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Histology: Winter Quarter > Histology of the Pancreas & Liver: Week 1 > Flashcards

Histology of the Pancreas & Liver: Week 1 Flashcards

1
Q

General details about the pancreas are…

A

Location: lies against posterior abdominal wall; retroperitoneal

Anatomical regions: uncinate process, head, body, tail

Division: septa (CT) subdivides pancreas into lobules; septa contains nerves & vessels

Function: exocrine and endocrine

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2
Q

The exocrine pancreas produces ___ ml of fluid per day, and the fluid contains digestive ____

A

1200, proenzymes

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3
Q

The functional unit of the exocrine pancreas is the___

A

pancreatic acinus

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4
Q

Each pancreatic acinus is formed of __ to __ acinar cells and each acinus usually contains 3-4 ____ cells

A

40 -50
centroacinar
*centroacinar cells are the beginning of the duct system

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5
Q

Features of acinar cell,for example shape etc.

A

Shape: pyrimidal shape

location: sits on basal lamina

cytoplasm: basophilic & apical secretory granules

Basal membrane: receptors for cholecystokinin

abundant in rER, polysomes, mitochondria

Well developed Golgi

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6
Q

Acinar cells are stimulated by …

A

secretin to produce fluid high in HCO3-

cholecystokinin to secrete proenzymes

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7
Q

What type of innervation stimulates both acinar and centroacinar cells?

A

Parasympathetic

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8
Q

Pancreatic enzymes include…

A
  • pancreatic amylase
  • pancreatic lipase
  • ribonuclease and DNase
  • trypsinogen, chymotrypsinogen, procarboxypeptidase, elastase
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9
Q

Centroacinar cell features

A
  • Squamous to low cuboidal cells
  • have receptors for secretin
  • form the intra-acinar portion of intercalated ducts
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10
Q

Intercalated ducts begin __, and are named based on__ ? What kind of epithelium do they have?

A
  • Begin in acini
  • named for location between acini
  • simple cuboidal epithelium
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11
Q

Interlobular ducts are made up of what kind of epithelium and cells?

A

simple low columnar epithelium, with
enteroendocrine and goblet cells

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12
Q

Main pancreatic duct joins__ __ duct. What kind of epithelium and cells make up this duct?

A
  • joins the common bile duct
  • simple columnar epithelium with goblet cells
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13
Q

Features of Pancreatic Islets (of Langherhans)…

A
  • ~ 1,000,000 islets per pancreas
  • richly vascularized spherical groupings of ~ 3,000 cells
  • most abundant in the tail region of the pancreas
  • surrounded by and pervaded by reticular fibers
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14
Q

Cells of Pancreatic Islets

A

β - cells: produce insulin and amylin
α - cells: produce glucagon
δ - cells: produce somatostatin
G cells: produce gastrin
PP cells (F cells): produce pancreatic polypeptide

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15
Q

Pancreatic hormone: Insulin…steps of formation

A
  1. produced as pre-proinsulin in RER
  2. converted to proinsulin in RER cisternae
  3. converted to insulin in Golgi, packaged for export
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16
Q

Insulin…why is it released and what does it do?

A

released due to increase in blood glucose

increases cell permeability to glucose; cell uptakes and stores glucose

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17
Q

Pancreatic hormone: Glucagon…why is it released and how is it produced?

A
  • released in response to low blood glucose
  • produced as a prohormone which undergoes proteolytic cleavage
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18
Q

Glucagon acts on ____ to activate what?

A

hepatocytes, glycogenolysis

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19
Q

Glucagon causes what mechanism to help remove glucose?

A

hydrolytic enzymes, released into the bloodstream, break down glucose

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20
Q

Glucagon activates what process in the liver?

A

gluconeogenesis

21
Q

Pancreatic hormone: Somatostain… why is it released?

A

released due to increases in blood glucose, aa’s or
chylomicrons

22
Q

What are the functions of somatostatin/what does somatostatin do?

A
  1. inhibits the release of hormones by α - cells and β –cells
  2. suppresses exocrine secretion of pancreas
  3. reduces motility of smooth muscle in digestive tract & gallbladder (inhibits secretion of digestive hormones)
23
Q

Pancreatic hormone: Gastrin

A

realsed by G cells

24
Q

Gastrin stimulates what 3 functions?

A
  1. gastric release of HCl
  2. gastric motility and emptying
  3. cell division of gastric regenerative cells
25
Q

Pancreatic hormone: pancreatic polypeptide…what is it released by and what does it regulate?

A
  • released by PP cells
  • helps regulate both endocrine and exocrine secretions of the pancreas
26
Q

Liver: General things to consider

A
  • weighs ~ 1500 g
  • located in upper right quadrant of abdominal cavity
  • has both endocrine and exocrine function
  • site of detoxification of drugs and toxins
27
Q

Glisson’s capsule functions in what way in relation to the liver?

A

is dense irregular CT that covers the liver

28
Q

The hilum of the liver is called ___ and it is where ___, ___,and ___ enter.

A

Porta hepatis; blood, lymph vessels, bile ducts

29
Q

The primary cell type of the liver is ___ and they form ___

A

Hepatocytes, lobules

30
Q

What are the 3 types of liver lobules?

A
  1. Classical Liver Lobule (aka Classic Hepatic Lobule)
  2. Portal Lobule
  3. Portal Acinus (Hepatic Acinus)
31
Q

What are the features of the classic liver lobule?

