5.1.2 (b) the Liver Flashcards

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1
Q

what are the 3 vessels connected to the liver?

A

hepatic artery
hepatic vein
hepatic portal vein

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2
Q

which vessel removes blood from the liver?

A

hepatic vein

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3
Q

which vessels bring blood to the liver?

A

hepatic artery and hepatic portal vein

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4
Q

what is the composition of the blood in the hepatic artery?

A

this is oxygenated blood from the heart

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5
Q

what is the composition of the blood in the hepatic portal vein?

A

this is blood containing high concentrations of nutrients from the intestines to allow for metabolic activity in the liver

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6
Q

what cells make up the liver?

A

hepatocytes

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7
Q

what are the features of a hepatocyte?

A

they have a large nucleus
they have a prominent golgi complex
they have LOTS of mitochondria

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8
Q

why do hepatocytes have a lot of mitochondria?

A

they are very metabolically active cells

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9
Q

why do hepatocytes have a prominent golgi?

A

they have to secrete lots of vesicles of bile

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10
Q

what do hepatocytes do?

A

break down harmful substances in the blood
break down red blood cells into bile

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11
Q

where is the blood from the hepatic artery and hepatic portal vein mixed in the liver?

A

spaces called sinusoids are surrounded by hepatocytes

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12
Q

why is the blood mixed in the liver?

A

this increases the oxygen content of the blood

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13
Q

what are Kuppfer cells?

A

they are found on hepatocytes and ingest pathogens and protect the liver from disease

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14
Q

where does the bile secreted from the hepatocytes go to?

A

the Canaliculus which drains the bile into the bile ductiles and then into the gall bladder

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15
Q

micrograph of a liver tissue

A
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16
Q

what are the main functions of the liver?

A

carbohydrate metabolism
deamination of amino acids
detoxification

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17
Q

how does the liver react to insulin?

A

when insulin levels rise due to a high blood glucose level, hepatocytes are stimulated to convert glucose into glycogen

GLYCOGENESIS

so the liver is a good store of glycogen

18
Q

how does the liver react to glucagon?

A

when glucagon levels rise due to a low blood glucose level, hepatocytes are stimulated to convert glycogen into glucose

GLYCOGENOLYSIS

19
Q

what is transamination?

A

the conversion of one amino acid into another

20
Q

why is transamination important?

A

allows diet to be balanced with different amino acids

21
Q

what is deamination?

A

the removal of an amine group from a molecule

22
Q

why must proteins and amino acids be deaminated?

A

proteins and amino acids cannot be stored in the body

23
Q

what do hepatocytes produce as a waste product of deamination?

A

they convert the amino group into ammonia and then into urea

24
Q

why can’t ammonia just be excreted instead of converting it to urea?

A

ammonia is too toxic to be excreted directly by mammals

25
Q

what happens to urea produced in deamination?

A

transported and excreted by the kidneys

26
Q

what happens to the rest of the amino acid?

A

it is used in cellular respiration or converted into lipids for storage

27
Q

what cycle converts ammonia into urea?

A

the ornithine cycle

28
Q

ammonia and carbon dioxide and ornithine

A

citruline and water

29
Q

citruline and ammonia

A

arginine and water

30
Q

arginine and water

A

urea and ornithine

31
Q

generalisation of ornithine cycle

A

ammonia + carbon dioxide
forms
urea + water

32
Q

what is detoxification?

A

when toxic substances are made harmless

33
Q

what two substances can the liver detoxify?

A

hydrogen peroxide
ethanol

34
Q

what enzyme do hepatocytes contain to break down hydrogen peroxide?

A

catalase

35
Q

what does catalase split hydrogen peroxide into?

A

oxygen and water

36
Q

what enzyme do hepatocytes contain to detoxify ethanol?

A

alcohol dehydrogenase

37
Q

what is ethanol broken down into?

A

ethanal and then to ethanoate

38
Q

why is it important to detoxify ethanol?

A

excess ethanol can lead to cirrhosis of the liver
liver cells end up dying

39
Q

what is wider the hepatic portal vein or hepatic artery?

A

hepatic portal vein

40
Q

which is branched hepatic portal vein or hepatic artery?

A

hepatic portal vein

41
Q

how are hormones excreted from the body?

A

hepatocytes remove the NH2 group (deamination)
converts into ammonia
ammonia enters ornthine cycle and urea is formed
urea leaves via the kidney