2.75 Urine

Urine contains:
-Salts (Affects the composition of the tissue fluids = osmoregulation)
-Water (same as salts)
-Urea (Part of excretion of metabolic waste)

2.74 ADH - Anti Diuretic Hormne

-This hormone is produced in a region of the brain called the Hypothalamus
-Like all hormones it flows through the blood streams and its target is the kidney
-The effect of ADH is to control and alter the quantity of water in blood
-The tissue fluid is isotonic with the cytoplasm of the cell (role of ADH)
- ADH actually targets collecting ducts
-ADH allows more water to go out of the collecting duct
-ADH makes the collecting duct walls more porous (more water can escape)
-The water goes back into the blood
-The consequence is that the urine is more concentrated and it has a lower volume.

Extension:
Hot day = more ADH (sweat)
Cold day = less ADH (not as much sweat)
Dehydrated= more ADH (body needs more water for it to work)

2.73 Glucose re-absorbtion

-Glucose is selected to be put back into the blood
-Filtration happens in the bowman's capsule
-Urine does not contain glucose
-If there is glucose in the urine, the person might be suffering from diabetes
-In the first tubule (PCT) glucose is removed and put back into the blood

2.72 Water re-absorbtion

-When ultrafiltration happens there is too much water is filtered
-Water is removed from the filrate when it passes through the collecting duct
-Then it is returned back to blood vessels
-it goes back into the blood stream.
-The water has been selected and has been reabsorbed into the blood
-This is called "selective re-absorption" (of water)

2.71 Ultrafiltration

The filtration of the blood happens in the nephron
The filtration makes 2 products:
-Clean blood
-Waste/Urine
urine= water&salts&urea

-The filtration process begins in the Bowman's Capsule
-The filtration of blood begins when the blood comes in (high pressure) from the afferent arteriole into the kidney
-The blood vessel starts too branch off in a twisted and coil structure know as the glomerulus.
-The diameter of the Efferent arteriole is a lot smaller than the Afferent arteriole.
-This leads to high preassure
-The plasma (Water, salts, amino acids, glucose & urea) is forced out of the blood vessel and into Bowman's Capsule
-This is called glomerular filtrate

2.70 Nephron Structure