w19 liver/gallbladder physiology

name the two surfaces of the liver

diaphragmatic, visceral

describe the relational anatomy of the liver

inferior to the diaphragm, left lobe is anterior to stomach, right lobe is anterior to right kidney + superior to duodenum + pancreas + gallbladder

what two liver lobes are found on the anterior surface

right and left

what structure separates the right and left lobes of the liver

falciform ligament

what liver lobes are found on the posterior surface of the liver

caudate, quadrate

where is the caudate lobe located

inferior to IVC, between the left and right lobes

where is the quadrate lobe located

adjacent to the gallbladder

T or F: the visceral surface of the liver is irregular

true

role of the falciform ligament

divides left and right liver lobes, attaches liver to anterior abdominal wall

role of the hepatogastric ligament

connects liver to the stomach

role of the hepatoduodenal ligament

connects liver to duodenum

role of coronary/triangular ligaments

connects liver to diaphragm

T or F: there is no peritoneum between the liver and the diaphragm = bare area

true

what two vessels are involved in liver blood supply

hepatic artery + portal vein

role of hepatic artery

delivers oxygenated blood to the liver

role of the hepatic portal vein

delivers nutrient rich, deoxygenated blood

what is another term for the hilum

porta hepatis

which structures enter/exit the liver at the hilum (3)

hepatic portal vein, hepatic artery proper, common hepatic duct

the hepatic portal vein, hepatic artery proper, and the common hepatic duct all enter/exit the liver at the hilum. what are these three vessels called

portal triad

which structures make up the portal triad

hepatic portal vein, hepatic artery proper, common hepatic duct

role of the portal system

drains blood from the spleen, pancreas, gallbladder, and GI tract

what is the hepatic portal vein formed by

splenic vein, superior mesenteric vein

role of the biliary tract/tree

drains bile from the liver and gallbladder

what is the common bile duct formed by

common hepatic duct, cystic duct

what does the common bile duct join with

main pancreatic duct

what does the common bile duct + main pancreatic duct form

hepatopancreatic ampulla (of Vater)

role of the hepatopancreatic ampulla

storage for bile and pancreatic secretions

how are hepatocytes arranged

hexagonal units (hepatic lobules)

what two structures comprise the network of vessels carrying bile within the liver

bile canaliculi, bile ducts

describe what makes up a liver lobule

hepatocytes, bile ducts, and blood vessels are organized into structural and functional units

within lobules, describe how the hepatocytes are organized

into plates that are 1-2 cells thick

in lobules, hepatocytes are organized into plates that are 1-2 cells this. what are these called

hepatic laminae

what structure separates hepatic laminae within lobules

hepatic sinusoids

what are hepatic sinusoids (structurally)

highly permeable capillaries with intercellular clefts and fenestrations

role of hepatic sinusoids

allow hepatocytes to absorb substances from blood + release substances into the blood

in regards to liver lobules, where are portal triads located

one located in each corner of a lobule

T or F: each portal triad contains a branch of the hepatic artery, a branch of the hepatic portal vein, and a bile duct

true

what happens to blood from the portal triad (where does it flow to)

goes to hepatic sinusoids and then drains into a central vein

where is the central vein located

at the center of the hepatic lobule

what happens to all the central veins as they exit their lobules

they merge to form hepatic veins

central veins merge into hepatic veins once they leave the lobules. name these

left, middle, right

central veins merge into hepatic veins once they leave the lobules. where does the hepatic vein lead

IVC

role of Kupffer cells

engulf pathogens, debris, or old damaged blood cells

where are kupffer cells located

sinusoids

another name for kupffer cells

reticuloendothelial cells

which cells produce bile

hepatocytes

T or F: bile flows in the same direction as blood

false; opposite direction

list the path of bile, starting from hepatocytes and ending at the portal trias

hepatocytes produce it, it flows through bile canaliculi, then to the bile ducts of the portal triad

role of right and left hepatic ducts

collect bile from all bile ducts of each lobule, and then they unite to exit the liver as the common hepatic duct

what structure does the common hepatic duct join with, and what is the result

joins with cystic duct (gallbladder) = common bile duct

T or F: the common bile duct travels with the lesser omentum to the descending part of the duodenum

true

roles of the liver (5)

