Histology of Accessory Digestive Organs Flashcards
1
Q
What are the three main diestive glands (general)?
A
- Major salivary glands
- Exocrine pancreas: secreting alkaline aqueous and enzymatic product into duodenum
- Liver: endocrine and exocrine gland with extensive acces to blood circulation
2
Q
Describe the orgtanization of salivary glands.
A
- CT capsule with a septa dividing the gland into lobes and smaller lobules
- Secretory cells are organized into an acinus producing saliva via ANS, myoepithelial cells help release it via ducts
- Acinus–>intercalated duct–>striated duct–>excretory duct
3
Q
What is the pathway for saliva to flow, and what epithelium makes up each duct?
A
- Acinus
- Intercalated duct made of low cuboidal
- Striated duct made of simple cuboidal to columnar
- Excretory duct made of simple cuboidal, psuedostratified or stratified cuboidal
4
Q
What is this what does it consist of?
A
- Parotid gland
- Acini have serous secretory cells
- pyramidal cells with a basal nuclei
- Prominent RER in basal region
- secretory granules are visible in apical region
5
Q
what is this
A
parotid
6
Q
what is this what does it consist of
A
- Sublingual gland
- Mixed but predomiinantly mucous
- branched tubule alveolar gland
- lacks a defined capsule but divided into small lobes by CT
- Intercalated and striated ducts poor developed
7
Q
What is this what does it consist of
A
- submandibular gland
- serous ccells predominant but mucous are present
- serous demilunes
- intercalated ducts short and striated ducts are longer than those in parotid gland
8
Q
what is this
A
sublingual gland
9
Q
Describe the organization of the pancreas?
A
- Bulkl of gland is exocrine but endocrine is present also
- Thin layer of loose CT forms a capsule and divides gland into lobules, neurovasculature and ducts found w/n septa
- exocrine portion synthesizes secretes enzymes for digestion
*
10
Q
What is this?
A
pancreas with acinar cells and centroacinar cells
11
Q
What do centroacinar cells do and where are they?
A
- Found in the pancreas acinar cells
- Seceret bicarb sodium and water alkalinizes secretions, continuous with low cuboidal epithelium of the intercalated duct
- Stain lightly
- (acinar stains intensely)
12
Q
Pancreatic acinar cells?
A
Well developed RER prominent golgi apical domain of zymogen granules
13
Q
Within the pancreatic acinar cells, what do the zymogen granules contain?
A
- Trypsinogen chymotrypsinogen for protein digestion
- Amylolytic enzymes for carb digestion
- LIpase for lipid digestion
- Deoxyribonuclease ribonuclease for nucleic acid digestion
14
Q
what is this
A
pancreas
15
Q
what is this
A
Pancreas
identify islets of langerhans if confusing with parotid gland
16
Q
What is this
A
pancreas
lookofor faint cytoplasm and dark nucleus, these are centroacinar cells
17
Q
Describe organization of liver
A
- enclosed within a thin CT capsule lined with mesothelium of visceral peritoneum, which is lacking where the liver attaches directly to another organ
- Structure of liver varies depending on the functional unit, hepatic lobule, portal lobule and liver acinus
18
Q
What do hepatocytes do?
A
- Metabolism
- nutrient storage
- bile production and secretion
19
Q
How are hepatocytes arragned?
A
NOT acine, they are arranged in cellular cords
liked stacked plates
20
Q
What is the relationship to bile and hepatocytes?
A
- Hepatocytes secrete bile which is a mix of water bile salts and pigments, phospholipids and electrolytes
- The bile drains into bile canaliculus which are spaces between hepatocytes
21
Q
What is indicated by the arrows?
A
Bile canaliculi, spaces between hepatocytes for bile collection
22
Q
What is the structure/fxn relationship for hepatic lobule, portal lobule and hepatic acinus?
