excretion

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  • Created by: sarah
  • Created on: 02-01-15 15:44
what are the main substances that need to be excreted?
carbon dioxide and urea
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where is CO2 produced?
in every cell as a result of respiration
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were is urea produced?
in liver from excess amino acids
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in what from does carbon dioxide travel in blood?
some binds to haemoglobin to make carboxyhaemoglobin some binds with h20 to make h2co3 (carbonic acid), most is hydrogen carbonate ions (HCO3-)
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how is too much co2 detected?
binds with water (with carbonic anhydrase) (forming carbonic acid) desociated to form hydrogen carbonate ions and H+ ions. these h+ ions lower ph wich is detected in respiritory center in medulla oblongata wich sends signal to increase breathing rate
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what is respiratory acidosis caused by?
blood ph being less than 7.35, asthma, bronchitis, severe pneumonia
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what is the arangement of vessels going into and out of the liver?
.
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what are the properties of hepatocytes?
many microvili, very dense cytoplasm, specialised amount of organells
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what is the function of kupffer cells?
specialised macrophages that recycle old red blood cells and release bilirubin wich forms part of bile
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what are the functions of the liver?
to store vitemin D, A, B12, glycogen, ion. controll lipid blood glucose and amino acid levels, detoxify alcohol and drugs, hormone break down, destroy old rbcs
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what are the two break down stages of amino acids?
deamination and the orthine cycle
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what happens during deamination?
amino acids are broken down into keto acid (used in respiration) and amonia
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what are the stages of the orthine cycle?
co2 combinds with amonia and orthine to make water and citrulline, ammonia is addesd to the citrine to produce arginine and water. water is added to arginine to produce urea and ornithine
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why is ethanol a toxin?
it represses nerve activity
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how is ethanol detoxified?
ethonal dehydrease converts it into ethanal by remoing 2 hydrogen atoms, ethanal dehydrase does the same and converts ethanol into ethanote. this conbines with coenzyme a to form acetyl coenzyme A (wich is used in resiration)
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how does too much ethanol lead to hepatitis?
when it isdetoxified, hydrogen atoms are removed, they reduce NAD. this means the NAD can not be used to break down fatty acids causing fatty liver wich can lead to hepatitis
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what is the role of the kidney?
remove waste products from blood and produce urine
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what is the basement membrane made of?
collagen and glycoproteins
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what is filtered out of the blood at the bowman's capsule?
water, amino acids, glucose, urea, sodium calcium and potasium ions
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what is the order of tubes in a nephron?
proximal convulated tubule, loop of henle, distal convoluted tubule, collecting duct
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how does sodium ions get reabsorbed in the proximal convilated tubule?
cotransporters help it to enter cells lining tubules via facilitated diffusion, it is then activly transported out of the cell on the other side and diffuses into capilleries
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wich parts of nephron does water reabsorbtion not ocur?
the ascending limb
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how is water lost from our bodies?
breathing, sweat, urination and defication
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what does urine contain?
water, urea, excess vitemins, hormones
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how is the nephron of some animals adapted to reduce water loss?
more aquaporins in collecting duct, longer loop of henle, very low water potential in medulla
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how is dehydrated blood detected?
osmoreceptors in hypothalamus loose water and shrink stimulating neurosencretory cells to release ADH
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how does body react to dehydration?
the prosterior piturity gland realeses ADH wich travels to kidney and binds with receptors on colecting duct cells, causing more aquaporins to be inserted into membrane
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what is the half life of ADH?
20 mins
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what does ADH stand for?
antidiuretic hormone
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what causes kidney failure?
infection, hypertentin (fdamages capillery walls larger molecules get through), diabetes
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what are the consequences of kidney failure?
death, waste products accumulating (vomiting), fluid accumualates causing swelling, aneamia, unbalance of ions
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what is the role of heparin pump in dialysis machine
avoid blood clots
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what is the advantage of kidney transplant over dyalis?
less expensive in long run, more convienient, dont feel unwell, less restricted diet
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what hormone do pregnancy test test for?
hCG
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how do pregnancy tests work?
.
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what is the half life of anabolic steroids?
16hrs
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what do anabolic steroids do?
increase protein synthesis, build up of tissue
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how are anabolic steroids detected
gas chromatogrophy
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what do the lungs help to excrete?
CO2 and water
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what does the skin help to excrete
water, CO2, hormones, salts and ions and a small amount of urea in sweat
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what does the gut help to excrete?
bile pigments in faeces – also loses water, salts and CO2
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where and how is bile made?
break down of heamoglobin in the liver and it then travels to the gall bladder viar the bile duct and then enters gut
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Why is ammonia converted to urea for excretion despite the fact that there is a high energy cost in doing so?
urea is less toxic than ammonia but still soluble enough to be transported in body fluids some aquatic organisms (not aquatic mammals) can excrete it because it is diluted in the environment
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what is the gross structure of the liver
made up of several lobes and is surrounded by a two layered supportive capsule contains a large store of blood, gall bladder is tucked behind liver
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Other cards in this set

Card 2

Front

where is CO2 produced?

Back

in every cell as a result of respiration

Card 3

Front

were is urea produced?

Back

Preview of the front of card 3

Card 4

Front

in what from does carbon dioxide travel in blood?

Back

Preview of the front of card 4

Card 5

Front

how is too much co2 detected?

Back

Preview of the front of card 5
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