1. Biology Powerpoint #5

2. Through lungs, skin, and kidneys.
Function: The excretory system eliminates nonsolid wastes from the body.
skin
lungs
kidneys
ureters
urinary bladder
urethra
Through lungs, skin, and kidneys.
Lungs exhale carbon dioxide and water vapor.
Sweat glands in skin release excess water and salts.

3. The ureters are tubes that carry urine from the kidneys to the urinary bladder.
The urinary bladder temporarily stores urine until it is released from the body.
The urethra is the tube that carries urine from the urinary bladder to the outside of the body.
The outer end of the urethra is controlled by a circular muscle called a sphincter.
skin
lungs
kidneys
ureters
urinary bladder
urethra

4. Function of the Kidney
Filter blood in order to remove cellular waste products.
At any given time, 20 % of blood is in the kidneys. Humans can function with one kidney.
If one stops working, the other increases in size to handle the workload.

5. The kidneys help to maintain homeostasis by filtering the blood.
cortex
medulla
renal artery
renal vein
ureter
(to bladder)
The kidneys are fist-sized, bean shaped structures.
two layers: medulla and cortex
filtering units called nephrons
renal artery and renal vein

6. The kidney can also excrete of other waste products, such as :
1) urea a nitrogen-based waste produced in the liver from the breakdown of protein. It is the main component of urine
2) uric acid usually produced from breakdown of DNA or RNA
3) creatinine waste product of muscle action.

7. Kidneys have three basic functions in maintaining homeostasis.
remove waste from blood
help to maintain electrolyte, pH, and fluid balances
release key hormones

8. Nephrons clean the blood and produce urine.
Nephrons are the filtering units in the kidneys.
They clean and rebalance the blood to produce urine.
There approximately 1 million nephrons in each kidney
from body
to body
to body
loop of Henle
from other nephrons

9. The body’s entire volume of blood is filtered every 45 minutes
Nephrons clean the blood in a three-step process.
The first step is filtration of the blood.
FILTRATION
Water and other small molecules diffuse out of the blood. 1
Glomerulus: Network of capillaries
Bowman’s Capsule: Encases the glomerulus
Glomerulus
The body’s entire volume of blood is filtered every 45 minutes
Bowman’s capsule

10. The second step is reabsorption of materials.
The first step is filtration of the blood.
The second step is reabsorption of materials.
REABSORPTION
Most of the material is reabsorbed into the blood. Materials not reabsorbed make up the urine. 2
from body
collecting duct
to body
from other nephrons
loop of Henle

11. The third step is excretion of materials.
The first step is filtration of the blood.
The second step is reabsorption of materials.
The third step is excretion of materials.
from body
EXCRETION
In the loop of Henle, water can be reabsorbed one final time to reduce the volume of urine. 3
collecting duct
to body
from other nephrons
loop of Henle

12. Injury and disease can damage kidney functions.
A kidney transplant can replaced damaged kidney.
recipient and donor tissue must match
drugs prevent tissue rejection
The daughter and son in this photo donated a kidney and liver tissue to their mother.

13. Dialysis can be used to filter and clean the blood.

14. UTI (Urinary Tract Infection)
Disorders of the Excretory System
UTI (Urinary Tract Infection)
Is a very common disorder. It is an infection of the urethra or bladder.
Symptoms include painful urination (burning sensation), frequent urination (even if no urine present) and bloody or brown urine.
This can lead to chills, fever, nausea, vomiting and upper abdomen tenderness.

15. Cure / Prevention :
If left untreated, all UTI’s can lead to permanent kidney damage and possible kidney failure.
Treatment is by antibiotics. A person needs to maintain good personal hygiene when eliminating wastes (liquid and solid forms) from the body.
Prevention: A person should drink lots of water.

16. Kidney Infections
Result when an infection reaches the kidneys
Common causes can be infection from elsewhere in the body or obstruction of the prostate gland (usually in older men).
For children, infection can be caused by the tube that drains urine from the kidneys and the bladder.

17. Kidney Stones Cause: Crystals formed from minerals in urine.
They can be found in the kidney, ureter or bladder.
80% of those stricken are males.
The most common crystals are:
Calcium Oxalates
Uric acid

18. Kidney Stones (cont)
Symptoms include severe back or abdomen pain, blood in the urine, nausea and vomiting.
Treatment may vary from letting the stones pass through the urinary tract to ultrasound shock to disintegrate the stones to a small size that can be passed through the urinary tract.
Large stones require surgery for removal.

19. Kidney Stones (cont) Prevention: Ways to avoid kidney stones:
Increase liquid intake (more than 2l / day)
Limit sodium intake
Limit animal protein
Limit foods high in oxalate (spinach, strawberries, nuts, dark chocolate, brewed tea)