5.1.2 Liver and Excretion Flashcards

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1
Q

Deamination

A

Amino Acid + Oxygen ->keto acid + ammonia
Keto Acid enters respiration to release energy
Ammonia enters the ornithine cycle to be converted into urea

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2
Q

Examples of Excretion

A

CO2: waste from respiration, excreted via the lungs
Nitrogenous Waste: urea, produced in the liver and excreted as urine via the kidneys
Bile Pigments: produced from the breakdown of haemoglobin in the liver and excreted as bile in the intestines (faeces)

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3
Q

Hepatic Artery

A

supplies liver with oxygenated blood from the heart

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4
Q

Hepatic Vein

A

Takes deoxygenated blood away from the liver

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5
Q

Hepatic Portal Vein

A

brings blood from the duodenum and ileum so that toxins can be filtered out and broken down here in the liver

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6
Q

Bile duct

A

takes bile produced by the liver to the gall bladder to be stored

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7
Q

carbohydrate metabolism

A

Hepatocytes are involved in the homeostatic control of glucose levels in the blood. When the blood glucose levels rise, insulin levels rise and stimulate hepatocytes to convert glucose into glycogen.

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8
Q

Detoxification

A

Level of toxins tend to increase. Apart from urea, many other metabolic pathways produce potentially poisonous substances. The liver is where most of these are detoxified.

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9
Q

Transamination

A

The conversion of one amino acid into another. This is important because the diet does not always contain the required balance of amino acids but transamination can resolve this issue

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10
Q

Excretion in kidneys

A

Blood enters kidney through renal artery and then passes through capillaries in cortex. When in capillaries, substances are filtered out of blood into tubules called ultrafiltration. Useful substances reabsorbed back into the blood called selective reabsorption. Remaining substances such as urea pass along tubules then along the ureter to the bladder to be expelled during urination. Filtered blood passed out of the kidney through the renal vein.

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11
Q

Selective Reabsorption

A

Occurs throughout the nephron after the renal capsule. When filtrate is first formed, it is hypotonic to the blood.

Most of this occurs in the PCT, cells lining tubule are adapted for the reabsorption of substances from the lumen, across them, into the blood capillaries around them.

85% reabsorbed

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12
Q

Causes of Kidney Failure

A

Diabetes
Hypertension
Genetics
Kidney stones

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13
Q

Main Problems with Kidney Failure

A
blood in urine
proteins in urine 
selective reabsorption may stop 
urea and toxins may accumulate in the blood 
disrupted water/ion balance
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14
Q

Glomerular Filtration Rate (GFR)

A

Rate that substances are filtered out of the blood in the glomerulus into the renal capsule

below normal rate = kidneys not functioning

blood test measures conc of creatinine (a breakdown product from muscle cells)

Age, Gender and Fitness need to be taken into consideration

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15
Q

GFR readings

A

reading below 60 for 3+ months indicated severe chronic kidney disease

reading below 15 shows kidney failure

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16
Q

Haemodialysis

A

Patients blood is passed through a dialysis machine — blood flows in one side of the partially permeable membrane and dialysis fluid flows on the other side

Waste products diffuse into fluid, removing them from the blood. Larger molecules can’t pass.

Each session takes 3-5 hours and need 2-3 sessions weekly in hospital

patients feel unwell between sessions as waste products build up

17
Q

Peritoneal Dialysis

A

Dialysis fluid is put through a tube that passed from outside the abdomen into their abdomen cavity. Waste products diffuse out into fluid across the peritoneum.

Fluid then drained out through tube

can be carried out at home either several times a day or one long overnight session

risk of infection around site of tube and patient doesn’t have dialysis free days.

18
Q

Kidney Transplant

A

new kidney implanted to replace damaged kidney

doner must have same blood and tissue type. often donated from living relatives but can receive one from an organ doner.

advantage; cheaper, more convenient, can live fairly normal life

disadvantage; major surgery with risk of infection, risk of rejection, will have to take immunosuppressants so more at risk to illness

19
Q

pregnancy tests

A

hCG molecules carried up test in urine and bind to mobile antibodies to form hCG/antibody complex

complex bunds to immobilised antibodies to form a coloured line of woman is pregnant

mobile antibodies within hCG move up to second window

excess mobile antibodies bind to immobilised antibodies to form a line whether pregnant or not

20
Q

pregnancy test

A

A coloured line only occurs at the bottom window if woman is pregnant (requires presence of hCG)

A coloured line will spread in the top window either way — this is a control window to ensure test is working

21
Q

recreational drugs

A

drugs such as cannabis, ecstasy or cocaine will be present in the urine

test strips containing antibodies that the drug will bind to

a sample of urine is applied to test strip and if present a colour change is i’ll occur indicating a positive result

if positive, urine sample is sent for further testing to confirm which drugs are used. second test uses GC/MS

22
Q

Anabolic steroids

A

Drugs that build up muscle tissue that can cause liver damage.

Tested using Gas Chromatography/ Mass Spectrometry (GC/MS)

In GC, urine sample is vaporised and passed through a column containing a polymer. Different substances move through as different speeds to separate out.

Once separated, MS converts them into ions then separated via mass and charge

Results analysed by computer by comparing results of known substances to detect what was in the urine sample

23
Q

Osmoregulation

A

controlling the amount of water and salts in the body

24
Q

Increased Water Potential

A

Red Blood Cells become hypotonic and water enters the cell and it will eventually burst.

Water enters cell via diffusion (high to low conc)

Kills cells and reduces amount of red blood cells in the body

25
Q

Decreased Water Potential

A

Red Blood Cells become hypertonic and shrink

Water leaves cells via diffusion (high to low conc) and enters the vessel

reduces oxygen carrying capacity and function

26
Q

Ways water is lost

A

urine
faeces
breathing
sweating

27
Q

ultrafiltration

A

Produces filtrate— some of this is reabsorbed (water, proteins, glucose) and some is excreted (urea, some mineral ions)