Liver Flashcards

(208 cards)

1
Q

what is the diaphragmatic surface

A

anterolateral = contains bare area

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2
Q

what is the visceral surface

A

posteroinferior = covered with peritoneum, except gallbladder/porta hepatis

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3
Q

what is the bare area of the liver

A

large triangular area on diaphragmatic surface = no peritoneum

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4
Q

what is the falciform ligament

A

double fold of peritoneum = forms a natural anatomical division of right/left lobe of liver and attaches liver to diaphragm

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5
Q

what is the ligamentum teres

A

free edge of falciform ligament = remnant of umbilical vein

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6
Q

what are the coronary ligaments

A

attach the superior surface of liver to posterior diaphragm = anterior/posterior

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7
Q

what are the triangular ligaments

A
left = union of anterior/posterior layers of coronary ligament at apex of liver = left lobe to diaphragm
right = attaches right lobe to diaphragm
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8
Q

what is the functional division of the liver

A

line down gall bladder/ivc

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9
Q

what is the porta hepatis

A

point of entry into liver for hepatic arteries and portal vein/exit for hepatic ducts

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10
Q

where is calot’s triangle

A

at porta hepatis

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11
Q

what are the contents of calot’s triangle

A

right hepatic artery
cystic artery
lymph node of Lund
lymphatics

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12
Q

what is the liver’s fibroud layer known as

A

glisson’s capsule

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13
Q

what supplies blood to the liver

A

25% hepatic artery proper from coeliac trunk to non-parenchymal structures
75% hepatic portal vein

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14
Q

wha tdoes the hepatic portal vein supply the liver with

A

partially deoxy blood + nutrients from small intestine to liver parenchyma = allows detoxification

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15
Q

what does the portal triad contain

A

proper hepatic arterioles
hepatic portal venules
bile ducts

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16
Q

what are the structural units of the liver

A

lobules

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17
Q

what are the functional units of the liver

A

acini

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18
Q

what are acini

A

divided into zones according to distance form arteriole blood supply = hepatocytes closest better oxygenated

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19
Q

what is the nerve supply to the liver

A

parenchyma = hepatic plexus = sympathetic (coeliac plexus) and parasympathetic (vagus)

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20
Q

what is the nerve supply to glisson’s capsule

A

lower intercostal nerves

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21
Q

with what organs does the pancreas have anatomical relations

A
stomach
duodenum
transverse mesocolon
common bile duct
spleen
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22
Q

what vessels is the pancreas associated with

A

aorta/IVC posteriorly
superior mesenteric artery behind neck
hepatic portal vein behind neck
splenic artery travels superior border

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23
Q

describe the duct system of the pancreas

A

acini connected by intercalated ducts = unite into lobules = drain into intralobular collecting ducts = become main pancreatic duct

