1. Urinary system with some IGCSE questions
EXCRETION
Urinary system
with some IGCSE questions

2. Homeostasis.
Homeostasis is the general function that controls and keeps constant the conditions of our body.

3. Substances include carbon dioxide, urea and salts
Excretion
it is the removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements.
Substances include carbon dioxide, urea and salts

4. Urinary system anatomy

5. the kidneys, liver, lungs, and skin.
Excretory systems regulate the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients. Components of this system in vertebrates include:
the kidneys, liver, lungs, and skin.

6. Outline structure of a kidney

7. The kidney
renal cortex
pyramids
renal pelvis
renal medulla
ureter

8. Kidney function
Removal of urea and excess water and the reabsorption of glucose and some salts, so:
Remove wastes.
Regulate water levels

9. The nephron

10. X section to nephron

11. Nephron

12. Nephron function
role of renal capsule - filtration from blood of water, glucose, urea and salts
role of tubule - reabsorption of glucose,most of the water and some salts back into the blood, leading to concentration of urea in the urine as well as loss of excess water and salts

13. How can our body keep the percentage of water in our body around 60/70%?
60 – 70 % of the weight of our body is water (around 40 l of water).
If it is very hot and we sweat, we lose some of our body water composition.
If we lose water, we can suffer dangerous dehydration
We have to” save” water and we must not lose more water through urine.
The urine will be more concentrated (water is reabsorbed)
If we drink a lot of water, we have an extra supply of water (that we don’t need).
Our urine will be more diluted (water will not be reabsorbed in kidneys).

14. Urea
Urea is formed in the liver from excess amino acids most of the water and some salts back

15. How toxic waste from cellular respiration (catabolism) is excreted
1- Blood + waste come to kidneys by renal artery.
2-Filtration of waste in the nephron.
3-Reabsorption of some useful products that could have been filtered, to the capillaries surrounding the nephron.
4-Waste is concentrating as urine.
5-Urine goes to the
-collecting duct
- ureter
- bladder
- and goes out by urethra

16. Kidney stones (renal calculi)
It is the term commonly used to refer to stones, or calculi, in the urinary system. Stones form in the kidneys and may be found anywhere in the urinary system. They vary in size. Some stones cause great pain while others cause very little. The aim of treatment is to remove the stones, prevent infection, and prevent recurrence. Both nonsurgical and surgical treatments are used. Kidney stones affect men more often than women.

17. Kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine.

19. Renal (kidney) failure
It results when the kidneys are not able to regulate water and chemicals in the body or remove waste products from your blood. Acute renal failure (ARF) is the sudden onset of kidney failure. This condition can be caused by an accident that injures the kidneys, loss of a lot of blood, or some drugs or poisons. ARF may lead to permanent loss of kidney function. But if the kidneys are not seriously damaged, they may recover. Chronic kidney disease (CKD) is the gradual reduction of kidney function that may lead to permanent kidney failure, or end-stage renal disease (ESRD). You may go several years without knowing you have CKD.

20. Dialysis
Artificial maintenance of glucose and protein concentration in blood and diffusion of urea from blood to dialysis fluid.

21. In case of chronic renal failure…
What about a kidney transplant?

23. http://lifeblood. anaemiaworld

24. discuss the advantages and disadvantages of kidney transplants, compared with dialysis
Advantages: Dialysis takes a HUGE amount of time, and your life revolves around it. You also risk infection. A kidney transplant is permanent
Disadvantages: Obviously, the risks associated with any surgery, risk of rejection by your body, and you have to take anti-rejection drugs your whole life.
IGCSE – syllabus question

25. Some IGCSE questions Sandra Brinkhoff
Sandra Brinkhoff

29. Some concepts taken from IGCSE Biology syllabus 2010

30. http://www. emc. maricopa. edu/faculty/farabee/BIOBK/BioBookEXCRET