Histology Flashcards
1
Q
mucosa of the large intestine
A
- no villi - straight tubular glands - columnar epithelium
1
Q
what type of blood do sinusoids carry
A
mixture of oxygenated (20%) and deoxygenated (80%)
1
Q
what is the acini of the pancreas
A
balls of exocrine cells of the pancreas with a central duct
2
Q
what constitutes a portal triad
A
- branch of hepatic artery - branch of portal vein - branch of bile duct (and lymphatics)
2
Q
what are the gaps between the endothelium of sinusoids called?
A
space of Disse
2
Q
What are mallory bodies
A
represent massive collapse of cytoskeleton of hepatocytes
2
Q
most common causes of chronic hepatitis
A
B and C
2
Q
explain the staging system of chronic hepatitis
A
1- enlarged portal tracts 2. septa but not much linking between portal tracts 3. portal to portal bridginh 4. network of nodules separated by bands of fibrous tissue
3
Q
what are varices
A
dilated segments of a vein
4
Q
life span of a hepatocyte
A
~150 days
5
Q
2 places that there is a major distinct change in the epithelium of the GIT
A
- between the oesophagus and stomach (non-keratinized squamous epithelium to glandular epithelium) - between the large intestine and the anal canal (glandular epithelium to non-keratinized squamous epithelium)
5
Q
function of bile salts
A
emulsify fat to allow absorption of lipids and lipid-soluble vitamins
6
Q
tell me about what is inside a hepatocyte
A
- prominent rough ER, Golgi and secretory vesicles for protein synthesis - prominent smooth ER for fat and steroid metabolism - many mitochondira - one or two nuclei
6
Q
predominant immune cell involved in hepatitis
A
CD8 T lymphocytes
7
Q
what is within the lamina propria of the mucosa
A
- loose CT - nerves - small BVs - immune cells
8
Q
function of paneth cells
A
secretes anti-microbial peptides
9
Q
how big are the lobules of the liver
A
polygons 0.7 x 2mm
9
Q
symptoms of parenchymal liver failure
A
- hepatic encephalopathy - jaundice - coagulopathy - hypoalbuminaemia - portal hypertension
10
Q
how can you tell that you are in the jejunum
A
no peyers patches or brunners glands
10
Q
histological features of liver damage by paracetamol
A
- zone of coagulative necrosis (ghost cells, hypereosinophilic, no nuclei) in mostly zone 3
10
Q
what does the stage refer to in chronic hepatitis
A
degree of fibrosis
11
Q
where do the cytokines that result in the activation of the Stellate cells come from
A
Kuppfer cells)
12
Q
what happens to the bile salts after they are used in the duodenum
A
they are resorbed and recycled
12
Q
what is cholestasis
A
yellow plugs of material representing bile sitting within dilated biliary caniculi
12
how is the rate of chronic hepatitis determined
by the grade - degree of interface hepatitis
14
what is the enteric nervous system
component of the ANS - neurons in submucous and myenteric ganglia that contains sensory neurons, motor neurons and interneurons
15
where does the bile duct go
to the gall bladder for bile storage
16
organisation of sinusoids
artery and vein give rise to network of capillaries = sinusoids --\> throughout the lobules surrounding each row of hepatocytes --\> converging on central vein
17
What is the distinction between the serosa and adventitia
serosa - fluid secreting to allow organ movement adventitia - does not secrete - attaches it to surrounding structures
18
is cirrhosis diffuse or patchy
diffuse
19
what constitutes chronic biliary disease
primary sclerosing cholangitis primary biliary cirrhosis
20
what does the liver store
iron some vitamins - eg vit A
20
how is bile traversed to the bile duct
through canaliculi between hepatocytes (flows outwards towards the bile duct in the portal triad)
20
definition of cirrhosis
nodules of regenerating hepatocytes surrounded by bands of fibrous tissue
21
what type of epithelium does the bile duct have
columnar epithelium
21
what is the portal lobule model
the portal triad is the centre of the lobule with central veins on the periphery - focus is on the direction of BILE flow (triangle)
22
what is the muscularis mucosae
thin layer of smooth muscle forming the boundary of the mucosa
22
what is a councilman body
hepatocyte undergoing apoptosis
22
normal role of Stellate cells
store vitamins (major site of vitamin A)
23
where are mucus cells found in the gastric glands and what do they look like
near the top, clumped together, look pale
25
3 distinguishing features of the oesophagus
- non keratinized squamous epithelium - submucosal glands - two muscle types (striated at the top - voluntary, and then smooth at the bottom - involuntary)