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24
Q

what forms the hepatopancreatic ampulla of vater

A

pancreatic duct unites with common bile duct

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25
what is Hartmann's pouch
mucosal fold in neck of gallbladder = common site for gallstone lodging
26
what supplies blood to the gallbladder
cystic artery
27
what is the venous drainage of the gallbladder
cystic veins to portalto portal vein
28
what structures are found in the porta hepatis
portal vein r/l hepatic artery r/l hepatic duct microscopically = lymphatics/vagus nerve branches/greater splanchnic nerves branches
29
where is the bare area of the liver
under central tendon of right side of diaphragm
30
what is the surface marking of the fundus of the gall bladder
tip of 9th costal cartilage | where midclavicular line crosses costal margin
31
what degenerates to become ligamentum venosum
ductus venosus
32
what innervates the gall bladder
coeliac plexus = sympathetic and sensory fibres | vagus nerve = parasympathetic innervation
33
where would disease of gall bladder be felt
rubbing on diaphragm so pain carried by c3,4,5 = right shoulder
34
where do hepatic veins drain
IVC
35
which fat soluble vitamins are stored in the liver
KADE
36
what substances are stored in the liver
iron glycogen minerals fat soluble vitamins
37
where is iron used
haemoglobin myoglobin bone marrow
38
name 4 sources of iron
meat liver egg yolk shell fish
39
how much of ingested iron is absorbed in duodenum
about 10% = changes according to needs
40
what is ferritin
protein-iron complex acting as intracellular store for iron in kupffer cells in liver
41
how does iron travel in the blood
bound to transferrin
42
what cells in the liver store iron
kupffer cells
43
what 2 things occur when body has reached iron capacity
1. increased free iron in plasma/intestinal epithelial cells = increased ferritin production = increased iron binding and therefore reduce amount released into blood 2. hepatocytes release hepcidin = inhibits ferroportin so reduce amount of iron in blood
44
what occurs when iron is absorbed
1. actively transported into duodenal enterocytes 2. then incorporated into ferritin and stored intracellularly 3. most bound to ferritin = released back to lumen and excreted in faeces 4. absorbed iron not bound to ferritin = released into blood via ferroportin then bind with transferrin 5. iron bound to transferrin = to liver
45
what occurs when iron stores are low
production of intestinal ferritin decreases = decrease amount of iron bound to ferritin = increase free iron released into blood
46
what is the most abundant plasma protein
albumin
47
what are the functions of albumin
1. binding/transport of large, hydrophobic compounds = bilirubin/FA/hormones/drugs 2. maintenance of colloid osmotic pressure
48
what is colloid osmotic pressure
effective osmotic pressure across blood vessel walls permeable to electrolytes but not large molecules = almost entirely due to plasma proteins
49
how does albumin maintain the osmotic pressure of the blood
presence in blood = water conc is lower than in interstitial fluid = net flow of wate rout of interstitial fluid into blood plasma
50
what are the 4 starling forces
1. capillary hydrostatic pressure = fluid out of cap 2. interstitial hydrostatic pressure = fluid into cap 3. osmotic force due to plasma protein conc = fluid into cap 4. osmotic force due to interstitial fluid protein conc = fluid out of cap
51
what occurs to fluid at the arterial end of capillarires
interstitial fluid has high conc of proteins bc fluid loss to lymphatics so has higher osmotic pressure = bulk fluid filtration out of capillaries into interstitial fluid
52
what occurs to fluid at venous end of capillaries
capillary hydrostatic pressure decrease die to resistance of blood flow but all other starling forces same = bulk fluid absorption into capillaries
53
what causes a decrease in albumin
``` decreased synthesis decreased catabolism increased loss = haemorrhage liver failure nephrotic syndrome = albumin filtered into urine burns ```
54
what is hypoalbuminaemia
decrease of albumin in blood = caused by liver failure = leads to oedema because decreases capillary oncotic pressure
55
what are globulins
work as antibodies = alpha/beta made in liver
56
what is the role of the liver in producing clotting factors
produces all except calcium (IV) and vWF (VIII) | produces bile salts essential for vitamin K absorption
57
what is the role of vitamin K
essential for synthesis of clotting factors 10, 9, 7 ,2 = 1972
58
what are complement factors
= plasma protein | sticks to pathogens = mark for neutrophils for killing
59
what water soluble vitamin is stored in the liver
B12
60
what are xenobiotics
