| Osmoregulation trigger words | Osmoreceptors
ADH release
Receptors (DCT/Collecting duct)
Aquaporins
Osmosis
Blood water potential
Urine |
| What is the Kidney made up of | 1. outer layer called the cortex
2. inner layer called the medulla
3. tubes called of nephrons |
| Ultrafilteration/ bowmans capsule | High blood pressure / hydrostatic pressure;
Caused by LV contraction;
3. Small molecules (glucose, amino acids) can move through the pores of the capillary (but not red blood cells);
4. Small molecules pass through the basement membrane;
Protein too large to go through basement membrane;
Molecules then pass through the podocytes and into the Bowman’s capsule. |
| What is afferent ateriole | blood flows into glomerulus |
| What is Efferent arterioles | blood flows through efferent ateriole out of the glomerulus E FOR EXIT |
| Why does the filterate enter bowmans capsule | due to high blood pressure caused by
contraction of the heart |
| What happens in the Proximal Convoluted Tubule | Selective reabsorption |
| Selective reasorption | Molecules move from the PCT through the epithelial lining the PCT and through the endothelial cells lining the capillaries
ALL the glucose molecules move from PCT and into the blood via facilitated diffusion (from a high to low concentration through carrier/channel proteins) and by active transport (from low to high conc via carrier proteins – this requires energy)
ALL amino acids are reabsorbed in the same way as glucose.
The high conc of glucose and amino acids in the blood cause the water potential in the blood to decrease. So water moves out of the PCT and into blood via osmosis (from a high to low water potential) |
| Loop of Henle | -Na+/Cl-
-move out of the thick ascending limb and into the medulla
-by active transport against the conc gradient (through carrier proteins which requires ATP)
* The high conc of ions in the medulla reduces the water potential in the medulla. This causes water to move out of descending limb
into the medulla . this causes high concentration of Na+/Cl- in bottom of the loop of Henle .
Na+/Cl-
-move out of the thin ascending limb and into the medulla.
-by facilitated diffusion from a high to low concentration.
* This movement causes there to be a lower concentration of ions in the thick ascending limb. |
| What increases blood water potential | -drinking water
- aerobic respiration
- water in food
INCREASES
-sweating
-urination
-diahorrea
DECREASES |
| ADH stand for | Anti Diuretic Hormone |
| When is ADH released | released by the pituitary gland when they is low blood wp |
| OSMOREGULATION THEORY | 1. If the water potential of the blood plasma decreases e.g. dehydration, the osmoreceptors in the hypothalamus are stimulated.
2.. This causes impulses to be sent to the posterior pituitary gland and the hormone ADH is released into the blood. (ADH is transported to the kidneys)
3.ADH binds to receptor proteins in the epithelial cell membrane that line the distal convoluted tubule and the collecting duct.
4. The binding of ADH causes aquaporins (water channel proteins) to be inserted into the membrane. This increases the DCT and collecting duct’s permeability to water.
5. Increased water moves out of the DCT, through the aquaporins and into the capillaries (by osmosis). This raises the blood water potential.
6.As a result a decreased volume of urine is
produced.
7.7. As water is reabsorbed the water potential of the blood returns to normal (negative feedback). |
| Osmoregulation trigger words | Osmoreceptors
ADH release
Receptors (DCT/Collecting duct)
Aquaporins
Osmosis
Blood water potential
Urine |