27
histological distinguishing feature of the large intestine
- muscularis externa - 3 bundles of longitudinal muscle (teaniae coli) in the colon - more goblet cells in rectum
28
how many percentage does the endocrine pancreas constitute
1-2%
29
how does an overdose of paracetamol cause liver damage
caused by toxic metabolite (NAPQI) which directly injues hepatocytes and causes depletion of glutathione (a natural anti-oxidant) and therefore leads to oxidative injury and COAGULATIVE NECROSIS
30
what is the pathogenesis of cirrhosis
under chronic inflammation - Stellate cells change to activated phenotype and under the influence of cytokines they produce collagen --\> fibrosis
31
4 main ways for the pathogenesis of portal hypertension
- splanchnic circulation hyperdynamic --\> increased portal vein and hepatic arterial blood flow causing contraction smooth muscle and stellate cells - hepatic vein is directly compressed by regenerating nodules - small portal vein branches are trapped, narrowed and distorted by scar tissue - hepatic arterial blood shunts into portal vein via anastomoses in fibrous septa
32
how are bile salts made
synthesised from cholesterol
33
what type of collagen is the CT of the liver
reticular fibres - types 1 and 3 (surround and support hepatocytes, but not very much - mostly cells)
34
two types of steatosis
macrovescicular (large droplet) microvesicular (small droplet)
35
function of large intestine
- completes absorption and stores more solid contents - immune cells for protection
36
which acute and chronic hepatitis look identical
acute alcoholic hepatitis NASH
37
function of the submucosal glands of the oesophagus
helps lubricate the food to go down to the stomach
37
clinical definition of acute hepatitis
significant elevation of ALT less for than 6 months in someone without previous liver disease
39
what is the cool thing about the gastric glands in the stomach
they vary between the cardia, corpus and pylorus
40
distribution of parietal cells of the stomach
- mostly in the corpus/body - only a few in the pyloric region - none in fundus or cardiac regions
40
distribution of mucous cells of the stomach
lots in the cardiac region some in the body/corpus
41
what does the endocrine pancreas secrete
insulin and glucagon for glucose and energy metabolism)
42
what is macrovesicular steatosis caused by
increased TG synthesis or decreased excretion
43
histological characteristics of alcoholic hepatitis (7)
- Mallory bodies - fat vacuoles - neutrophil infiltration - hepatocellular ballooning - deposition of collagen around hepatocyte plates - fibrosis around the central vein - cholestasis
45
epithelial cells of the small intestine
enterocytes goblet cells enteroendocrine cells paneth cells stem cells
46
tell me about the cells of the exocrine pancreas
- basal region has high density of rough ER and stains blue on H&E - lumenal surface has numerous zymogen granules containing inactive digestive enzymes and stains pink on H&E
46
what is the major form of cell death in chronic hepatitis
apoptosis
47
where are Stellate cells found
live in the space of Disse
47
definition of portal hypertension
- absolute increase in the BP within the portal vein to \>8mmHg - increase in the pressure gradient between the portal vein and hepatic vein of 5mmHg or more
48
types of cells in the gastric glands
- mucus - parietal (HCl secreting) - chief (pepsinogen secreting) - enteroendocrine (gastrin hormones)
49
what are peyers patches
aggregates of immune cells
50
what is Non-alcoholic steatohepatitis
steatosis with steatohepatitis and fibrosis
52
distinguishing features of duodenum
- Brunners glands - receives secretions from the gall bladder and pancreas - low plica circulares and long villi
53
what is in the exocrine secretions of the pancreas
- proteases - lipases - amylases - nucleases - bicarbonate ions
55
what is the classic lobule model
the central vein is in the centre of the lobule with the portal triads at the periphery. - focus is on the direction of BLOOD flow into the central vein (polygonal)
57
common features throughout the GI tract
- mucosa - submucosa - muscularis externa - serosa/adventitia - neurons - immune cells
57
definition of chronic hepatitis
persistence of liver injury with raised serum aminotransferase levels for \>6 months
58
distribution of chief cells of the stomach
only in the body/corpus
59
what is septal fibrosis in chronic hepatitis
bands of fibrosis that radiate in a stellate fashion outwards from the portal triad into the parenchyma
60
what are hepatocytes organised into?
