HRB –KEDS funded
Kidney Health Matters Fact sheet
The healthy kidney
Written by Danielle Nicholson
The kidney is part of the excretory system whose main role is
maintaining balance or homeostasis. Other organs in this system include
the ureters, the bladder and the urethra. The main function of the kidney
is to regulate body fluids. Filtration and reabsorption take place in
distinct regions of the kidney.
A person has two kidneys, one
on each side of their body.
Each kidney is roughly the size
of a person’s fist. They are
delicate organs and are placed
well, protected by ribs, muscle,
fat and skin.
Did you know?
Kidneys regulate blood
pressure, stimulate the
making of red blood cells
and maintain the body's
vitamin D and calcium
levels.
To stay healthy and perform their function, kidneys must have a constant flow of
oxygen-rich blood. Blood arrives to the kidneys via the aorta and renal arteries
(see the diagram below in red). The kidneys clean this blood of waste products
and make urine. Urine travels from the kidneys to the bladder through the ureters
and leaves the body through the urethra. Renal veins (diagram in blue) return the
cleaned blood to the rest of the body. Nephrons are the filtering units of the kidney.
b
Urine formation in the nephrons
a
c
d
e
f
Blood flows through a tight knot of
capillaries called the glomerulus (a)
where water and chemicals flow with
force into the Bowman’s capsule (b).
Then the glomerular filtrate passes
through the proximal convoluted
tubule (c) where reabsorption of
glucose, amino acids, some salts and
water are reabsorbed into the blood
(d) by osmosis, diffusion and active
transport. More water is reabsorbed
in the Loop of Henle (e) and the distal
convoluted tubule (f). Urine passes
into the pelvis (inner region) of the
kidney then onto the bladder for
storage.
The healthy kidney
Written by Danielle Nicholson
HRB –KEDS funded
Kidney Health Matters Fact sheet
The kidneys are highly vascular,
sensing organs that regulate blood
pressure, red blood cell formation and
vitamin D metabolism.
When kidney function becomes
impaired, complications arise. Blood
pressure can become abnormal. In
some instances of kidney disease, a
lack of an essential hormone for the
production of red blood cells,
erythropoietin (EPO), causes anaemia.
Bone disease may result if there is an
imbalance of calcium and phosphorous
in the blood. If too much phosphorous
is present, calcium levels must also
raise. Calcium will be pulled from the
bones to strike the correct balance.
Did you know?
The key nutritional recommendations for
kidney health include limiting sodium to
2500 mg per day and protein to 3-5 oz (85140 g) of high quality protein, avoiding nonnutritional sources of phosphorous (colas,
beer and chocolate) and drinking fluids as
thirst dictates.
For more information about kidney health and
disease, please consult the array of educational
resources assembled on our Facebook page,
Kidney Health Matters.
The outer layer or region of
the kidney is the cortex, the
middle region is the medulla
and the innermost region of
the kidney is the pelvis.