2Excretion vs. Elimination Your body makes several kinds of waste, which fall into two groups:Undigested solid wastesWastes made by cells
3EliminationUndigested solid waste leaves your body through the large intestineWater is removed from the wastes in the large intestine, which allows for the formation of a solid (feces).
4The solid wastes moves from the large intestine to the rectum. From the rectum, the solid waste is excreted through the anus.
5ExcretionWhen waste products made by cells (water, heat, carbon dioxide, salts, urea) leave your bodyIn many animals, CO2 leaves the body through the lungsThe liquid waste, urine, is made in the kidneys
6Urine: made up of water, heat, harmful chemicals (urea), and some salts Perspiration: when heat, water, and salt are excreted by the body through skin (i.e. sweating)
7Write the correct waste product next to the excretory organ: 1. Skin =2. Large intestine =3. Lungs =4. Kidneys =(word bank: carbon dioxide, solid wastes, salt, harmful chemicals, water, heat)
11LungsWhen we breathe, we excrete CO2 waste, and small amounts of heat and waterFact: your lungs are capable of removing alcohol from the blood; this is how a breathalyzer is able to determine a person’s blood alcohol level
13Skin Largest organ; excretes most of the body’s waste heat Also removes some water, salts, and very small amounts of ureaPerspiration: helps the body ‘cool off’When sweat evaporates from the skin, it cools the body, removing heat
15KidneysFist sized, bean shaped (i.e. kidney bean) organs found on either side of the lower spineMain job is to filter out wastes from the blood, making them more concentrated in preparation for excretion and, in the process of doing this, retaining as much water as possible
17The blood enters the kidney through the renal arteries; renal veins carry blood back from the kidneys to the bodyA ureter connects each kidney to the urinary bladder; once urine has formed, the ureter carries the urine (produced after the blood has been filtered for wastes) from the kidney to the bladder
22NephronsThe filtration of the blood takes place in minute structures called nephrons, found in the cortex, which is the outer layer of the kidneyThe nephrons estimate at more than 1 million per kidney
25In spite of their size, the kidneys filter more than 180 L of blood every 24 hours Most is reclaimed by the body, only 1.5 L of urine is passed each dayYour blood passes through the kidneys 300 times per day
28Liver A secondary organ of excretion Does not excrete wastes, but is important for excretionHandles cell wastes in several ways:1) Breaks down dead red blood cells: pass into digestive tract, then eliminated with solid waste by the bowels
292) Weakens certain harmful substances 3) Changes some harmful substancesEx: the liver makes bile from harmful substances – bile is important in fat digestion – after bile works on fat, it is eliminated from the bowels4) Combines certain harmful chemicalsEx) liver combines ammonia and some CO2 – forms urea, which the blood carries to the kidneys where it becomes part of the urine