Histology - Liver, Pancreas and Gall Bladder

Question 1

liver and pancreas development

Answer 1

outgrowth of the gut

Question 2

parenchyma of the liver and pancreas

Answer 2

composed of glandular epithelial cells

Question 3

parenchyma

Answer 3

the functional tissue of an organ as distinguished from the connective and supporting tissue

Question 4

functions of the liver

Answer 4

most diverse tissue in the body

Question 5

liver capsule

Answer 5

covered by collagenous connective tissue capsule

that is covered by a layer of mesothelial cells (simple squamous epithelium) derived from the peritoneum

Question 6

liver structure

Answer 6

made up of segments called lobules

hexagonal
branch of the hepatic vein called the centrolobular vein (central vein) at its centre and portal triads at each corner

Question 7

portal triads

Answer 7

branches of the vessels which enter at the aorta hepatic (hepatic vein and the hepatic artery)

include a third ‘tube’ - a branch of the conduit which leaves the liver at the aorta hepatic, the bile duct

Question 8

portal tracts include branches of….

Answer 8

hepatic portal vein

hepatic artery

bile ductule - lined by simple cuboidal ells called cholangiocytes

include lymphatic vessels

Question 9

hepatocytes

Answer 9

main cells of the liver

polyhedral epithelial cells form plates or sheets of cells with spaces in between form blood to flow through

blood channels = sinusoids

Question 10

sinusoids

Answer 10

lined by endothelial cells

narrow space between these lining cells and the hepatocytes - space of Disse (perisinusoidal space)
microvilli of the hepatocytes project into the space

endothelial = fenestrated
liquid component of the blood generally has free access to the hepatocytes

Question 11

connective tissue of the liver

Answer 11

portal tracts are accompanied by collagenous connective tissue

parenchyma of the liver is also supported by reticular fibres along with some Type 1 collagen that is found in the space of Disse

Question 12

connective tissue of the liver

Answer 12

hepatic stellate cells are found scattered in the space of Disse

modified fibroblasts and make connective tissue

store vitamin A within fat droplets in their cytoplasm

PATHOLOGICAL CONDITIONS
transform into myofibroblasts and produce scar tissue in the liver

Question 13

macrophages of sinusoids - KUPFFER CELLS

Answer 13

scattered within the sinusoids

remove particulate matter from the blood and help remove worn out red blood cells

Question 14

bile

Answer 14

alkaline solution containing water, ions, phospholipids, bilirubin and bile salts

Question 15

bilirubin

Answer 15

pigment which results from the breakdown of haemoglobin in the spleen

excreted in the bile - brown colour feces

Question 16

bile salts

Answer 16

necessary for the emulsification of its in the digestive tract

Question 17

primary bile that is produced by the hepatocytes

Answer 17

modified in several ways by cholangiocytes, the cells that line the biliary tree

Question 18

bile production

Answer 18

all hepatocytes produce bile

bile flows via bile canaliculi towards the bile ducts in the portal tracts and thence to the hepatic ducts

Question 19

bile canaliculi

Answer 19

small channels

formed by tight junctions in the cell membranes of adjacent hepatocytes

Question 20

gall bladder

Answer 20

muscular sac

Question 21

gall bladder - structure

Answer 21

lined by simple columnar epithelium backed by a lamina propriety of loose connective tissue rich in blood vesslels and lymphatic vessels, a coat of smooth muscle and an outer collagenous layer of adventitia

Question 22

gall bladder - function

Answer 22

stores bile

has a folded mucosa when empty - this flattened when distended

modifies the bile stored within it

Question 23

removal of bile by the gall bladder

Answer 23

actively pumping Na and Cl ions from the bile into the spaces between adjacent epithelial cells

water then follows de to the increase in osmotic pressure in these spaces, which become distended with fluid when the gall bladder is actively concentrating bile

water is carried away, largely by the lymphatic vessels of the lamina propria

Question 24

stimulation of the gall bladder

Answer 24

to contract and deliver bile to the duodenum

under nervous control and hormonal

Question 25

hormonal control of the gall bladder

Answer 25

hormone = cholecystokinin by endocrine cells of the duodenum when fatty food enter it

Question 26

gall bladder lining

Answer 26

tall columnar epithelial cells with a brush border

Question 27

gall bladder PATHOLOGY

Answer 27

cholecystitis

inflammation of the gall bladder

Question 28

pancreas

Answer 28

unusual - both an exocrine and endocrine gland

Question 29

exocrine pancreas

Answer 29

produces a litre of digestive juices containing..
proteases to break down proteins
lipase to break down lipids
nucleases to breakdown DNA/RNA
amylase to breakdown starch

enter the duodenum via the pancreatic duct

Question 30

endocrine pancreas

Answer 30

consists of small scattered islands of tissue called islets of Langerhans

produce a number of hormones including insulin and glucagon

Question 31

exocrine pancreas - activation of enzymes

Answer 31

enzyme produced as inactive proenzymes

pancreatic secretion arrives in the duodenum - enteropeptidase converts the inactive proteolytic enzyme trypsinogen to the active trypsin

begins a cascade that results in the activation of other enzymes

Question 32

exocrine pancreas - histology

Answer 32

thin connective tissue capsule that is continuous with connective tissue septa that divid the gland into lobules

Question 33

centroacinar cells - duct cells within the acini

Answer 33

smallest ducts in pancreas = intercalated ducts

extend into the acinus

nuclei and cytoplasm do not stain as intensely as the secretory cells

Question 34

bile and pancreatic ducts

Answer 34

join the common bile duct and opens inot the duodenum on a papillae: the hepatopancreatic ampulla