Kidney in Detail

1
Kidney in Detail

• Standard Grade Biology

2
Excretion by the Kidney

• Urea
• -nitrogenous waste
• -made by liver
• -excess amino acids in blood
• -toxic
• Why must nitrogenous waste be excreted?

3
1 Filtration by the Kidney

• Supplied with blood from renal artery
• Inside it splits into many fine capillaries
• Each capillary supplies blood to hundreds of
  thousands of tiny filtration units called nephrons

Renal artery
Lets have a look at a nephron!!!
Renal vein
Ureter
4
(No Transcript)
5
(No Transcript)
6

• Glomerulus brings a large surface area of blood
  capillaries in close contact with Bowmans
  capsule
• 2. Liquid filtered from blood under pressure
  (filtration)
• Glomerular filtrate produced containing
• -water
• -glucose
• -salts
• -urea
• (Protein molecules and red blood
• cells do not pass into tubule as
• they are TOO BIG!!!!)

Blood from renal artery enters wide capillary
Blood travels through narrow capillary towards
renal vein
Filtration
Glomerular filtrate
7
Think

• Which feature of the glomerulus helps the process
  of filtration?
• Which 4 components of unfiltered blood appear in
  the glomerular filtrate?
• Why do blood cells and protein molecules not
  appear in the glomerular filtrate?

8
Key Words!!

• Nephron structure in the kidney that acts as
  a microscopic filtration unit
• Glomerulus dense mass of very fine blood
  capillaries at the nephron that act as a
  filter
• Bowmans capusle cup-shaped part of the
  nephron that holds a glomerulus and
  collects the products of filtration from it
• Glomerular filtrate liquid removed from the
  blood by filtration in the kidney

9
2 Reabsorption by the Kidney

• Once the main components of glomerulur filtrate
  enter the bloodstream
• -they are no longer in bloodstream
• If nothing more happened in the nephron then all
  the useful stuff would be lost in the urine!
• Therefore, glucose, water and some salts need to
  be reabsorbed!

10
(No Transcript)
11
Think.

• Which three components of the glomerular filtrate
  are reabsorbed?
• Why is it important for these to be reabsorbed?
• Which substances are present in the final urine?

12

• Summary of kidney function

13
2 Controlling Water Concentration

• Blood
• -important part of internal environment
• -constantly changing water concentration
• -e.g. exercising
• drinking lots of water
• The body uses negative feedback control to
  regulate water content of the blood

14
How does it work?
15

• Control of Water animation

16
This powerpoint was kindly donated to
www.worldofteaching.com http//www.worldofteac
hing.com is home to over a thousand powerpoints
submitted by teachers. This is a completely free
site and requires no registration. Please visit
and I hope it will help in your teaching.