Human Organ Systems The Excretory System

What is the function of the Excretory system? The job of the excretory system is to remove metabolic wastes from your body. Metabolic wastes are those that are created by the life processes within your cells. Remember that the wastes removed from your body by your digestive system (Feces) are not considered metabolic wastes.

The rule of 4 For this organ system, 4 is a magic number to remember. For instance, there are 4 metabolic wastes created by your body. Water Carbon dioxide Salts Urea

More on 4 Not only are there four metabolic wastes, there are 4 organs* that remove these wastes. Skin Lungs Liver Kidneys* *(There are actually 4 components which make up our urinary system.) 1. Kidneys 2. Ureters 3. Urinary bladder 4. Urethra

The Skin The largest organ in your body, the skin gets rid of metabolic wastes in the form of sweat. Sweat consists of water, salts and urea. The sweat is formed in specialized sweat glands in your skin.

The Liver While your liver does not excrete anything from your body, it is responsible for filtering your blood and forming a nitrogenous waste called urea. Once formed, the urea is then secreted back into your blood. It’s molecular formula is (NH2)2CO2 Thought question: Since Urea is a nitrogenous compound, from which component of human nutrition is this waste derived from?

The Lungs Your lungs help to get rid of two metabolic wastes: CO2 H2O These wastes diffuse from the capillaries in your alveoli. Normal lung Lung Cancer Emphysema Lung

The urinary system This system consists of 4 components. 1. Your Kidneys: You kidneys filter your blood and remove Urea, excess water and salts. These are combined to form Urine. 2. The ureters are tubes that transfer urine from the kidneys to the urinary bladder. 3. The urinary bladder is a temporary holding sac for urine. 4. The urine leaves your body through your uretha. In males, the urethra is also part of the reproductive system.

Quik quiz Please turn over your note worksheet and try to answer the following questions. 1. Name the four metabolic wastes. 2. Name the four organs involved in excretion. 3. Where are metabolic wastes created? 4. Which chemical reaction(s) in your body produces water? 5. Which chemical reaction produces salt?

Excretion Summary Organ Function/Wastes excreted Skin Excretes water, salts and urea in the form of sweat. Liver Filters blood of nitrogenous wastes and creates Urea. Lungs Excretes water and carbon dioxide during exhalation. Kidneys Filters blood of Urea, Salts and water and creates Urine. Excretes urine with help from the ureters, urinary bladder and urethra.