Transcript Shining Purple Curves - IB

The Kidney
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11.3.1 Define excretion
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The kidney
• Excretion is the
removal from the
body of waste
products of
metabolism
Urea is a
waste
product.
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Excretion
• Urea is a waste product from the
metabolism of amino acids. Each amino
acid must be deaminated (lose an amine
group).
• It is the job of the kidneys to filter and
cleanse the bloodstream of molecules like
urea and other molecular wates.
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How do Kidneys work?
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11.3.2 Draw and label the
structures of the kidney
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Excretory System filters blood and
produces urine.
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The Kidney
• Renal artery – takes
blood into the kidney
• Renal vein – blood
drains out of the kidney
• Renal pelvis – area
where urine collects
• Ureter – takes urine to
bladder
• Renal medulla –
surrounds renal pelvis
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11.3.3
Annotate a diagram of a
glomerulus and associated nephron to
show the the function of each part.
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Glomerulus
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Nephron
 Kidneys made up of 1.25
million nephrons
 Nephron = filtering unit
 Capillary bed = glomerulus
 Bowman’s capsule =
surrounds glomerulus
 Proximal convoluted tubule
 Loop of Henle
 Distal convoluted tubule
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11.3.4 Explain the process of
ultrafiltration, including blood
pressure, fenestrated blood
capillaries and basement
membrane
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The kidney is the blood’s filtration
and balancing system
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Balancing the Blood
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Nephron
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Nephron
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Ultrafiltration – in the renal capsule
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Explain the process of
ultrafiltration. (8 marks)
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Explain the process of
ultrafiltration. (8 marks)
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11.3.5 Explain osmoregulation
• Osmoregulation is the control of the water
balance of the blood, tissue or cytoplasm
of a living organism
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Osmoregulation
• Depends on:
– Total volume of
water ingested
recently as liquid &
in solid foods
– Perspiration rate
(exercise level &
environmental
temperature)
– Ventilation rate
(breathing rate is
largely dependent
on exercise level
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11.3.6 Explain the reabsorption
of glucose, water and salts in the
proximal convoluted tubule,
including the roles of microvilli,
osmosis and active transport.
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Selective Reabsorption
 Filtrate leaving
Bowman’s capsule
contain substances
body needs
 Water, salt ions,
glucose
 Occurs in the
proximal convoluted
tubule
 Returned to
bloodstream in
peritubular capillary
bed
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Selective Reabsorption
Walls of
the prox.
conv.
tubule is
one cell
thick
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Selective Reabsorption
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Selective Reabsorption
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Selective Reabsorption
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Explain selective reabsorption in
the kidney (8 marks)
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Explain selective reabsorption in
the kidney. (8 marks)
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11.3. 7 Explain the roles of
the loop of Henle, medulla,
collecting duct and ADH in
maintaining the water balance
of the blood
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Loop of Henle
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Loop of Henle
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Loop of Henle/medulla
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Collecting ducts
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ADH = antidiuretic
hormone
Collecting Duct
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Water concentration in the
blood
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Explain osmoregulation in the
kidney (8 marks)
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Explain osmoregulation in the
kidney (8 marks)
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11.3. 8 Explain the differences
in the concentration of proteins,
glucose and urea between
blood plasma, glomerular filtrate
and urine
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Tables don’t have to be memorized
Fluids mentioned associated with the following
locations.
Urine = fluid which
was the filtrate that
has now undergone
reabsorption &
osmoregulation
mechanisms & is
taken to the
bladder
Glomerular filtrate =
fluid (now called
filtrate) which enters
into the proximal
convoluted tubule
after the ultrafiltration
process within
Bowman’s capsule.
No reabsorption has
occurred.
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Which nutrients are 100% reabsorbed?
Glucose and amino acids
Where does this happen?
selective reabsorption in the proximal
convuluted tubule
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What is filtered, reclaimed and excreted
by the kidney?
The concentration of uric acid is 12.5x greater in the urine than in the filtrate or the blood.
How much more concentrated is urea in the urine than in the blood?
Why is such a large proportion of urea and uric acid excreted?
They are very toxic
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What is filtered, reclaimed and
excreted by the kidney?
What percentage of the following are forced into the
nephron by ultrafiltration?

urea – 100%

glucose – 100%

inorganic salts - 100%

proteins & macromolecules - 0%
Why the macromolecule result?
Too large for
ultrafiltration
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Are there any other components
not processed by ultrafiltration?
• Erythrocytes
• Lymphocytes
• platelets
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11.3.9 Explain the
presence of glucose in the
urine of untreated diabetic
patients.
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Diabetes and the Kidney
• Type I : insulin not produced
– Liver does not take up glucose from blood
Type II: insulin receptors inactive
- Liver does not take up glucose from blood
Results: Blood sugar concentration remains high
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In the Kidney
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Diabetes & the Kidney
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From your heart to the Toilet
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