foreign chemical substance not normally found of produced in body which cannot be used for energy requirements = DRUGS = absorbed across lungs/skin/ingested = excreted in bile/urine/sweat/breath
61
describe pharmacologically active compounds
lipophilic = can pass through memranes non-ionised at pH 7.4 bound to plasma proteins to be transported in blood
62
what are microsomal enzymes
enzymes found in small particles consisting of piece of endoplasmic reticulum to which ribosomes are attached
63
where are microsomal enzymes found
on smooth endoplasmic reticulum mostly in liver hepatocytes
64
where are non-microsomal enzymes found
cytoplasm/mitochondria of hepatocytes in the liver (+ other tissues)
65
what processes are microsomal enzymes involved in
oxidative, reductive, hydrolytic mainly phase 1 reactions = biotransform substances can be involved in phase 2 = glucuronidation
66
what are microsomal enzymes induced/inhibited
``` drugs food age bacteria alcohol ```
67
what processes are non-microsomal enzymes involved in
non-specific = can be phase1 or 2 involved in all conjugation reactions NOT in glucuronidation
68
what is the aim of liver detoxification
to transform a drug into less toxic/more water soluble so can be excreted
69
what is the aim of phase 1 reactions
make substance more hydrophilic by adding/exposing a hydroxyl group
70
give 3 examples of non-synthetic catabolic reactions
oxidation reduction hydrolysis = introduce reactive group to drug ready for conjugation
71
give 4 examples of oxidation of drugs
hydroxilation = adding OH dealkylation = remove CH side chains deamination = remove NH hydrogen removal
72
what occurs in hydrolysis
split amide and ester bond
73
what occurs in reduction
addition of a hydrogen
74
what is functionalisation
introducing reactive group to drug/adding/exposing oH, SH, NH2, COOH = occurs mainly in liver catalysed by cytochrome P450 enzyme
75
what are cytochrome P450 enzymes
microsomal in phase 1 uses haem group to oxidise substances = products are more water soluble
76
what is the overall reaction for phase 1 reactions
NADPH + H+ + O2 + RH = NADP+ + H2O + R-OH
77
give 2 examples of non-microsomal enzymes used in phase 1 reactions
alcohol dehydrogenase | aldehyde dehydrogenase
78
what are the outcomes of phase 1 reactions (4)
1. inactivate drugs 2. further activate drug 3. activate drug from pro-drug 4. make drug into reactive intermediate
79
what are phase 2 reactions
synthetic anabolic reactions | = conjugation reactions
80
what is a conjugation reaction
attachment of substituent groups usually inactive products catalysed by transferases = increase hydrophilicity for renal excretion
81
what is a glucuronidation reaction
adding glucuronic acid to make more hydrophilic
82
what enzymes are used in glucuronidation reactions
glucuronosyltransferase (UGT) = microsomal | uridine diphospho-glucuronic acid (UDPGA) = coenzyme for conjugation of glucuronic acid
83
give an example of an active drug to inactive metabolite
phenobarbital to glucuronides
84
give an example of an active drug to active metabolite
codein to morphine
85
give an example of an inactive drug to an active metabolite
loratidine to active drug
86
give an example of an active drug to a reactive intermediate
paracetamol to NAPQI = toxic
87
how is paracetamol metabolised
predominantly via phase 2 glucuronic acid/sulphate conjugation
88
how does paracetamol become toxic
low glucuronic acid/sulphate = undergo phase 1 metabolism via oxidation = NAPQI = removed by glutathione but if low levels glutathione then = toxic!!
89
what is the equation for alcohol metabolism
ethanol to acetaldehyde by ADH acetaldehyde to actetate by ALDH acetate to CO2 + H2O
90
what is protein turnover and degradation
continuous degradation and resynthesis of all cellular proteins = variable and reflects usage/demand
91
when is protein turnover increased
tissue damage pregnancy starvation severe burns
92
what are the 2 primary methods of protein breakdown
lysosomal | ubiquitin-proteosome pathway
93
where does lysosomal protein breakdown take place
through sinusoidal endothelial cells to Kupffer cells
94
describe lysosomal protein degradation through
1. soluble proteins from blood through sieve plates of sinusoid 2. phagocytosed by kupffer cells 3. packeaged into lysosomes in kupffer cells 4. lysozymes breakdown proteins
95
where does the ubiquitin-proteasome pathway take place
cytoplasm of cells
96
describe protein degradation in the ubiquitin-proteasome pathway
1. ubiquitin binds to protein = acts as target for proteosomes 2. proteosome encases protein and destroys it 3. amino acids can be recycled
97
where does amino acid degradation/catabolism take place
in hepatocytes in liver
98
what is amino acid catabolism
