2.75 Urine

• urine conatins: salts, water, urea
• salt and water affects the composition of tissue fluid called osmoregulation
• the removal of urea is part of the process of the excretion of metabolic waste.
• the composition of urine varies on the conditions in which a person is operating

2.74 ADH

• ADH - Anti-dirretic hormone
• it is produced in the hypothalamus region of the brain
• it flows through the blood as the kidney as it's target
• ADH has the ability to make the blood more or less concentrated
• ADH targets the collecting duct, and makes it possible for more water to be absorbed through the collecting duct (2.72)
• it makes the walls more pours, allowing more water to pass
• the consequence of this would be that the urine would have a smaller volume and a higher concentration

How does ADH react with:
a hot day -


a cold day -



dehydration -

2.73 glucose reabsorbtion

• selective reabsorbtion - the molecule is selected (glucose) and put back into the blood
• filtration occurs in bowman's capsule
• Gluscose was one of the filtrates taken out of the blood.
• Urine does not usually contain glucose (urine containing glucose is usually diagnosed as diabetes)
• But the reason why glucose is present in the urine after being filtrated out of the blood is because in the proximal convoluted tubule section glucose is removed and taken back into blood
• so glucose is reabsorbed into the blood in the PCT

2.71 Ultrafiltration

• The nephron carries of the filtration of blood which results in filtered blood (clean) as well as waste represented by urine.
•The urine will emerge from the end of the Medulla and carry on into the pelvic region.
• urine contains water, salts and (urea)
• The filtration begins in the bowman's capsule.
• First the blood arrives in the kidneys through the afferent arteriole with HIGH pressure.
• It continues into a twisted part in the arteriole called the glomerulus (inside the capsule)
• Then the blood exits the capsule out of a smaller arteriole than the Afferent called the Efferent
• The blood pressure increases in the glomerulus
• The high pressure forces plasma (water, salts, amino acids, glucose and urea) out inside the blood.
• These are forced into the inside of the bowman's capsule
• When the plasma is forced into the capsule we change the name of it to glomerula filtrate
• so the blood has been filtered by pressure due to the smaller blood vessel generating a high pressure forcing the liquid into the tube

2.70 nephron structure

• The Aorta has blood taken into the kidney through the the renal artery
• the kidney filters the blood and the urine (as waste) goes down the ureter to the bladder for storage
• The filtered blood exits through the Renal vein to the Vena Cava

structure of kidney:
- cortex is the outer region (light brown)
- Medulla is the inner region (dark brown)
- pelvic region is the space, from where the urine moves into the ureter

the reason behind the different colours is because the kidney is made up of millions of tubes (Nephrons)
• the tube starts on the edge of the medulla and moves out into the cortex, where it has a little twisting section (convoluted tubules), then dipping back down into the medulla (the dip is known as a loop of Henle)and repeating until coming to a dead end.
• the dead end is known as a bowman's capsule
• The tight knot of blood vessels inside the capsule is known as a glomerubus
• The first convoluted tubule after the capsule is known as the proximal.
• the second is known as a distal (dct)
• The nephron structure gives the different colours to the kidney