Osmoregulation And The Kidneys Flashcards
What is osmoregulation?
Regulating the water content in the body
What would happen to body cells if water content is too HIGH?
- Water moves in by osmosis
- Cells May burst (no rigid cell structure like plant cells)
What would happen to the body cells if water concentration in the blood was too LOW?
- Water moves out of the cell by osmosis
- Causes cells to shrink
What are the three roles of the kidneys?
1) Removal of urea from the body. Urea is produced in the liver, from the breakdown of excess amino acids
2) Adjustment of ion levels in the blood
3) Adjustment if water content of the blood
The glomerulus
- What process happens here?
- How does this happen?
- Why does it happen?
- Filtration of blood
- Blood is squeezed through, allowing glucose, urea and water through. Protein and blood cells are too big to fit through.
- Separates unwanted substances from the blood
The first convoluted tubule (proximal)
- What process happens here?
- How does this happen?
- Why does it happen?
- Selective reabsorption/active transport
- Glucose and Mineral Ions are absorbed by active transport
- The glomerulus filtered too many substances and they are resbsorbed into the blood to be used in the body
The Loop Of Henle
- What process happens here?
- How does it happen?
- Why does it happen?
- Osmosis
- By reabsorbing water into the blood to create concentrated urine
- The concentration of water is higher in the Loop Of Henle than the blood
The collecting duct
- What process happens here?
- How does it happen?
- Why does it happen?
- Osmosis - Water is reabsorbed
- The Hormone ADH controls it
- More, excess water is absorbed from the Loop of Henle, needed for the body to survive
What happens if water in the blood is too low?
- Pituitary gland secretes ADH
- Collecting duct becomes more permeable to water
- Water passes back into the blood
What does ADH stand for?
Anti-Diuretic Hormone
What happens when water in the blood is too high?
- The release of ADH is stopped
- The collecting duct becomes IMPERMEABLE TO WATER
- Water passes through the collecting duct to the ureter
What happens the water concentration if the concentration of sodium ions in the blood is high?
Water concentration falls.
Why is dialysis used?
For kidney failure, to filter the blood in a person’s body
Describe the dialysis membrane
Partially permeable
Permits substances like ions and waste products but not big molecules like protein
How do the following move in dialysis:
- salt in the blood
- urea
- sugars and substances needed by the body
- Salt moves out of the blood by DIFFUSION
- Urea moves out of the blood by DIFFUSION
- Sugar and other substances needed by the body do not move
