1. Excretory system
Alana
Skylar
Yesenia

2. How your Excretory system works
As your body performs the many functions that it needs in order to keep itself alive , it produces waste. These wastes are chemicals that are toxic and that if left alone would seriously hurt or even kill you. For example , as your cells brake down amino acids , they provide a dangerous toxic known as urea. The cells of your body excrete this urea into your blood.

3. Your kidneys
As your blood travels along within your body, it becomes more and more polluted with urea and other wastes. Eventually the blood enters a special filter, an organ known as your kidneys. As the blood enters your kidneys it is cleansed. Your kidneys remove the urea from the blood, sending it to your bladder for storage in the form of urine, commonly known as pee. It takes about 45 minutes for your kidneys to completely filter all of the blood in your body.

4. Your Bladder
Slowly your bladder fills up with the urine being produced by your kidneys. Eventually as it becomes full, you will feel a sensation telling your brain that you need to remove it from your body. Urine leaves your body through the process of urination, commonly known as peeing.

5. Interacting with Other Systems
The excretory system is a close partner with both the circulatory and endocrine system. The circulatory system connection is obvious. Blood that circulates through the body passes through one of the two kidneys. Urea, uric acid, and water are removed from the blood and most of the water is put back into the system.
The endocrine system is the major controller of the excretory system. As levels of compounds and fluids are monitored, kidney function must be constantly altered to provide the best internal environment for your cells. If you drink too much water, hormones are released that allow for more urine production. If you are dehydrated, less urine will be produced. The kidneys are also tied to the endocrine system with the adrenal gland position on the top of each kidney. The adrenals release adrenaline into your body.

6. Nasty Diseases
While there are many diseases of the excretory system, even more problems can be created by a malfunctioning set of kidneys. Blood pressure is closely tied to the amount of fluid in your body. If a kidney does not work and filter properly, blood pressure can increase to dangerous levels. If that weren't bad enough, urea would accumulate in your tissues and would slowly poison the cells of your body. People with malfunctioning kidneys often have to go through a process called dialysis where they are hooked up to a machine that filters their blood. The machine acts as an artificial kidney and tries to re-establish normal levels of ions and water in their bodies. Many people on dialysis are waiting for kidney transplants.

7. Regulation of Extracellular Fluids
Excretory systems regulate the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients. Components of this system in vertebrates include the kidneys, liver, lungs, and skin. Not all animals use the same routes or excrete their wastes the same way humans do. Excretion applies to metabolic waste products that cross a plasma membrane. Elimination is the removal of feces.

8. Nitrogen Wastes
Nitrogen wastes are a by product of protein metabolism. Amino groups are removed from amino acids prior to energy conversion. The NH2 (amino group) combines with a hydrogen ion (proton) to form ammonia (NH3). Ammonia is very toxic and usually is excreted directly by marine animals. Terrestrial animals usually need to conserve water. Ammonia is converted to urea, a compound the body can tolerate at higher concentrations than ammonia. Birds and insects secrete uric acid that they make through large energy expenditure but little water loss. Amphibians and mammals secrete urea that they form in their liver. Amino groups are turned into ammonia, which in turn is converted to urea, dumped into the blood and concentrated by the kidneys.

9. What Does This System Do?
What do those kidneys do? The regulation process of body fluids and salt levels is also called osmoregulation. The kidneys act as a filter. Eventually all of the blood in your body passes through the kidneys and they are able to do their filtering magic. The kidneys pull harmful molecules out of your blood .The kidneys are also key players in the hydration (water) levels for your body. Let's say you are in the desert and you haven't been drinking much water. Chemical signals are sent to your kidneys to reabsorb as much water as possible. The result is less urine creation and your body loses less water. A normal day has you creating about one and a half liters of fluid.bloodstream and leave the ones that are good for you.

10. Excretion Is Not Elimination
The excretory system is very important to your body and only has a few parts. In a similar way to removing solid waste from your body, you must also get rid of fluids. You know the results of the excretory system as urine. Urine is the result of the excretory system balancing the amount of water and salts in your body. We said the system is small. Your kidneys are the core organs involved in the excretory system. Related body parts include the ureters, bladder, and urethra. Once the urine passes through your urethra, that's it, it's out of your body.

11. Water and Salt Balance
The excretory system is responsible for regulating water balance in various body fluids. Osmoregulation refers to the state aquatic animals are in: they are surrounded by freshwater and must constantly deal with the influx of water. Animals, such as crabs, have an internal salt concentration very similar to that of the surrounding ocean. Such animals are known as osmoconformers, as there is little water transport between the inside of the animal and the isotonic outside environment. Marine vertebrates, however, have internal concentrations of salt that are about one-third of the surrounding seawater. They are said to be osmoregulators. Osmoregulators face two problems: prevention of water loss from the body and prevention of salts diffusing into the body. Fish deal with this by passing water out of their tissues through their gills by osmosis and salt through their gills by active transport. Cartilaginous fish have a greater salt concentration than seawater, causing water to move into the shark by osmosis; this water is used for excretion. Freshwater fish must prevent water gain and salt loss. They do not drink water, and have their skin covered by a thin mucus. Water enters and leaves through the gills and the fish excretory system produces large amounts of dilute urine

12. Excretory System Functions
1.collect water and filter body fluids. 2.Remove and concentrate waste products from body fluids and return other substances to body fluids as necessary for homeostasis. 3.Eliminate excretory products from the body.

13. Invertebrate Excretory Organs
Many invertebrates such as flatworms use a nephridium as their excretory organ. At the end of each blind tubule of the nephridium is a ciliated flame cell. As fluid passes down the tubule, solutes are reabsorbed and returned to the body fluids.

14. Vertebrates Have Paired Kidneys
ALL vertebrates have paired kidneys. Excretion is not the primary function of kidneys. Kidneys regulate body fluid levels as a primary duty, and remove wastes as a secondary one

15. The Human Excretory System
The urinary system is made-up of the kidneys, ureters, bladder, and urethra. The nephron, an evolutionary modification of the nephridium, is the kidney's functional unit. 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

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