nitrogen containing amino group removed to produce nitrogen and carbon skeleton N = excreted/incorporated into other compounds C = metabolised/krebs
99
name the 2 main catabolism processes
oxidative deamination | transamination
100
what is oxidative deamination (in the glucose alanine cycle)
in liver | alanine to pyruvate gives an amine group to alphaketoglutarate to form glutamate
101
what is the enzyme used in oxidative deamination
glutamate dehydrogenase
102
what are the implications of oxidative deamination being a reversible reaction
excess ammonia produced = can cross BBB = react with alphaketoglutarate = decrease ATP = dangerous
103
what is transamination (in the glucose alanine cycle)
transfer of alpha amino group from glutamate to pyruvate to make alanine glutamate goes to alphaketoglutarate
104
what is the enzyme for transamination
alanine aminotransferase
105
where are the enzymes for the urea cycle found
mitochondria/cytosol of hepatocytes
106
describe the urea cycle in 3 steps
1. arginine to ornithine by arginase with generation of urea 2. ornithine to citrulline with addition of ammonia and CO2 (carbomyl phosphate) 3. citrulline to arginine with addition of ammonia
107
what is generated from the urea cycle
urea only (= 2 x ammonia)
108
what occurs if there are enzyme deficiencies of the urea cycle
leads to higher levels of ammonia in blood | no enzymes = no life
109
why is ammonia associated with neurotoxicity
able to cross BBB once inside converted to glutamate (glutamate dehydrogenase) = depletion in alpha-ketoglutarate = oxaloacetate reduces = no krebs cycle = cell damage/death
110
what does 1 cycle of urea cycle consume
3ATP | 4PO4-
111
how is fat stored
``` most = adipocytes forming adipose tissue some = in hepatocytes ```
112
what are lipids
ester of fatty acids and certain alcohol compounds
113
name 3 functions of a lipid
energy reserves structural cell membrane hormone metabolism
114
what is the role of lipoproteins
transport cholesterol in blood
115
what is HDL
high density lipoprotein = formed in liver | removes excess cholesterol from blood/tissue then deliver to liver which secretes as bile/convert to bile salts
116
what is LDL
low density lipoprotein = produced by hepatic lipase in hepatocytes main cholesterol carriers = take to tissues for endocytosis
117
why is LDL bad
high plasma concentrations associated with increase cholesterol deposition in arterial walls
118
why is LDL needed
essential in supplying cells with cholesterol needed for steroid hormone synth/plasma membranes
119
what is VLDL
very low density lipoprotein synthesised in hepatocytes transport triglycerides from liver to tissues
120
how much of the energy used by muscle/liver/kidneys is derived from catabolism of fatty acids
under resting conditions = approx half
121
what is the function of adipocytes
synthesise/store triglycerides during food uptake release FA/glycerol into blood when food not being absorbed from small intestine FA/glycerol in blood for uptake in cells = energy for ATP
122
describe the 4 step process of fat catabolism
1. FA across cell membrane 2. bind to coenzyme A by acyl CoA synthetase to form acyl CoA 3. acyl CoA through mitochondrial membrane by cartinine shuttle 4. in mitochondria = Beta oxidation = 2C removed to repeat cycle and acetyl CoA, NADH, FADH formed for Krebs/oxidative phosphorylation
123
what is the role of lipoprotein lipase
hydrolyses triglycerides in lipoproteins into 3 x FA and 1 x glycerol
124
what is the role of hepatic lipase
converts intermediate density lipoprotein into LDL = packaging with more triglycerides to be released into body
125
where is hepatic lipase found
expressed in liver/adrenal glands
126
where is bile secreted
in liver by hepatocytes continuously
127
what is the role of bile
emulsify fats | excretory pathway for most steroid hormones/drugs
128
where is bile stored
in gall bladder = concentrated bc NaCl/water absorbed into blood
129
what is the space of disse
space separating hepatocytes and sinusoids
130
what are hepatic lobules
wedge-like arrangements of hepatocytes around 1 to 2 cells deep surrounded by sinusoids = mixed portal/hepatic artery blood
131
what are the contents of bile
``` bile salts - mostly cholesterol and waste products lecithin = phospholipid HCO3- bile pigments trace metals ```
132
how is bile stored in the gall bladder
bile salts, cholesterol, lecithin = aggregated to mixed micelles
133
what cells secrete the components of bile
hepatocytes = bile salts, cholesterol, lecithin, bile pigments epithelial cells lining bile ducts = most of HCO3- rich solution = stimulated by secretin
134
describe the production and storage of bile
1. bile produced in hepatocytes 2. transported in micelles through canaliculi 3. actin filaments contract around canaliculi to move bile to hepatic ducts 4. hepatic duct to cystic duct to gall bladder