lobules around blood vessels
61
fibrosis pattern in chronic hepatitis
septal fibrosis
63
Distinguishing features of the stomach
- gastric glands - external muscle has 3rd oblique layer - pyloric sphincter
65
function of the crypts of Lieberkuhn
secrete fluid and mucus
66
features of sinusoids
- larger than other capillaries - discontinuous lining
67
what are Kupfer cells
macrophages on the inner walls of sinusoids
68
greatest risk of hepatocellular carcinoma is due to
cirrhosis due to alcohol, chronic viral hepatitis (B and C), haemochromatosis
70
Where are parietal cells found in the gastric glands
never at the surface
71
in which histological layer are the myenteric ganglia found
between the inner and outer layers of the muscularis externa
72
what allows bile to enter the duodenum
sphincter of Oddi stimulated by CCK (which in turn is stimulated by the presence of fat in the duodenum)
74
what are the primary tissue types in the liver
hepatocytes sinusoids CT fibrous CT capsule serous external surface
76
what do the central veins carry blood to
the hepatic vein --\> out of the liver
77
what are the major associations with NAFLD
obesity metabolic syndrome diabetes
78
distribution of endocrine cells in the stomach
- lots in the pyloric region - few in the corpus/body - none in the cardiac or fundus
79
epithelium of the oesophagus
non-keratinized squamous epithelium
80
what produces bile
hepatocytes
80
initial histological signs of chronic hepatitis
- portal triad infiltrated by lymphocytes - lymphocytes spilling across the edge into the peri-portal tissue = interface hepatitis
82
epithelium cells of the mucosa
- columnar enterocytes or stratified squamous - endocrine cells - stem cells
83
what is non-alcoholic fatty liver disease
steatosis - with or without steatohepatitis and fibrosis
84
3 main steps of cirrhosis
- chronic liver cell apoptosis and inflammation - ECM deposition (fibrosis) - remodeling of the liver vascular supply
86
histological features of lobular disarray (that happens in acute viral hepatitis A and B) (6)
- lymphocyte infiltration - liver hepatocyte swelling - cells not organised in any arrangement - hard to see sinusoids - enlarged Kupffer cells containing bile and lipofuschin - APOPTOSIS = Councilman bodies
87
main conditions associated with the 3 general causes of portal hypertension
- presinusoidal - portal vein thrombosis - intrahepatic/sinusoidal - cirrhosis - posthepatic - thrombosis of hepatic veins
88
what do portal triads supply
multiple lobules
89
why are there more goblet cells in the large intestine
need for lubrication is higher as the contents are more solid
91
what are the 3 lobule models
- classic lobule model - portal lobule model - acinar lobule model
92
where is the position of zone 3 in relation to central vein and portal triad
- furthest from portal triad - closest to the central vein
93
what are the hormone secreting cells of the pancreas called
Islets of Langerhans
94
acute alcohol hepatitis and alcoholic liver disease are both characterized by
tissue injury pattern of steatohepatitis
96
epithelium of the gall bladder
simple columnar epithelium - specialised for absorption of water to concentrate bile
97
what are the 3 patterns of acute
- lobular disarray and apoptosis = acute viral hep A and B - zonal coagulative necrosis = parecetemol toxicity - mallory bodies, neutrophils = alcoholic hepatitis
99
what is the acinar lobule model
- focuses on the different oxygenation and metabolic function - zones 1-3 with zone 1 having the highest O2, toxins and nutrients and zone 3 having the lowest (semi-circle)
