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Excretion Revision notes

Excretion ­ The removal of metabolic waste from the body, such as excess, un-useful or toxic products.
Hepatic Vein ­ Takes away deoxygenated blood from the liver to the inferior vena cava.
Hepatic Artery ­ Brings oxygenated blood into the liver.
Hepatic Portal Vein ­ Brings nutrients…

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The liver is the only organ with a second blood supply ­ the hepatic portal vein carries absorbed products of
digestion from the gut.
Oxygenated blood from the heart travels from the Aorta via the Hepatic Artery into the liver. This supplies the
oxygen that is essential for aerobic respiration.…

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Deamination:
Amino acid + oxygen Keto acid + Urea

Ornithine cycle ­ ammonia is combined with CO2 to form urea




The ammonia is very soluble and highly toxic. It must be converted to a less toxic form very quickly. The ammonia is
combined with carbon dioxide to produce urea. This…

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Cirrhosis
Fatty deposits in hepatocyte cells
Normal structure of lobules is lost
Scar/fibrous tissue is laid down
Nodules form
Liver becomes hard and shrunken
Disruption to blood flow ­ blood bypasses sinusoids
Inflammation/Hepatitis
Loss of liver function e.g. deamination doesn't take place, ammonia will accumulate.

Kidney structure
The cortex is…

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Collecting Duct




Composition of fluid is changed by Selective re-absorption
In the PCT the fluid is altered by the reabsorption of all the sugars, most salts and some water.
In total about 85% of fluid is reabsorbed here.
In the descending limb of the loop of Henle, the water potential…

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Water
Amino Acids
Glucose
Urea
Inorganic ions (sodium, chloride and potassium).
In the capillary, blood cells and protein are left. The presence of proteins means that the blood has very low (negative)
water potential. This low water potential ensures that some of the fluid is retained in the blood containing…

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The arrangement of the Loop of Henle is known as a hairpin countercurrent multiplier system. The overall effect of this
arrangement is to increase the efficiency of salt transfer from the ascending limb to the descending limb. This causes a
build-up of salt concentration in the surrounding tissue fluid.
The…

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Kidney failure

Kidney failure is the inability to (i) remove excess water urea and salts and (ii) regulate water and salt levels.
The most common causes are:
diabetes mellitus
hypertension
infection
Injury to the back
It can be treated by dialysis ­ the most common treatment for kidney failure. It…

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antibodies. As a result all the antibodies carrying a blue bead and attached to hCG are held in one place forming a blue
line. There is always one control blue line to use for comparison; a second blue line indicates pregnancy.

Testing for anabolic steroids

Anabolic steroids increase protein synthesis…

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