Download The Kidneys

Learning Objectives:
•To know the role of the kidney
• To be able to label a diagram of the human
excretory system
•To be able to label a section through the kidney and
a nephron
•To understand the role of ADH and interpret data
about the presence of substances during the passage
through the kidney
To regulate the volume
and composition of body
fluids, removing waste
products from the body
and expelling the waste
and excess water from
the body in the form of
urine.
Your kidneys remove the poisonous substances which your cells produce.
Our bodies break down the protein in our food into amino acids. The
diagram shows what happens to these amino acids:
Amino acids
in blood
Some are
used for
growth and
repair
Protein in
your cells
Urea in
your blood
Some are not
used – they are
broken down in
the liver
Urea is made in the liver from amino acids. Urea
is a poisonous substance. Your kidneys remove
it from your blood. They also remove excess
salt (ions) from your blood. The urea and salts
are dissolved in water to make a liquid called
urine.
• The kidneys filter about 1.3 litres of
blood a minute.
• All the body’s blood flows through the
kidneys every 10 minutes, so blood is
filtered 150 times a day.
The renal vein
carries cleaned
blood away from
the kidneys
The kidneys
remove urea and
other waste
The bladder is a
bag that stores
urine
The urethra is a
tube which
carries urine out
of your body
The renal artery
carries ‘dirty’
blood (with
waste) into the
kidneys
Ureters are
tubes which
carry urine to
the bladder
The sphincter is
a ring of muscle
that keeps the
bladder closed
until you go to
the toilet
Renal artery
Medulla
Cortex
Nephron
within
the
kidney
Renal vein
Ureter
Pelvis
Capillary knot
Bowmans
capsule
Tubule
Collecting duct
Capillary
network
The diagram below shows a flattened section
of the nephron
‘Dirty blood’
Capillary
Useful substances are
reabsorbed into the blood
Useful substances
Bowman’s Capsule
Urine Urine
(urea and water)
Tubule
‘Cleaned
blood’
Urine goes to
the bladder
Urine
Blood is filtered
through the capillary
knot. Nearly all the
blood except red cells
filters through into the
nephron
‘Dirty blood’
The liquid in the nephron
contains useful
substances like glucose
and vitamins. These are
then absorbed back into
the blood (reabsorbed).
The liquid left in the
nephron is urine. It
contains urea and water
and other unwanted
substances. It then goes
through the collecting
duct and ureters to the
bladder.
Capillary
Useful substances are
reabsorbed into the blood
Useful substances
Bowman’s Capsule
Urine Urine
(urea and water)
Tubule
‘Cleaned
blood’
Urine goes to
the bladder
Urine
Complete the postcard to explain your journey through the
excretory system. You are a water molecule travelling through
the blood.
Dear Celia the Ciliated Epithelial Cell,
Wish you were here…
I have been on the most incredible
journey! It all started when…
Celia
Ciliated Epithelial Cells
Urinary Tract
Back
Front
of of
Postcard
Postcard
• If there is too little water in your blood then
the body detects this and the pituitary gland
produces anti-diuretic hormone (ADH).
• ADH increases the permeability
of the tubules, and allows the kidneys to
reabsorb more water, making a more
concentrated urine.
• The more ADH, the more
concentrated the urine.
Drag the boxes below to complete the table
Too much water in
body
Too little water in
body
Water in urine
Urine colour
Presence of ADH
A little
Yellow
A lot
More ADH
Colourless
Less ADH
90
Salt concentration (ml)
90
80
Volume of urine (ml)
80
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
0
30
60
90
120
150
Time after drinking (mins)
30
60
90
120
150
Time after drinking (mins)
------ normal level
Produce a leaflet for someone with a kidney problem, outlining
the advantages and disadvantages of the use of dialysis or
transplantation. Remember to use science to explain the
procedures and remember to use more than 2 sources of
information to improve the reliability.
• To know the role of the kidney
•
To be able to label a diagram of the human excretory
system
• To be able to label a section through the kidney and a
nephron
• To understand the role of ADH and interpret data about
the presence of substances during the passage through the
kidney
Learning outcomes
Click on the link to learn how to produce your own at home