GCSE BIOLOGY EXCRETION IN HUMANS

GCSE BIOLOGY EXCRETION IN HUMANS

HideShow resource information
  • Created by: Hugo
  • Created on: 28-02-10 23:47
Preview of GCSE BIOLOGY EXCRETION IN HUMANS

First 114 words of the document:

Excretion in Humans
Urinary system
Kidney Structure
2 kidneys
Outer part of kidney is the Capsule, an outer skin hold the kidney together
Underneath this is the cortex which is where the capillary knots and Bowman's capsule can be found. Blood
is filtered here ­ process is called ultrafiltration
Medulle lies under the cortex, this helps with the reabsorbtion of water. Here the loop of Henle (part of
kidney tubule) is found.
Pyramids are formed from collecting ducts that bring urine from the kidney tubule.
These lead into the pelvis, which leads into the ureter carrying urine to the bladder to be stored.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Osmoregulation
Water levels in the body must be monitored to keep between acceptable levels.
The hypothalamus (in the brain) monitors the concentration of the blood. If it's too weak it will do nothing so
the kidney gets rid of more water making the urine dilute.
If the concentration of the blood is too high then water must be conserved. The hypothalamus stimulates the
pituitary gland which releases ADH (Anti-diuretic hormone).…read more

Page 3

Preview of page 3

Here's a taster:

Along the length of each capillary is a knot called a glomerulus.
Capillary entering the glomerulus is wider than the capillary leaving it so the pressure inside the glomerulus is
high. This forces some of the blood plasma of the vessels. Proteins and blood cells are too big to leak out.
But smaller particles like water, salts, urea, glucose and amino acid leak of the capillary and are termed
the glomerular filtrate. This filtrate is collected in a cup structure ­ Bowman's Capsule.…read more

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »