1. Metabolic Waste Removal
Excretory System
Metabolic Waste Removal

2. Organs of Excretory System
Lungs – CO2 and water
Skin - Sweat
Kidneys – Urine
Liver – detoxification of blood
These organs work with other body systems to keep the body in homeostasis.

3. Excretion
Excretion – is the process by which waste and excess substances are removed from the body.
If wastes from metabolism (metabolic wastes) are not removed from the body, the body will die.
Metabolic wastes come from chemical reactions in the cells of the human body

4. Major Metabolic Wastes
Carbon Dioxide
Nitrogen compounds
Ammonia
Urea
Uric acid
Mineral Salts
Sodium chloride
Potassium sulfate
All of these wastes are poisonous to the body in high concentrations

5. Nitrogen wastes
Nitrogen wastes are a by product of protein metabolism.
Amino groups are turned into ammonia, which in turn is converted to urea, dumped into the blood and filtered out by the kidneys.
Ammonia is converted to urea, a compound the body can tolerate at higher concentrations than ammonia.

6. Role of the Liver
Removes harmful substances such as bacteria, certain drugs, and nitrogenous wastes from the blood
In the liver the substances are changed into inactive or less poisonous forms
Inactive substances (urea) are returned to the blood stream and filtered and excreted by the kidneys.

7. The Skin
The skin performs a number of different functions one of them is excretion of wastes.
In sweat there is a small amount of urea and salts.
Sweat 99% water 1% Urea and Salts

8. Lungs
Excrete CO2 and Water
The end products of cellular respiration

9. Urinary System
Waste is filtered from the blood and collected as urine in each kidney.
Urine leaves the kidneys by ureters, and collects in the bladder.
The bladder can distend to store urine that eventually leaves through the urethra
The urinary system:
Kidneys
Ureters
Bladder
urethra

10. Urinary tract
Kidneys
Ureters
Bladder
Urethra
Prostate
Male
Female

11. Kidneys Bean shaped organs that are about 10cm long Main Functions:
Remove wastes of cellular metabolism (metabolic waste)
Regulate the concentrations of the substances in the blood

12. Kidneys (1)

13. Kidneys (2)

14. Structure of the Kidneys
Kidney is made up of 3 parts
Cortex – outer part
Medulla – middle part
Pelvis – inner part
Blood is filtered in the cortex
Collecting ducts extend through the medulla
The filtered substances, called the filtrate, collect in the pelvis which are connected to the ureter

15. Cross Section of Kidney

16. Nephrons
MOST important job of the kidney is to filter waste from blood
The filtering is done by the nephron.
There are about 1.25 million nephrons in each kidney

18. Components of The Nephron
Glomerulus: Arteriole blood is filtered under high pressure.
Bowman's Capsule: surrounds the glomerulus and collects the filtrate

19. Bowman capsule

20. Component of Nephrons Continued
Proximal Convoluted Tubule
Loop of Henle
Distal Convoluted Tubule
All of these nephron structures aid in the reabsorption of materials needed for the body.

22. Nephron (1)

23. The Nephron Function
The nephron consists of a ball of blood capillaries called the glomerulus
Blood flows into the kidney through the renal artery, which branches into capillaries associated with the glomerulus.

24. The Nephron Function Continued
Arterial pressure causes water and solutes from the blood to filter into the Bowmans Capsule which surrounds the glomerulus
The Filtrate flows through the proximal convoluted tubule, loop of Henle, and then into the distal convoluted tubule.
The distal tubule empties into a collecting duct. Which carries urine to the pelvis of the Kidney

26. The nephron has three functions:
Glomerular filtration of water and solutes from the blood.
Tubular reabsorption of water and conserved molecules back into the blood.
Excretion of urine from collecting tubes

27. WOW that’s a big filter
Nephrons filter 125 ml of body fluid per minute; filtering the entire body fluid component 16 times each day.
In a 24 hour period nephrons produce 180 liters of filtrate, of which (99%) liters are reabsorbed.
The remaining 1.5 liters forms urine.

28. Disruption of Kidney Function
Infection, environmental toxins such as mercury, and genetic disease can have devastating results by causing disruption of kidney function. Many kidney problems can be treated by dialysis, where a machine acts as a kidney. Kidney transplants are an alternative to dialysis.