135
what is the enterohepatic circulation
recycling pathway of bile salts
136
what happens to bile salts during digestion of a fatty meal
most that enter intestinal tract = absorbed by specific Na+ coupled transporters in terminal ileum
137
what happens to absorbed bile salts
returned via portal vein to liver uptake to hepatocytes driven by secondary AT coupled to Na+ then secreted into bile
138
what occurs to lost bile salts
5% lost in faeces | liver synthesises new bile salts from cholesterol
139
what occurs to bile in the fasted state
bile synthesised/recirculated in liver sphincter of Oddi shut bile diverted back to be stored in gall bladder
140
what occurs to bile in the fed state
fat stimulates release of CCK CCK relaxes sphincter of Oddi and contracts gall bladder stored bile shoots into duodenum
141
what is CCK
cholycystokinin
142
describe the role of cholesterol in bile
cholesterol extracted from blood = to liver = secreted into bile solubility achieved by incorporation into micelle
143
what is ezetimibe
enzyme which blocks protein-mediated transport of cholesterol across membrane of cells of wall of duodenum
144
what happens to cholesterol in the digestive system
50% absorbed = bile | 50% excreted in faeces
145
what are bile pigments
substances formed from haem portion of haemoglobin when old/damaged erythrocytes break down in spleen/liver
146
what is bilirubin
predominant bile pigment which is extracted from blood by hepatocytes and actively secreted into bile
147
what colour is biliverdin
green
148
what colour is bilirubin
orange/yellow
149
what colour is stercobilin
gives faeces brown colour
150
what colour is urobilin
responsible for yellow of urine
151
what is jaundice
yellow discolouration of skin caused by high serum bilirubin level
152
what occurs in pre-hepatic jaundice
increased total bilirubin in blood increased unconjugated bilirubin bc exceed amount liver can conjugate enlargement of spleen due to haemolysis
153
what are the clinical signs of pre-hepatic jaundice
normal faeces | normal urine = unconjugated = insoluble so bound to albumin so dont filter into urine
154
what occurs in hepatic jaundice
problem with liver itself = cannot take up/conjugate/excrete bilirubin enlargement of spleen = trying to help liver break down RBCs all levels bilirubin increase = no conjugation + leaky liver decreased urine urobilinogen
155
what are the clinical signs of hepatic jaundice
normal faeces | dark urine = raised conjugated bilirubin but decreased urine urobilinogen
156
what occurs in post hepatic jaundice
= obstruction high conjugated bilirubin bc liver is fine no enlarged spleen increased urine bilirubin
157
what are the clinical signs of post hepatic jaundice
pale faeces | dark urine = increased urine urobilinogen as hepatic system still working
158
name 3 causes of prehepatic jaundice
malaria sickle cell anaemia thalassaemia
159
name 3 causes of hepatic jaundice
liver cirrhosis liver cancer drugs
160
name 3 causes of post hepatic jaundice
gallstones pancreatic cancer gall bladder cancer
161
why do gallstones form
if concentration of cholesterol in bile becomes too high compared to phospholipids/bile salts = cholesterol crystallise out of solution
162
what blood vessel is closely related to the duodenum
superior gastroduodenal artery runs in close proximity to duodenum
163
what does the pancreas secrete
HCO3- | digestive enzymes
164
how do secretions leave the pancreas
secretions arise from acinar tissue = secreted into ducts = converge into pancreatic duct = joins common bile duct = enter duodenum
165
where is the accessory pancreatic duct
emerges above ampulla of vater in duodenum
166
what does HCO3- do
secreted by epithelial cells lining ducts = duct cells protect duodenal mucosa from gastric acid buffers material entering duodenum to pH suitable for enzymes
167
what is the production of HCO3- from pancreas stimulated/inhibited by
stimulated by release of secretin produced in small intestine in response to acid in duodenum secretin also stimulates CCK + inhibits acid secretion/gastric motility of stomach
168
how is HCO3- secreted into the pancreatic duct lumen
by Cl-/HCO3- exchanger
169
describe the process of HCO3- secretion from pancreatic ducts (5)
1. bicarbonate reaction within cell = H+ + HCO3- produced 2. H+ out of basolateral to capillary exchanges for Na+ - H+ to portal vein 3. Na+/K+ATPase pumps K+ in and Na+ out = provide energy for secretion of HCO3- (K+ out again) 4. Cl- in an apical side i exchange for HCO3- out 5. Cl- does not accumulate in cell = leaves via cystic fibrosis transmembrane conductance regulator (CFTR channel)
170
what types of enzymes are secreted by the pancreas
