The Liver and Excretion Flashcards
1
Define excretion
the reemoval of waste products of metabolism from the body
2
define metabolism
all chemical reactions that happen in the cells
4
what does liver break down?
amino acids
6
what happens to amino acids in the body?
they are either used to make proteins or are broken down or excreted.
3
what are the waste products produced by the cells?
carbon dioxide and nitrogenous waste , most of which are toxic
10
define detoxification
when harmful substances are broken down into less harmful compounds
7
how are amino acids broken down by the liver?
4 steps of the ornuthine cycle
- nitrogen containinf amino groups are removed (deaminiation) from excess amino acids and form ammonia and organic acids
- organic acids are respred to give ATP or converted to carbohdrates to be stored as glycogen.
- ammonia is to toxic for mammals to excrete directly so its combined with co2 in the ornithine cycle and creates urea.
- the urea is released into the blood and the kidneys filter it from the blood to remove it as urine
5
why does the liver break down amino acids?
they contain nitrogen in their amino groups and so cant be stored by the body so an excess is damaging
9
what harmful substance does the liver break down?
alcohol
drugs
unwanted hormones
8
which part of the ornithine cycle occurs in the mitochondria of the liver cells?
ornithine convertion to citruline through ammonia + co2 = carbaroyl phosphate
11
what is alcohol broken down to?
damages cells so broken down to ethanol and then to acetic acid
12
what does excess alcohol cause in the liver?
cirrhosis - cells of the liver die and scar tissue blocks blood flow.
14
which hormone is broken down by the liver
insulin
15
liver converts excess glucose into
glycogen
13
why is paracetamol broken down
excess leads to liver and kidney failure
16
function of hepatic artery?
supplies the liver with oxygenated blood from the heart so the liver had a good supply of oxygen for respiration
17
function of hepatic vein?
takes deoxygenated blood away from the liver
18
function of hepatic portal vein?
brings blood from the duodenum and ileum so its rich in products of digestion so any ingested or harmful substances can be broken down straight away.
19
bile duct function
takes bile to the gall bladder to be stored
20
what is bile
a substance produced by the liver which emulsifies fats
21
what are liver lobules?
cylindirical structures made of cells called hepatocytes that are arranged in rows radiating out from the centre
22
what in the lobule connects to the hepatic vein
central vein
23
what are connected to liver lobules
many brances of the hepatic portal vein, hepatic arteyr and bile ducts.
24
how are hepatic arteries and veins connected to the central vein?
capillaries called sinusoids
blood runs through sinusoids and past hepatocytes, which do what?
remove harmful substances and oxygen from the blood.
26
harmful substances are broken down by
hepeatocytes into less harmful substances which re enter the blood.
27
central veins from all lobules connect to form
the hepatic vein
28
what do kuppfer cells do?
attach to the walls of the sinusoids and remove bacteria and break down old red blood cells.
29
hepatocytes produce?
bile
30
bile is secreted into
bile canalicili whoch drawn into bile ducts and leave the liver
IDENTIFYING LIVER UNDER MICROSCOPE
the large white circular shape is
the central vein
IDENTIFYING LIVER UNDER MICROSCOPE
red dots of cells are
the nuclei of hepatocytes
IDENTIFYING LIVER UNDER MICROSCOPE
many white spaces are
sinusoids