assess nutrient content of blood, synthesize plasma proteins, storage of vitamins and minerals, detoxifies and processes drugs/hormones, produces and secretes bile

what processes occur once we have high blood glucose (2)

glycogenesis, lipogenesis

what is glycogenesis

glucose converted to glycogen for storage

what is lipogenesis

glucose converted to FAs + triglycerides

what processes occur once we have low blood glucose (2)

glycogenolysis, gluconeogenesis

what is glycogenolysis

breakdown of glycogen to release glucose

what is gluconeogenesis

synthesis of new glucose from amino acids, lactate, and glycerol

when we’re fed, describe what happens to our FFAs

they’re bound to albumin proteins for transport in the blood, then converted to triglycerides and cholesterol for storage

when we’re fed, FFAs are converted to triglycerides and cholesterol. what happens to these

they’re converted to lipoproteins, and cholesterol is used to make bile

T or F: cholesterol is only used to make bile after we’re fed

false; continuously made

when we’re fasting, describe what happens to our FFAs

undergo beta-oxidation to produce ATP

when we’re fasting, what alternative energy source arises

ketone bodies

when we’re fed, what happens to our amino acids

plasma protein synthesis + structural protein cytoskeleton

when we’re fed, amino acids are used to make plasma proteins. list these (7)

albumin, globulin, prothrombin, fibrinogen, transferrin, ferritin, lipoproteins

when we’re fasting, what happens to our amino acids

broken down and used to make ATP and glucose

what vitamins does the liver store

fat soluble: A D E K B12

iron is stored in the liver until required for which process

erythropoiesis

what does the liver convert alcohol into

acetaldehyde

what does the liver do to hormones and drugs

makes them water soluble so the kidneys can excrete them

list 3 steroid hormones that the liver converts into water soluble substances

aldosterone, cortisol, estrogen

what does the liver do to bilirubin

excretes it into bile

role of the gallbladder

stores and concentrates bile

storage capacity of the gallbladder

30-60 ml

in regards to the liver, where is the gallbladder located

in the visceral surface

what duct does the gallbladder drain bile into

cystic duct

what structure does the cystic duct join with

common hepatic duct

the cystic duct joins with the common hepatic duct to form which structure

common bile duct

where does the common bile duct lead

major duodenal papilla

role of bile

fat emulsification

composition of bile

water, bile salts from cholesterol, cholesterol, bilirubin, ions

what percentage of bile salts are reabsorbed from bile and recycled in the ileum

90%

as an excretory product, what is the role of bile

excretion of bilirubin (breakdown of RBCs)

what cells release cholecystokinin

intestinal enteroendocrine cells

what does CCK do once released

relaxes the hepatopancreatic sphincter and stimulates gallbladder contraction = increases bile delivery to the duodenum

describe what happens to CCK when the duodenum is empty

not released, hepatopancreatic sphincter closes, gallbladder fills with bile

what happens to old RBCs

broken down by macrophages in the spleen, liver, or red bone marrow

what two products does Hb split into

globin, heme

once Hb is split into globin and heme, what happens to globin

broken into amino acids and reused for protein synthesis

once Hb is split into globin and heme, what happens to heme

iron removed, and then its converted to biliverdin and then to bilirubin

when iron is removed from heme, what happens to it

binds to transferrin and goes it the liver to be stored, or goes to red bone marrow for new RBC production

in the liver, what form is iron stored in

ferritin

once we have bilirubin from heme, it enters the liver and is secreted into bile, bile enters the SI and then the LI. what happens to it in the LI

bacteria convert it to urobilinogen. some is excreted in feces and some is reabsorbed and filtered by the kidneys

describe how new RBCs are formed

in red bone marrow they’re formed using Fe3+, globin, B12, and erythropoietin

describe what happens to bilirubin once heme is broken down

its lipid soluble and binds to albumin and goes to the liver, where it binds to glucuronic acid to form conjugated bilirubin

is conjugated bilirubin water or lipid soluble

water

once bilirubin is conjugated, what happens

able to be excreted in the bile and the kidney

how does jaundice occur

excess bilirubin in the plasma

what causes a build up of bilirubin that leads to jaundice (2)

impaired bilirubin flow or excessive RBC destruction

list 4 examples of pathology that can cause jaundice

liver inflammation, obstruction of the biliary tree, tumor, hemolytic anemia