D3 liver Flashcards
what is the observable consequence of jaundice
skin and whites of eyes are tinged yellow
immediate cause of jaundice (short)
bile pigment bilirubin
what is the bile pigment that causes jaundice called
bilirubin
how is bilirubin formed
formed in the liver from the heme grp from break down of haemoglobin
3 possible causes of jaundice
blocked bile duct
increased rbc production
damage/disease of liver
why is temporary jaundice observed in newborn babes 3
- foetal haemoglobin diff from after birth
- rapid breakdown of haemoglobin
- more bilirubin than can be broken down
what is cirrhosis
when damaged liver tissue is replaced with scar tissue
causes of cirrhosis
excessive alcohol/drug intake
chronic hep B/C, chronic bile duct blockage, cystic fibrosis
symptoms of cirrhosis
weakness, fatigue, jaundice
how is cirrhosis identified and cured
id: liver biopsy – scar tissue obserevd
cure: none!
structure of liver (general)
triangular organ with 4 lobes
how many lobules is in a liver lobe
has around 100k lobules
structure of lobules
- central venule from hepatic vein
- six more venules from hepatic PORTAL vein + six arterioles from hepatic artery
- blood vessels connected via sinusoids
what are sinusoids? 2
- blood-filled channels
- formed from subdivisions of hepatic portal vein
what happens in sinusoids 3
- arterial blood mixes with hepatic portal vein blood
- blood comes in contact with liver cells = proteins enter/leave
- sinusoids merge with venules leaving liver = hepatic vein –> carries blood away to vena cava
structure of sinusoids
tubes like capillaries but with DISCONTINUOUS ENDOTHELIUM
capillary vs sinusoid structure 5
capillary // sinusoid
narrower // wider
very small pores // fenestrated (big ass holes)
continuous basement membrane // discontinuous
cylindrical shape // no definite shape
how sinusoids differ from capillaries
- wider
- no walls separating blood from liver cells
- blood and liver cells in direct contact
- phagocytic cells line sinusoids
where is the bile channel
- between 2 rows of liver cells
- isolated from blood supply
what does the bile channel do
- bile from liver flows thru these
- channels merge into ducts – bile carried to gall bladder
what do hepatocytes do?
perform most liver functions (Esp storage and metabolism)
size of hepatocytes?
LARGE
(25 um)
um to cm conversion?
10k um = 1 cm
how many % of the liver is made of hepatocytes
around 80%
when hepatocytes are exposed to teoxic substances, they can ?
regenerate
neurons vs hepatocytes DEATH
neurons dont regenerate while hepatocytes do
what are hepatocytes rich in 5
- mitochondria
- golgi apparatus
- RER + ribosomes
- glycogen granules
- lipid droplets
where are plasma proteins synthesized in hepatocytes 2
RER and golgi complexes
what does the smooth ER do in hepatocytes
degradation of toxins
how do hepatocytes have a exocrine function
secretion of bile
4 examples of plasma proteins synthesized in hepatocytes
globulins, albumin, prothrombin, fibrinogen
3 process of protein syntehsis in hepatocytes
- proteins formed on ribosomes – RER
- sent to golgi apparatus – packaged in vesicles
- vesicles discharged across plasma membrane via exocytosis
what happens to excess amino acids
deaminated in the liver
process of deamination (very chem) 3
- organic part of AA removed and respired/conv to fat/carbs
- amine grp converted to ammonia
- ammonia + co2 = urea
what are Kupffer cells
white blood cells (macrophages) that break down rbcs
where does blood get to the liver from
hepatic artery – brings o2 rich blood
hepatic portal vein – carries most blood to liver – from stomach and SI (cont nutrients, digested food)
where does blood leave the liver
hepatic vein – carries deo2 blood away
why does the liver have a DUAL BLOOD SUPPLY
receives oxygenated blood from hepatic artery
AND
deoxygenated blood from hepatic portal vein
= mixed = cells never get fully o2 blood
the liver _______ nutrient levels
regulates
what nutrients does the liver regulate the levels of 3
- glucose
- amino acids
- short chain fatty acids
(some nutrients in excess can be stored in liver)
what is the normal level of blood glucose in humans + range of variation
90 mg / 100 cm3
70mg – 150mg
how does the liver regulate glucose in the blood
- in sinusoids: glucose drawn and used in metabolism or stored as glycogen
- conversion back and forth controlled by insulin and glucagon
3 how are fatty acid levels regulated in the liver
- fatty acids + glycerol combined into triglycerides
- trigly + proteins (in liver) = stored
- OR transported in blood plasma (as LDLs – low density lipoproteins) to tissues – can be immediately broken down and respired
how does the liver carry out detox (short)
liver acts on drugs and toxins in bloodstream, converting them to less harmful forms for excretion by the kidneys
3 detoxification but the chem explanation
- alcohol oxidised to acetaldehyde (alcohol dehydrogenase)
- acetaldehyde -oxidised-> acetic acid (acetaldehyde dehydrogenase)
- acetic acid –oxidised–> co2 + h2o
what nutrients can the liver store 4
- iron
- carbs (glycogen)
- fats
- vitamins
liver cells break down ______ ____ blood cells
redundant red
where are rbcs formed and how long do they function
bone marrow
120 days – limited time
whats the process of the breakdown of rbcs in the liver 6
worn out cells taken up via phagocytosis by macrophage cells
- globin (protein) and heme split apart
- globin hydrolysed by proteases –> amino acids
- heme breakdown = iron 3 ions
- iron 3 ions removed and attached to carrier protein
- iron stored in liver cells, eventually transported to bone marrow (reuse)
where does the breakdown of rbc occur
kupffer cells
what else is the heme part of haemoglobin converted to besides iron3
bile pigments (into bile channels)
why is HDL cholesterol considered good
it removes LDL from blood by transporting it to liver
what is surplus cholesterol converted into
bile salts
what does bile do
breaks down/emulsifies fats into fatty acids and glycerol