active or precursors secreted by gland cells at pancreatic end of duct system
171
what does CCK do
stimulates secretion of digestive enzymes potentiates action of secretin = stimulate bicarb secretion from pancreas stimulates contraction of gall bladder/relaxes sphincter of oddi
172
where and why is CCK secreted
produced in small intestine = in response to presence of amino acids/FA in small intestine
173
give 2 examples of active enzymes secreted by pancreas
alpha amylase = starch to maltose | lipase = triglycerides to monoglycerides and FA
174
give 3 examples of enzymes precursors secreted by pancreas
zymogen = trypsinogen to trypsin = mediated by enterokinsases = trypsin activates other enzymes = chymotrypsin
175
what is somatostatin
produced in D cells of pancreatic islets/islets of langerhans = powerful inhibitor of exocrine secretion
176
what do the isles of langerhans contain
alpha cells beta cells D cells PP cells
177
what do alpha cells produce
glucagon
178
what do beta cells produce
insulin/amylin
179
what do delta/D cells produce
somatostatin
180
what do PP cells produce
pancreatic polypeptide
181
what are the phases of pancreatic secretion
cephalic phase | gastric phase
182
what occurs in the cephalic phase
initiated by sensory experience of eating/smelling food etc | = parasympathetic vagus nerve stimulation of acinar cells
183
what occurs in the gastric phase
initiates by presence of food in stomach | = parasympathetic vagus nerve stimulation of acinar cells
184
what has happened by the end of the cephalic and gastric phases
pancreatic ducts filled with inactive zymogens ready for release with HCO3- via sphincter of Oddi amino acids/FA in duodenum = CCK released = gallbladder contract = sphnicter relax
185
what is the hepatic diverticulum
cellular expansion of the foregut which gives rise to the parenchyma of the liver = appear in middle of 3rd week as outgrowth of endodermal epithelium at distal end of foregut
186
how does the bile duct form embryologically
forms when connection between liver diverticulum and foregut narrows
187
how are the gallbladder and cystic duct formed embryologically
small ventral outgrowth developing from bile duct
188
when does bile production begin
12th week - subside during last 2 months
189
how is the lesser omentum formed
formed due to rotation of liver and stomach
190
where does the pancreas develop from
endodermal lining of duodenum as 2 buds = dorsal/ventral | when duodenum rotates to become C shaped = fuse together
191
how is the main pancreatic duct formed
by union of ventral pancreatic duct with distal part of dorsal bud
192
how are the islets of langerhans formed
develop from pancreas parenchyma at 3rd month
193
describe the histology of sinusoids
thin discontinuous fenestrated epithelium no basement membrane contain scattered kupffer cells but cannot see this on h&e
194
describe the order of vessels that carry bile
canaliculi bile ductules trabecular ducts bile ducts
195
describe the histology of hepatocytes
polyhedral epithelial cells abundant mitochondria = granular cytoplasm large central spherical nuclei may be binucleate
196
what are the 3 layers of the gall bladder wall
1. simple columnar epithelium on bm 2. specialised mucosa of loose fibrous connective tissue 3. thick muscularis propria
197
describe the histology of the pancreas
poorly defined fibrous capsule septa divides glands into acini pacinian corpuscles
198
do liver cells replicate
yes because binucleate cells so regeneration capable
199
what are pacinian corpuscles
onion shaped connective tissue built up around nerve endings = reduce mechanical sensitivity of nerve
200
describe the histology of acinar cells
pyramidal shape rich rER basally zymogen granules apically single nucleus
201
do liver cells replicate
yes because binucleate cells so regeneration capable
202
what are ito cells
in sinusoids fat storing cells play role in FA regeneration
203
what cells produce kupffer cells
circulating macrophages derived from monocytes
204
what is the role of insulin in the liver
liver stores glycogen insulin promotes conversion of excess glucose to glycogen glycogen can be broken down and released as glucose in response to glucagon
205
how is iron stored in the liver
transferrin in hepatocytes | ferritin in kupffer cells
206
what are the consequences of high fatty acid beta-oxidation
too much acetyl CoA produced = too much for Krebs = increased ketogenesis = results in acetone and hydroxybutyrate
207
how is high beta oxidation regulated
high levels of glycerol-3-phosphate indicate high levels beta oxidation = insulin released to inhibit (glucagon stimulates beta oxidation)
208
what 2 ways can ketoacidosis occur
``` diabetic = not enough insulin alcohol = high glucagon ```