Liver, Gallbladder, Pancreas, Spleen

Question 1

describe the liver and its functions

Answer 1

LARGEST GLAND

functions:
-carb, protein, fat metabolism
-forms bile
-destroys old red blood cells
-vitamin and iron storage

Question 2

what does bile do?

Answer 2

mixes with chyme in stomach

needed for emulsification, absorption and digestion of fat and makes intestinal contents more alkaline

Question 3

what is contained within the lesser omentum?

Answer 3

portal structures

Question 4

what is the hepatic artery?

Answer 4

+ branches supply oxygenated blood to the liver = roughly 25% of liver’s blood supply

Question 5

what is the portal vein?

Answer 5

delivers blood drained from abdominal digestive organs to the liver

delivers roughly 75% of liver’s blood supply

Question 6

what is the bile duct?

Answer 6

delivers bile from liver (and gall bladder) to the duodenum

Question 7

what does the portal (=hepatic portal) vein collect blood from?

Answer 7

1) gastroduodenal vein
—> craniopancreatico-duodenal vein (L lobe of pancreas and duodenum)
—> right gastroepiploic vein (greater curvature of stomach)
2) splenic vein
—> left gastroepiploic vein (greater curvature of stomach)
—> pancreatics (R lobe of pancreas)

Question 8

name the 3 parts of the portal triad (flow of blood and bile within lobular liver)

Answer 8

1) portal areas (traids, tracts, fields)
2) hepatic sinusoids, bile canaliculi
3) centrilobular region

Question 9

describe the portal areas of the portal triad

Answer 9

regions containing microscopic branches of the portal vein, hepatic artery and bile ductule

bile ductule lined by cuboidal cholangiocytes

Question 10

describe the hepatic sinusoids/bile canaliculi of the portal triad

Answer 10

hepatocytes interact with venous and arterial blood in hepatic sinusoids

also secrete bile into bile canaliculi that transport bile to the bile ductules as part of the biliary system

canaliculi = channels formed by tight junctions between hepatocytes

Question 11

describe the centrilobular region of the portal triad

Answer 11

deoxygenated, processed blood is carried to the central vein which ultimately drains into the caudal vena cava

Question 12

how does the liver drain to caudal vena cava?

Answer 12

via hepatic veins

multiple hepatic veins drain blood from the liver –> anatomically very short

Question 13

describe the functions of the gall bladder

Answer 13

-bile storage (from liver)
-concentration –> removal of water from electrolytes
-duodenum/jejunum release cholecystokinin that causes gallbladder to rhythmically contract and causes sphincter of the hepatopancreatic ampulla to relax in order to release bile into duodenum

-bile emulsifies fat

Question 14

what does the sphincter of oddi do?

Answer 14

controls bile and pancreatic juice drainage

-prevents bile from entering duodenum and instead it flow up the cystic duct to gallbladder for concentration and storage

Question 15

describe the mucosa in the gallbladder

Answer 15

simple columnar epithelium with short microvilli

Na+ and water are transported into the lamina propria as part of bile concentration

Question 16

describe the muscularis externa in the gallbladder

Answer 16

multiple smooth muscle layers for peristalsis to empty bile from gallbladder

Question 17

describe adventitia/serosa in the gallbladder

Answer 17

dense CT adventitia anchors it to the liver –> free surface covered by serosa (peritoneum)

Question 18

how does bile flow in the equine liver

Answer 18

FLOWS CONTINUALLY BC NO GALLBLADDER

widened bile duct delivers bile to duodenum

Question 19

describe the pancreatic ducts and the pancreas type

Answer 19

pancreatic ducts form within the body of the pancreas and drains into the duodenum

–> smaller gland with 2 components: exocrine and endocrine

Question 20

describe the exocrine gland component of the pancreas

Answer 20

produces a digestive juice that is discharged into duodenum through ducts

juice contains enzymes that break down protein, carbs, and fats

Question 21

describe the endocrine gland component of the pancreas

Answer 21

cell clumps scattered between exocrine acini called pancreatic islets –> are the source of insulin, glucagon, and gastrin

critical for carb metabolism

Question 22

what is the left lobe of the pancreas adjacent to? the right lobe?

Answer 22

left: adjacent to great curvature
right: descending duodenum

Question 23

how do the exocrine secretions work in the pancreas?

Answer 23

secrete digestive enzymes from pancreatic acini

acinus –> intercalated duct –> intralobular duct

Question 24

how do the endocrine secretions work in the pancreas?

Answer 24

secrete hormones from islets of langerhans

release into capillaries

Question 25

what are acinar cells?

Answer 25

release granules of digestive enzymes

Question 26

what are centroacinar cells?

Answer 26

produce alkaline fluid to keep digestive enzymes inactive

Question 27

describe pancreatic acini

Answer 27

compound tubuloacinar serous glands 40-50 acinar cells per pancreatic acinus basal lamina separates acinar cells from septa 3-4 centroacinar cells of intercalated duct in lumen

Question 28

what is the function of islet of langerhans?

Answer 28

secrete hormones that regulate blood sugar and digestion into fenestrated capillaries

Question 29

describe islet of langerhans

Answer 29

1 islet may contain hundreds of cells 1 million islets per pancreas pale staining cells each islet is heavily vascularized

Question 30

describe alpha/A cells

Answer 30

20% of islet cells periphery of islet PRODUCES GLUCAGON

Question 31

describe beta/B cells

Answer 31

70% of islet cells center of islet PRODUCES INSULIN

Question 32

describe delta/D cells

Answer 32

5% of islet cells periphery of islet PRODUCES SOMATOSTATIN

Question 33

what 2 arteries anastomose along the pancreas and 1st part of duodenum

Answer 33

celiac and cranial mesenteric arteries

Question 34

describe the spleen and its functions

Answer 34

LARGEST LYMPHOID ORGAN functions: -store RBC's and platelets -destroy old RBC's -filters foreign particles, bacteria and phagocytic cells -produce lymphocytes

Question 35

where does the spleen originate?

Answer 35

dorsal mesogastrium

Question 36

describe the red pulp of the spleen

Answer 36

contains numerous macrophages in splenic cords and splenic sinuses that hemolyze damaged RBCs

Question 37

describe the white pulp of the spleen

Answer 37

contains about a quarter of the body's lymphocytes that attack antigens circulating in blood