Kidneys and Excretory System
How Urination works
• http://health.howstuffworks.com/adam-200032.htm
Excretion
• The process of excretion involves the removal of metabolic waste.
• If wastes build up in the body, they become toxic.
• There are 4 main organs that work to remove waste from the body.
Excretion con’t
1. The skin - removes waste heat, some urea, and other
materials found in sweat2. The lungs - removes C023. The large intestine - removes solid wastes of the digestive process4. The kidneys - removes urea, uric acid, extra water and salts
Anterior View of the Urinary System
Posterior View of the Urinary System
Questions page 380 1-3
1. List 3 main functions of the kidney.
a. Eliminates wastes
b. regulation of water balance
- Also regulation of pH
- Also regulates blood pressure and is involved in the production of red blood cells.
Questions page 380 1-3 con’t
2. What is deamination and why is it an important process?
- Deamination is the removal of the amino groups from a protein (organic compound)
- Amino groups = 2 H + 1 N
Questions page 380 1-3 con’t
2 con’t
- Deamination occurs in the liver
- Important to convert excess amino acids into carbohydrates and other nutrient compounds
Questions page 380 1-3 con’t
3. How does the formation of urea prevent poisoning?- Deamination produces ammonia, a water soluble gas.
- Ammonia is extremely toxic and cannot be stored in the body.
- The liver combines two molecules of ammonia with carbon dioxide to form urea.
- Urea is 1000 times less toxic than ammonia.- Animals can store urea for short periods of time in their
bodies- Permits the controlled excretion of urine
Questions page 383 4-5
4. State the function…
Bowman’s capsule: The filtration of water and dissolved solutes happens as blood is forced from the glomerulus to the Bowmen’s capsule
Proximal tubule: Selective reabsorption of nutrients from filtrates back into the blood
Loop of Henle: Reabsorption of water and salt
Distal Tubule: secretion of substances from the blood to the urine
Collecting duct: Urine formation
• The urethra is the only part of the urinary system that differs between males and females. It is longer in males.
Questions page 319 4-5 con’t
5. List and describe the 3 processes involved in urine formation.
a. Filtration – involves the movement of fluids from the Bowman’s capsule to the glomerulus.
b. Reabsorption – involves the movement of fluids from the nephron into the interstitial fluid and eventually the capillary net.
c. Secretion – involves the selective transport of fluids from the capillary net into the nephron.