histology slide

Answer 29

parietal cells have the fried egg look

Question 30

describe the difference between active and resting parietal cells

Answer 30

more folds/elaboration of microvilli in active cells

resting = clear channel post secretion

Question 31

describe distinguishing traits of chief cells

Answer 31

-basal RER
-apical granules
-secreted into lumen
-pepsinogen –> pepsin

Question 32

describe the muscularis externa of the stomach

Answer 32

inner oblique, middle circular, outer longitudinal

function: innervated by the myenteric plexus

Question 33

describe the serosa of the stomach

Answer 33

thin CT layer
cuboidal mesothelium

function: secretes small amount of serous fluid into peritoneal cavity for lubrication

Question 34

describe the pyloric mucosa of the stomach

Answer 34

deeper gastric pits
branching, convoluted gastric glands

gastric glands are dominated by mucous secreting cells