Histology of the Paraalimetary Tract

Question 1

Serous or mucinous? parotid

Answer 1

serous

Question 2

Serous or mucinous? sublingual

Answer 2

serous and mucinous

Question 3

Serous or mucinous? submucosa of nose, sinuses, mouth, pharynx, larynx, esophagus

Answer 3

mucinous

Question 4

Functional unit of parotid and pancreas

Answer 4

acinar cells embedded in fat

Question 5

Route of flow in the parotid gland

Answer 5

acini –> striated duct –> intralobular duct –> interlobular duct

Question 6

color of serous gland/cell

Answer 6

dark b/c of protein

Question 7

color of mucinous gland/cell

Answer 7

light blue, fluffy b/c no protein

Question 8

Layout of a pancreatic duct

Answer 8

duct with cuboidal epithelium and a collagen collar

Question 9

What cells in the pancreas secrete bicarbonate?

Answer 9

ductal epithelia (vs. acinar cells which secrete enzymes)

Question 10

Where is the stem cell compartment of the pancreas?

Answer 10

junction of acinar cells and small ducts

Question 11

Which hormones are converted in the liver?

Answer 11

vitamin D, T4–>T3

Question 12

How does liver clear ammonia?

Answer 12

glutamate + NH4+ –> glutamine + H2O, transaminases transport ammonia to kidney for excretion and rest converted to urea

Question 13

How does bile flow in the liver compare to blood flow?

Answer 13

blood: hepatic arteries and portal vein –> flow to central veins via fenestrated cords/sinusoids –> IVC
bile: made in hepatocytes –> bile canalicular system –> bile duct (opposite direction of blood flow)

Question 14

What is a clinical role of the liver capsule?

Answer 14

stretching it causes pain –> symptom of liver disease

Question 15

Portal triad

Answer 15

artery (endothelial wall), portal vein (largest), bile duct

Question 16

T/F hepatocytes can re-enter mitosis

Answer 16

T –> regenerative

Question 17

What holds the liver together?

Answer 17

type III reticular framework + Type I collagen border of portal tracts and central veins

Question 18

Is there collagen in the liver sinusoids?

Answer 18

reticulin only –> type III

Question 19

What is the space of Disse?

Answer 19

The space of Disse (or perisinusoidal space) is a location in the liver between a hepatocyte and a sinusoid. It contains the blood plasma. Microvilli of hepatocytes extend into this space, allowing proteins and other plasma components from the sinusoids to be absorbed by the hepatocytes. Fenestration and discontinuity of the endothelium facilitates this transport.

Question 20

Roles of matrix in liver

Answer 20

structure, signaling

Question 21

Bile production pathway

Answer 21

1. unconjugated bilirubin enters liver and is glucoronidated and secreted into bile canaliculus
2. bile salts are produced from cholesterol and secreted into bile canaliculus
   - -> conjugated bilirubin + salts = bile –> bile duct

Question 22

When can you see a bile canaliculus?

Answer 22

in pathology –> hepatocyte coupling leads to buildup of heme in bile canaliculi

Question 23

Where is GGT located?

Answer 23

external surface/apical aspect of bile canaliculus

Question 24

Where is ALT located?

Answer 24

mostly in cytoplasm

Question 25

Where is AST located?

Answer 25

cytoplasm and mitochondria

Question 26

AST

Answer 26

Aspartate transaminase (AST) also called serum glutamic oxaloacetic transaminase (SGOT) or aspartate aminotransferase (ASAT) is similar to ALT in that it is another enzyme associated with liver parenchymal cells and amino acid production. It is raised in acute liver damage, but is also present in red blood cells, and cardiac and skeletal muscle and is therefore not specific to the liver. The ratio of AST to ALT is sometimes useful in differentiating between causes of liver damage.[5][6] Elevated AST levels are not specific for liver damage, and AST has also been used as a cardiac marker.

Question 27

ALT

Answer 27

Significantly elevated levels of ALT(SGPT) often suggest the existence of other medical problems such as viral hepatitis, diabetes, congestive heart failure, liver damage, bile duct problems, infectious mononucleosis, or myopathy. For this reason, ALT is commonly used as a way of screening for liver problems. Elevated ALT may also be caused by dietary choline deficiency. However, elevated levels of ALT do not automatically mean that medical problems exist.

Question 28

GGT

Answer 28

Although reasonably specific to the liver and a more sensitive marker for cholestatic damage than ALP, Gamma glutamyl transpeptidase (GGT) may be elevated with even minor, sub-clinical levels of liver dysfunction. It can also be helpful in identifying the cause of an isolated elevation in ALP (GGT is raised in chronic alcohol toxicity).

Question 29

Zones of the liver

Answer 29

gradient from portal vein to terminal veins in liver

1. area between/immediately adjacent to portal tracts
2. intermediate area
3. star shape emanating from terminal venule touching each of the adjacent portal tracts

Question 30

Features of gallbladder

Answer 30

honey comb surface–> epithelium, lamina, muscularis propria