Download The kidney – structure and function

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The kidney – structure and function
Kidneys filter the blood, removing waste such as urea and balancing the water content.
Urine production
Ultrafiltration creates the glomerular filtrate. As substances such as glucose, amino acids, salts and
water are selectively reabsorbed, the concentration of urea rises. Only a small proportion of the original
glomerular filtrate remains to become urine.
wider
narrower
Efferent
arteriole
Afferent
arteriole
The structure
and mechanisms
of action of the
nephron in the
mammalian kidney
Glomerulus
Bowman’s
capsule
cortex
Selective reabsorption
1. Cells of the proximal convoluted tubule
actively transport Na1 into the surrounding
tissue fluid.
2. Na1 with glucose or amino acids enter these cells
from the filtrate through co-transporter proteins.
3. Water follows
down a water
potential gradient.
proximal convulated tubule
Ultrafiltration
• High pressure in glomerulus
to the
• Fenestrations (gaps) in
renal vein
capillary endothelium
• Podocytes (epithelial cells with
hairpin
finger-like projections) create
counter current
gaps in the lining of the
mutiplier
Bowman’s capsule.
position of nephron
tubule
capsule
cortex
Water moves by
osmosis, down a
water potential
gradient from the
tubule back into
the blood.
medulla
Na1
1Cl2
H2O
medulla
H2O
Loop of
Henle
No water loss
Na1 as ascending
1Cl2 limb is not
permeable to
water
Decreasing
water potential
of the tissue fluid
Na1 and Cl2
enter the
bloodstream.
branch of renal vein
branch of renal artery
A longitudinal section of
the kidney showing the
position of the nephron
pelvis
ureter
A student prepared a cross-sectional slide of the
kidney cortex. Label three structures visible in the
image of this slide below.
In sections of the kidney, look for empty spaces
and ‘crescent’ shapes to identify the Bowman’s
capsule, and darker staining and concentrations
of nuclei to identify the glomerulus.
glomerulus
Bowman’s
capsule
proximal/distal
convoluted tubules
96
(3 marks)
If a person suffering from chronic high blood
pressure finds blood in their urine, what might have
caused this? (2 marks)