2.75 - Urine

- Role of brain influencing the kidneys
- Filtration of blood in the kidneys
- Resulting in the waste going into the bladder and coming out as urine

Urine contains: Salt, H2O and Urea
Salt and H2O affected by the composition of the tissue fluid called Osmoregulation.
The Removal of urea - part of the process of excretion of metabolic waste as the fluid beings to leave.

The composition of Urine varies - depends on the condition of which the person is operating.

2.74 - ADH

ADH - Anti Diuretic Hormone
Produced in the Hypothalamus (a part in the brain) - flows through the blood stream to it's target (the kidney)
ADH - controls and alters the composition of water in blood
Tissue is isotonic with the cytoplasm of the cell
ADH - targets the collecting duct (more accurate then kidney)
- It allows more water to come out of the collecting duct

- Collecting Duct: Where water is selectively reabsorbed into the blood
- this water goes back into the blood
- consequence of ADH secretion - Urine coming out will be more concentrated and will have a lower volume

- ADH response to a hot day
- ADH response to a cold day
- ADH response to dehydration

2.73 - Glucose re-absorption

Selective re-absorbtion means the molecule is selected and re-absorbtion means it will go from the glomereule filtrate back into the blood

- filtration occurs in Bowmans capsule - contains glucose in the plasma, along with H2O, Salt and urea.
- end of nephron is where the Urine comes out
- If you have glucose in your urine - it means you have diabetes either high or low deficiency.

- Proximal Convoluted Tubule - glucose is removed and taken back into the blood

2.72 - Water re-absorption

- In the Bowmans capsule - Ultrafiltration takes place
- When filtration occurs, it filters out too much water
- As filtrate passes along the tube and reaches Collecting Duct
- As it passes through the Collecting Duct - water is removes from the filtrate.
- It goes back into the blood stream

- Water has been selected and reabsorbed into the blood - Selected reabsorption

2.71 - Ultrafiltration

- Nephron of the kidney (shown) - carries out filtration of blood
two things : Filtered blood (clean blood) and waste blood, Urine

- Urine emerges from bottom of tubule, goes into pelvic region.
Bowman's capsule - where filtration begins - Ultrafiltration

Filtration begins when blood comes in the Afferent arteriole the high pressure makes it wide.
- starts to branch into twists and coils - Glomerulus
- Blood vessel coming out, develops high pressure
- High pressure forces the liquid in blood (Plasma) out of the blood vessel into the inside of the Bowmans capsule

Blood has been filtered by pressure due to the smaller diameter arteriole, generating a high pressure in the glomerulus, forcing the liquid into the tube

2.70 - Nephron Structure

- Branch of Aorta taking blood into the kidney is called the Renal Artery
- Kidney filters the blood
- Contents which are removed are called Urine (through Ureter) - collects in Bladder
- Filtered blood goes through the Renal Vein

Out region - Cortex
Inner region - Medulla
The Space where the urine collects and drains down the ureter

Tube starts on the edge of the medulla and goes out into the cortex, then winds and then drops down to the medulla again, then winds and comes to a dead end.
The dead end is called the Bowman's capsule.
The tube structure is called a Nephron

- IN DIAGRAM - Cortex
- IN DIAGRAM - Medulla
- Twisted sections - Convoluted tubules
- The dip - loop of Henlé
- Dead end cup shape structure - Bowman's Capsule
- Tight knot of blood vessels - Glomeruloui
- First twisted section - Proximal convoluted tubules (PCT)
- Second twisted section - Distal convoluted tubules (DCT)