The kidney is made up of approximately 1 million filtering units called nephrons. Each nephron contains a glomerulus for initial blood filtration and a tubule for reabsorption and waste excretion. The kidneys play crucial roles in regulating blood pressure, electrolyte balance, and removing waste from the blood in the form of urine. Common kidney functions include filtering the blood, reabsorbing necessary nutrients, and secreting hormones to support other bodily processes. Damage to the kidneys can impair these functions and potentially lead to serious health issues like kidney failure.

1. Kidney Structure & Function
Austin & Alison
Biology 20

2. The Kidney

3. Structure
• Nephron
▫ Long tube that runs from the cortex into the
medulla
▫ There are approximately 1 million in each kidney
▫ Starts as the glomerulus, becomes the Bowman’s
capsule, descends into the medulla as the Loop of
Henle, then becomes the distal convulated tubule.
▫ Main function is to filter the blood, reabsorb what
is needed, and excrete the rest as urine.
▫ Eliminates waste, regulates blood pressure and
pH.

4. Structure Cont.
• Glomerulus
▫ Network of capillaries that perform the first step of
filtering blood.
▫ Glomerulus are unique because they drain into an
artery, rather than a vein.
▫ This causes the pressure in the capillary to be high to
increase filtration.
▫ The rate at which glomerulus filter is known as
Glomerulus Filtration Rate or GFR.
▫ GFR can be increased by high blood pressure.
Decreased GFR could be a sign of kidney disease or
damage.
▫ Average GFR is 140-(your age)

5. Structure Cont.
• Proximal Convoluted Tube
▫ Leads the Bowman’s capsule to the Loop of Henle
▫ After proteins and sugars are filtered out of the
blood, some of it needs to be returned. This
happens in the PCT.
▫ The edge of the tube is covered in microvilli to
allow for maximum absorption.
▫ If nutrients or sugars are urinated out, this could
be a sign of disorder in with your kidney function.

6. Secretions
• The kidneys secrete a variety of hormones.
• Low levels of oxygen or hypoxia detected in renal
circulation cause hormone release.
• The active form of vitamin D promotes the
intestinal absorption of calcium and the renal
reabsorption of phosphate.

7. Functions
• The kidneys play a role in regulating many of the
body’s functions including electrolytes,
acid/base balance, and blood pressure.
• The are a “natural filter,” similar to a coffee filter
(glomerulus, Bowman’s Capsule) for the body,
sending unwanted wastes to the urinary bladder.
• Responsible for the reabsorption of water,
glucose and amino acids.
• Produce hormones needed for normal bodily
functions.

8. Functions Cont.
• The kidneys are located in the rear of the
abdominal cavity.
• Each excretes urine into a ureter, which empties
into the urinary bladder.
• Renal arteries and veins carry blood to and away
from the kidneys.

9. Pyelonephritis
• Urinary tract infection that has reached the
pelvis of the kidney.
• Several cases of this can lead to pus
accumulation around the kidneys, inflammation,
kidney failure, and in extreme cases, death.
• Symptoms are accelerated heart rate, painful
urination, abdominal pain, and nausea.
• This infection can be caused by bacteria entering
the urinary tract, and is usually treated by
antibiotics.

10. Bibliography
• http://www.virtualmedicalcentre.com/health-
investigation/glomerular-filtration-rate-gfr/54#C6
• https://en.wikipedia.org/wiki/Kidney
• http://www.google.ca/imgres?imgurl=http://www.inter
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