A
- Hepatic lobule drains blood from portal vein and hepatic artery to central vein
- portal lobule drains bile from hepatocytes to bile duct
- Hepatic acinus supplies oxygen to hepatocytesHo
23
Q
How is liver parenchyma organized?
A
- Heptic lobules
- Hepatocytes form irregular plates radiating from a central vein and plates are supported by reticular fibers and separated by sinusoids
24
Q
What does the portal triad include?
A
- Branch of hepatic artery
- Branch of portal vein
- Bile ductules
25
Describe the flow of blood and bile in the hepatic lobule?
They flow in opposite directions
26
How do we collect bile?
* Bile collects in bile canaliculi which are interconnected channels formed by hepatocyte plates and tight junctions
* Bile canaliculi drain into **canals of hering** once they are full, they are composed of cuboiodal epithelial cells called **cholangiocytes**
27
Describe the flow of bile.
* Bile canaliculi
* canals of hering
* bile ductules
* merge and enlarge forming right and left hepatic ducts
28
What makes up the Biliary tree?
* Hepatic, cystic and common bile ducts lined with a mucous membrane and a simple columnar epithelium made of cholangiocytes
* cystic duct has areas with mucous glands
* Muscularis layer of the ducts becomes hticker near the duodenum forming the sphincter regulating flow into duodenum
29
Describe hepatic sinusoids
Anastamosing capillaries that deliver portal and arterial blood to hepatocytes
30
What are Kupffer cells?
* Stellate macrophages w/n endothelium of sinusoids, they are larger than endothelial cells
* They detect and phagocytose defective RBCs
* Distinguishes the hepatic sinusoids
31
What are hepatic stellate cells?
* Cells wit hsmall lipid droplets tha store vitamin a and other fat soluble vitamins
32
What is the perisinusoidal space?
* located btw hepatocytes and sinusoidal endothelium and it facilitates uptake and release of nutrients proteins and potenetial toxins
* creates a potential space for exchange of materials btw blood and hepatocytes
* Microvilli projectr into the space
* plasma fills and bathes microvili
* increase surface area available for materail exchange
33
What is the periportal space?
52 min slide65
34
What is the portal lobule?
* Central axis is the bile duct (portal triad)
* find the portal triad by drawing lines btw 3 central veins to make the portal lobule
* triangle outlines bile drainage path from adjacent lobules into same bile duct
35
What is the hepatic acinus?
* Diamond shape and occupies parts of adjacent classic lobules
* find two adjacent central veins with portal triads in between
* Each zone shows how much blood and nutrients are sent
* zone 1 most blood
* This explains distribution of liver damage resulting from ischemia or exposure to toxins, zone 3 will be damaged the most as it already has the least amount of flow
36
What is this and the hallmarks?
Gallbladder
* No muscularis mucosa or submucosa
* Muscularis with bundles of mm fibers oriented in all directions to allowing emptying of organ
* External adventitia where it is against liver and serosa where its exposed to peritoneal cavity
37
Describe what is seen
* Rokitansky-Aschoff sinuses, deep divertiula of the mucosa that may extend through the muscularis externa
* They develop as a result of hyperplasia nad herniation of epithelial cells through the muscularis externa
* Bacteria may accumulate causing chronic inflammation and increased risk for gallstones
38
Differentiate these.
Right is parotid and left is submandibular
39
Differentiate these
* Left: Submandibular glands, you can see the prevalance of serous acini and serous demilunes and few mucous cells
* ID is intralobular ducts
* Right: Sublingual glands, you can see a high amount of mucous cells and skeletal muscle
* ID is intralobular ducts
40
what is this
liver hepatic lobule
41
What is this?
hepatic lobule
42
Label
* Blue: mucous acini
* Red: serous acini
* Duct
Submandibular gland
43
label
1. serous acini
2. serous demilunes
3. duct
4. mucous acini
44
label
* serous demilune
* mucous acinus
* duct
45
What is this
Sublingual gland
46
What is this
Pancreas
47
parotid
48
Pancreas with islet, duct and acinar tissue
49
liver
