Have you read the previous post regarding the topic of osmoregulation in I/GCSE Biology? In this post, we'll keep on talking about it!
Kidneys
- The KIDNEYS play a vital role in balancing levels of water, waste and other chemicals in the blood.
- The brain monitors water content constantly and causes the kidney to adjust the concentration and volume of urine produced-
- When the water level of our BLOOD PLASMA is LOW, more water is reabsorbed back into the blood and the urine becomes more CONCENTRATED
- When the water level of our BLOOD PLASMA is HIGH, less water is reabsorbed back into the blood and the urine becomes more DILUTE
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/969896_142496.png)
Factors affecting the amount of water being reabsorbed
In I/GCSE Biology, it's important to study the following factors!
The amount of water that needs to be reabsorbed depends on a number of factors:
- External temperature
- High → Concentrated urine
- Low → Dilute urine
- Level of exercise
- High → Concentrated urine
- Low → Dilute urine
- Fluid intake
- High → Dilute urine
- Low → Concentrated urine
- Salt intake
- High → Dilute urine
- Low → Concentrated urine
ADH
In I/GCSE Biology, ADH is commonly asked in the exam!
The concentration of urine is controlled by a hormone called ADH, which is released into the bloodstream by the PITUITARY GLAND.
When the level of water in the blood is too low, ...
- When the level of water in the blood is too low,
- ADH is released and this causes concentrated urine to be produced.
- This is because the hormone causes the kidney to make MORE PERMEABLE, allowing water to be reabsorbed.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/630875_563247.png)
When the level of water in the blood is too high, ...
- When the level of water in the blood is too high,
- ADH is NOT released.
- The kidney becomes LESS PERMEABLE and this causes dilute, watery urine to be produced.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/621874_893300.png)
In I/GCSE Biology, you should know that the osmoregulation is a kind of negative feedback responses!
Effects of Alcohol on water balance:
- Alcohol causes the kidneys to produce a greater volume of more dilute urine. This can lead to DEHYDRATION
- This is because alcohol suppresses (restrains) ADH production
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/744739_545495.png)
Effect of Ecstasy on water balance:
- Ecstasy causes the kidneys to produce smaller volume of less dilute urine. This can result in the body having TOO MUCH water
- Ecstasy increases ADH production which means the kidneys reabsorb water
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/285202_144938.png)
And we're done with this topic! Well Done!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/766681_97747.png)
Drafted by Alyssa (Biology)
References:
- "What Is Osmoregulation?", https://cdn1.byjus.com/wp-content/uploads/2016/07/47.png
- "Kidney 1". Photo from the internet.
"Kidney 2". Photo from the internet.
- "Water Balance", https://swh-826d.kxcdn.com/wp-content/uploads/2011/01/Renin-angiotensin-aldosterone_system.png
- "Ecstasy", https://ichef.bbci.co.uk/news/466/mcs/media/images/54134000/jpg/_54134329_008148651-1.jpg