A
  • central vein forms
    longitudinal axis
  • portal areas contain portal
    v, hepatic a, and bile
    ductule
  • hepatocyte cords radiate
    from center
  • sinusoids found between
    hepatocyte cords
  • blood percolates from
    portal areas to central vein (moving from outward to inward)
  • central vv –> sublobular vv
    –> collecting vv –> hepatic
    vv
    LOBULE HAS HEXAGONAL SHAPE

drains blood from portal vein and hepatic artery to hepatic or central vein

32
Q

What are the features of the portal lobule?

A
  • describes pattern of bile
    flow to interlobular bile
    ducts
  • center of portal lobule is
    portal area
  • periphery is imaginary
    line that connects three
    central veins
    TRIANGULAR IN SHAPE

Drains bile from hepatocytes to bile duct

33
Q

What are the features of the portal acinus lobule?

A
  • based on blood flow
    from distributing
    arteries
  • indicates the order in
    which hepatocytes
    degenerate due to
    toxicity or hypoxia
  • divided into three zones
    of decreasing
    oxygenation

RHOMBOIDAL IN SHAPE

Zone 3 least oxygenated, Zone 2 , Zone 1 most oxygenated

Supplies oxygenated blood to hepatocytes

34
Q

What are sinusoids and their components?

A

large-diameter fenestrated vessels, lined by endothelium

contains Kupffer cells (macrophage-like
phagocytes)

has a perisinudoisal space
(space of Disse) separates
sinusoids from hepatocytes
* hepatic stellate cells (Ito
cells) contain vitamin A and
fat droplets

Hepatocytes, Space of Disse (perisinusoidal space), and Sinusoid

35
Q

Sinusoids are surrounded by plates of ___?

A

Hepatocytes

36
Q

Flow of bile (Hepatic ducts)

A
  1. bile canaliculi anastomose with one another
  2. canaliculi transition to canals of Hering (also
    called cholangioles)
  3. canals of Hering empty into interlobular bile
    ducts that merge to form larger ducts
  4. these lead to right and left hepatic ducts
37
Q

Hepatocytes are __ in shape and__-__ um (micrometers
in diameter)

A

polygonyl,20-30

38
Q

Hepatocytes have a membrane with the following lateral domains: form bile canaliculi isolated by __ __; also have gap junctions, __ increase surface area for bile secretion and its walls of canaliculi are rich in __ and __.

A

fasciae occludentes, microvilli, Na+-K+ATPase and
adenylate cyclase

39
Q

Hepatocytes have a membrane with the following sinusoid domain: have microvilli projecting into
__ __,release __
secretions, and exchange between __ and hepatocyte
takes place.

A

perisinusoidal space
(of Disse), endocrine, blood

40
Q

Organelles found in hepatocytes are:

A
  • nucleus: single or double and diploid or polyploid (up to 64 N

abundant free ribosomes, RER and
Golgi
* up to 2,000 mitochondria per cell
(more abundant near central v)

  • abundant endosomes, lysosomes, peroxisomes
  • SER, especially rich in
    zone 3, detoxifies blood
  • Inclusions
    – lipid droplets ( mostly
    VLDL)
    – glycogen (β particles)
    located near SER
41
Q

Role of the liver is to…

A

manufacture bile, 600 to 1200 ml per day

42
Q

Bile is made up of…

A

H2O, bile salts, phospholipids, cholesterol, bile
pigments, IgA

43
Q

What are the 2 methods for making bile salts?

A

– are reabsorbed from lumen of small intestine
– or formed de novo in the SER of hepatocytes

44
Q

What are the bile pigments?

A

– bilirubin: water-soluble, yellow-green, toxic degradation product
of hemoglobin

– biliverdin, phycobilin, phycobiliprotein, phycoerythrobilin,
stercobilin, urobilin

slide 43

45
Q

Another funtion of the liver is to metabolize organic substances: Lipids…what are the steps of lipid metabolism in the liver?

A

– chylomicrons from digestion enter lymphatic system
– these reach the liver via hepatic artery
– broken into glycerol and fatty acids
– fatty acids used to make phospholipids and
cholesterol or acetyl CoA
– acetyl CoA used to make ketone bodies
– hepatocytes manufacture VLDLs
– phospholipids, cholesterol, ketone bodies, and VLDLs
released into space of Disse, as needed

46
Q

Another funtion of the liver is to metabolize organic substances: Carbohydrates

A

– maintains normal blood glucose levels by:
» taking in and storing glucose as glycogen
» glucose reformed by glycogenolysis as needed
» gluconeogenesis: formation of glucose from other
molecules

47
Q

Another funtion of the liver is to metabolize organic substances: Proteins
– hepatocytes manufacture ~__% of blood proteins
» blood clotting factors
» complement proteins
» transport proteins
» albumins
– hepatocytes manufacture __ (except __ __)
– hepatocytes manufacture ___
– hepatocytes convert __ to __

A

~90%, globulins (except gamma
globulins), non-essential amino acids, ammonia, urea

48
Q

Other roles of the liver are…vitamin storage of? degradation of?

A

– vitamin storage: A, D, B12
– degradation of hormones by lysosomal enzymes
– degradation of drugs and toxins (in SER or peroxisomes)
* methylation
* conjugation
* oxidation

49
Q

Liver has role of immune funciton…

A
  • release of IgA in bile
  • Kupffer cells phagocytose foreign particulate
    matter

Histology: Winter Quarter (3 decks)

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