Transcript Digestive & Excretory Systems

Excretory System
Functions
A. Remove liquid waste...what is this waste called?
B. Maintain water balance
C. Regulate blood pH
II. Composition of Urine
A. Water
B. Urea
1. Produced when amino acids are burned for
energy
C. Uric acid, salts and ammonia
D. Minerals, vitamins and heavy metals
I.
KIDNEY VIDEO
vakidney.mov
Excretory System
III. Anatomy and Function
A. Skin excretes excess water, salts and a small amount
of urea in the form of sweat
B. Majority of work is done by the kidneys
Renal Artery
Right Kidney
Ureter
s
Urinary Bladder
Left Kidney
Abdominal Aorta
Excretory System
C.
Waste-filled blood from the body enters the kidney
through the renal artery
Excretory System
D.
Inside the kidneys, nephrons filter out urea, excess
water, amino acids, drugs and other waste products
in the blood
Kidney
E.
Nephron
Filtered blood is returned to circulation via the renal
vein
IV. The Nephron
A. The kidney contains one million nephrons.
B. The nephron is the functional unit of the kidney.
Distal Tubule
Glomerulus
Arteriole
Collecting
Duct
Proximal Tubule
Capillary
Nephron Movie
V. The formation of urine
A. Filtration
1. Blood from the renal arteriole enters the glomerulus
2. The glomerulus has many large pores
3. Blood pressure forces all the small molecules out of the
blood stream into the proximal tubule.
4. Blood cells, proteins and other large molecules stay in
the blood.
Glomerulus
Arteriole
Proximal Tubule
B. Reabsorption
1. As the filtrate travels through the proximal tubule, most of
the water, minerals, and all of the glucose is reabsorbed
through the tubule wall back into the capillaries of the
nephron.
2. However, the tubule wall is impermeable to compounds
containing nitrogen.
*** What are these compounds?
a. Urea, ammonia and uric acid
Distal Tubule
Glomerulus
Arteriole
Proximal Tubule
Capillary
Collecting
Duct
C. Secretion
1. As the filtrate travels through the distal tubule, excess
H+ or NH+ are secreted into the filtrate.
***How does this help you?
a. This regulates the body’s pH.
2. By the time the filtrate has reached the collecting duct
it is now urine.
Distal Tubule
Glomerulus
Arteriole
Proximal Tubule
Capillary
Collecting
Duct
VI. Ureters
A. Urine leaves the kidneys and is carried to the urinary
bladder by the ureters.
VII. Urinary Bladder
A. Stores urine
B. When the bladder fills,
stretch receptors stimulate the brain.
C. The urge usually begins
when the bladder has
about 150 ml.
D. At 600 ml you get severe
pain which usually forces you to urinate.
VIII. Urethra
A. Carries urine to the outside of the body (passes 1-2 L per day)
IX. Disorders
of the
urinary system
A. Kidney Stones
1. Calcium, Magnesium or uric
salts in the urine crystallize
and form kidney stones.
2. These stones block the
ureters causing pain.
3. When the stones are passed
out of the urethra, the pain
can be very severe.
4. Ultra sound is used to break
them into smaller stones.
Guinness Book of Medical
World Records
Most kidney stones
produced As of April 16,
2003, Don Winfield of
Caledonia, Ontario, Canada,
has produced and passed an
excruciating 4,504 kidney
stones, ranging in size from
a grain of sand to a dried
pea.
Eventually, the kidney had
to be removed.
"At its worst," says Don, "I
produced 22 stones in 24
hours... and 35 over a
period of five days."
B. Urinary Tract Infection (UTI)
1. Caused by a bacterial infection of any part of the
urinary tract…How is it treated?
C. Kidney Failure
1. One or both kidneys are damaged by disease or injury
2. Treatment is renal dialysis or transplant
Dialysis
Blood in tubing flows through
dialysis fluid
Blood pump
Artery
Used dialysis fluid
Shunt
Air
detector
Dialysis
machine
Fresh
dialysis
fluid
Compressed air