100
where are the peyers patches located
in the submucosa
101
most clinically important sight of varices in someone with portal hypertension
oesophageal
102
3 major signs of portal hypertension
- ascites - splenomegaly - varices at site of portal-caval anastomoses
104
which liver enzyme instantly indicates acute hepatitis
ALT very high
105
comparison of the epithelia between small and large intestine (4)
- no villi in L - paneth cells are rare in L - higher proportion of goblet cells in L - some differences in enteroendocrine cell types
106
what can help the movement of the villi in the GI
smooth muscle in the lamina propria muscularis mucosae within
108
epithelial cells of the large intestine
- enterocytes - goblet cells - enteroendocrine cells - stem cells
109
what is a common coagulation disfunction that occurs with liver failure
thrombocytopanenia
110
what can happen after extensive liver repair to the structure of the liver
regenerated liver tissue may not have same lobular structure and is more fibrous
111
what part of the liver is swelled in viral acute hepatitis
entire lobule and portal triads
112
7 causes of cirrhosis
alcoholic liver disease, NASH, chronic viral Hep B and C, autoimmune hepatitis, chronic biliary disease, metabolic, drugs
114
what proteins does the liver make
plasma proteins lipoproteins
115
muscle layers in the muscularis externa
usually 2 layers - inner circumferential - outer longitudinal --\> 3rd layer in the large bowel and stomach
116
function of gall bladder
stores bile concentrates the bile, removing water and sats
117
2 categories within the enteric nervous system
- submucous ganglia = absorption and secretion - myenteric ganglia = smooth muscle activity
118
what is within the submucosa
dense, irregular CT containing nerves, small ganglia and blood vessels. - sometimes contains glands and immune cells
119
flow of blood in sinusoids is in which direction
outside --\> in to central vein
120
where are the enteroendocrine cells found in the gastric glands
scattered throughout the gland
122
layers of the mucosa
epithelium lamina propria muscularis mucosae
124
functions of the small intestine
- completes digestion with assistance of local enzymes, pancreatic and gall bladder secretions - responsible for most of the absorption - immune cells for protection
125
how is surface area increased in the small intestine
plica circulares villi microvilli
126
main constituents of bile
bile salts (surfactants) and bile pigments
127
what is the hallmark feature of steatohepatitis
hepatocellular ballooning degeneration
129
5 functions of the GI tract
- digestion - absorption - secretion - movement - protection
130
small intestine distinguishing features
- crypts of Lieberkuhn - villi
131
how are bile pigments formed?
due to breakdown products
132
primary functions of the liver (broadly)
metabolism absorption of fats - bile protein synthesis storage detoxification
133
distinguishing features of the ileum
- peyers patches - short villi, more goblet cells
134
definition of interface hepatitis
periportal inflammation
135
what allows exocrine pancreatic secretions into the duodenum
the sphicter of Oddi
136
what is the hallmark of permanent damage of the liver
cirrhosis and atropy
137
where does the apoptosis occur in chronic hepatitis
at the interface between portal triad and lobular parenchyma
138
what is steatosis
accumulation of abnormal amounts of lipid in hepatocytes
139
what is the importance of zone 3 in the liver
it is vulnerable to a wide range of toxins and to ischaemia
