Bio 10 - Excretion in Humans - IGCSE BIOLOGY.pptx

IGCSE Biology used

1. Excretion in Humans Biology IGCSE Grade 10 Misbahul Munir, S.Si.

2. Learning Objective Describe the role of liver in the assimilation of amino acids, the lung as the excrete carbon dioxide, the kedneys to excrete urea, excess water, and salts, and the kidney tubule, including the role of the glomerulus in the filtartion and the role of the tubule in the reabsorption.

3. Outlines Excretion in humans The kidney The role of the liver in excretion Urine test

4. Excretory organs

5. Substances that needs to be removed

6. The kidneys

7. Water balance and osmoregulation

8. The structure of the Kidney Go to this Jamboard to complete the worksheet together

9. Structure of the kidney

10. The nephron Each kidney contains around a million tiny structures called nephrons, also known as kidney tubules or renal tubules The nephrons start in the cortex of the kidney, loop down into the medulla and back up to the cortex

11. Nephron in the cortex

12. How is the production of urine?

13. Ultrafiltration Arterioles branch off the renal artery and lead to each nephron, where they form a knot of capillaries (the glomerulus) sitting inside the cup-shaped Bowman’s capsule The capillaries get narrower as they get further into the glomerulus which increases the pressureon the blood moving through them (which is already at high pressure because it is coming directly from the renal artery which is connected to the aorta) This eventually causes the smaller molecules being carried in the blood to be forced out of the capillaries and into the Bowman’s capsule, where they form what is known as the filtrate This process is known as ultrafiltration The substances forced out of the capillaries are: glucose, water, urea, salts Some of these are useful and will be reabsorbed back into the blood further down the nephron

14. Filtrate of glomerulus

15. Reabsorption After the glomerular filtrate enters the Bowman’s Capsule, glucose is the first substance to be reabsorbed at the proximal (first) convoluted tubule This takes place by active transport People with diabetes cannot control their blood glucose levels and they are often very high, meaning that not all of the glucose filtered out can be reabsorbed into the blood in the proximal convoluted tubule As there is nowhere else for the glucose to be reabsorbed, it continues in the filtrate and ends up in urine

16. Deamination by the liver Excess amino acids absorbed in the blood that are not needed to make proteins cannot be stored, so they are broken down in a process called deamination The amino group of all amino acids - NH2 (which contains the nitrogen atoms) is removed, hence the term de-amin(o)-ation Enzymes in the liver split up the amino acid molecules The part of the molecule which contains carbon is turned into glycogen and stored The other part, which contains nitrogen, is turned into ammonia, which is highly toxic, and so is immediately converted into urea, which is less toxic The urea dissolves in the blood and is taken to the kidney to be excreted A small amount is also excreted in sweat

17. Composition of blood plasma and urine

18. Kidney disease and dialysis machine

19. The principle of kidney dialysis machine

20. What are the advantages and disadvantages between dialysis and kidney transplant?

21. Group Division 1 2 3 4 Daryl Sarah Jocelyn Johan Anastasha Shinbi Keira Jonathan Foyou Paulin Alenna Bryan Michell Yosia Jehiskiah Angel Michael Nico Radit Abigael Fernando Vivi Jessen Narendra Tachtyana Tesa Jeremy Chiecho Rhaka

22. Thank you