The Human Excretory System functions to: Remove waste from the body (e.g
urea) and control/regulate water levels. The system includes the kidney and its
functioning component; the nephron
Kidney - Filter the waste products in the blood (e.g urea)
Aorta - Carries blood to kidney from heart
Vena Cava - Carries blood from kidney to heart
Renal Artery - Blood from aorta to kidney
Renal Vein - Blood carried from kidney to vena cava
Ureter - Carries waste from kidney to bladder
Bladder - Stores waste products
Urethra - Waste products from bladder out
Cortex - Outside of kidney
Medulla - Where filtering occurs in the nephron
Pelvis - Ureter meets the medula
The nephron is
the cortex but
loop of henle
passes through
the medulla and
because the
loop of henle
does the work it
has been put in
the medulla
Treating kidney failure:
Transplant & Dialysis
Parts of kidney: Renal Artery, Outer membrane, Nephron (2mill),
Cortex, Medulla organised in pyramids, Pelvis, Ureter & Renal Vein
Stomata are pores on a
plant, usually found on the
underside of the leaf. They
release water vapour into
the atmosphere - this is
called transpiration. They
also allow gas exchange
to take place
Stomata can open and close
to regulate transpiration. If the
stomata are closed or covered
by certain substances, and
cannot release water vapour,
the plant cannot take up as
much, or possibly any more
water at the roots. The
difference between the bottom
of the leaf and the top is that
the bottom has more stomata
than the top
Excretion and Homeostasis
Excretion - Removal of waste products from cells
Skin - Excretes sweat, containing water, ions and urea
Lungs - Excrete carbon dioxide and water
Liver - Excretes bile, bile pigments, cholesterol and mineral ions
Gut - Excretes gut mucosal cells, water, bile and faeces
Kidneys - Excrete urine, containing urea, mineral
ions, water and other foreign chemicals from the blood