Animal Systems THE SKELETAL SYSTEM The skeletal system is made up of ______________, ______________, and ______________. The skeletal system has two functions: to ______________ ______________ ______________ and give ______________. It works hand in hand with the muscular system. The bones can't ______________ on their ______________. Muscles provide the ______________ that animals need to produce ______________. They're attached by tough rubbery ______________. When the muscle ______________ the bone will move. Muscles that cause movement work in ______________ or ______________ ______________. When a muscle contracts, it ______________ on the bone it's attached to. One muscle group pulls the leg ______________, the other muscle group pulls the leg ______________. Before any of that can happen, the brain gets an ______________ ______________ ______________ and tells the brain to move, and the muscles ______________, pulling the ______________ that pull the leg up and down. THE RESPIRATORY AND CIRCULATORY SYSTEM The respiratory system involves the ______________ and all of its passageways, which performs an exchange of ______________. The circulatory system involves the ______________ and all the ______________ ______________. Animals breathe through their nose and mouth. The air travels to its ______________ through tiny branches called ______________. Those branches empty into these very thin walled air sacs called ______________. The walls of alveoli are so thin that gasses like ______________ and ______________ ______________ can pass through them. ______________ begins when oxygen-poor blood enters the ______________. The heart notices and sends the blood to the lungs, where it becomes oxygen-rich. The oxygen-rich blood pumps back to the heart. The heart needs ______________ so the blood goes to the small intestine and picks up nutrients. Now that it's nutrient and oxygen-rich, it can be delivered to any other body part, and then it goes through that circle again. The blood travels in the ______________ and ______________ (tiny vessels). The dissolved nutrients can pass through their thin walls and enter the ______________. Cells pass their ______________ ______________ back through those capillaries and they get in the blood, which becomes oxygen-poor again, and it keeps going through the cycle. There are ______________ and ______________ circulatory systems. All vertebrates and some other animals have closed circulatory systems: ______________ ______________ ______________. Arthropods, mollusks, and other invertebrates have open systems: ______________ ______________ ______________. THE DIGESTIVE SYSTEM The digestive system is where all an animal’s food is broken down into ______________ and that's how animals get the ______________ they need. The animal chews its food with its teeth, and its ______________ breaks down the food so it’s small enough to travel down his ______________. NOTE: Saliva is made of 99% water. This is no surprise considering the body is made of 60% water. The remaining 1% of saliva contains digestive enzymes, uric acid, electrolytes, mucus-forming proteins, and cholesterol. As it travels down the ______________, it's going to enter the ______________. The ______________ will hold the food until it's partially ______________. The strong ______________ ______________ break down the food. The esophagus gets the food to the stomach using a ______________ motion. It's like an ______________ that ______________ and ______________ and it pushes food all the way down into the stomach. After it's been digested, the food is going to empty into the ______________. ______________ ______________ are produced by the ______________ and the ______________ to break down the ______________, the ______________, and ______________ into nutrients that are then absorbed by the ______________ ______________. NOTE: Digestive or gastric juice is made up of digestive enzymes, hydrochloric acid, and other substances that are important for absorbing nutrients. This is where the food that becomes the ______________ get into the ______________. As blood travels from the ______________ down to the small intestine and picks nutrients up. The ______________ ______________ absorbs all the ______________ and the ______________ parts. The ______________ ______________ goes to the small intestine and the ______________ goes into the large intestine. It becomes more solid and travels to the ______________ and out. THE EXCRETORY SYSTEM The ______________ system ______________ ______________ ______________ from the body, too. It removes excess ______________ and ______________. Cells create waste, including ______________ ______________ and ______________. ______________ ______________ is removed through the ______________. The nitrogen waste is sent through the ______________ from the ______________ to the ______________. The liver breaks it down into ______________. Note: A toxin is a ______________ substance. The kidneys filter the waste from the blood using tiny filters called ______________. The ______________ separates ______________ from ______________ ______________. Useful substances are allowed to go back into the ______________ and nephrons collect the waste. ______________ is the collected waste from the nephrons. Urine travels from the ______________ to the ______________ and once it's full, the ______________ carries urine from the bladder outside of the body. THE NERVOUS AND ENDOCRINE SYSTEM The ______________ system in a vertebrate includes the ______________, ______________, the ______________ ______________, and ______________ ______________. It works with the ______________ system which contains all of the ______________. Hormones are ______________ that are released into the bloodstream that change how the body acts. If a rabbit saw a predator it might decide that it needs to run. Its nerves would relay that message. The nerves in its eyes spot the predator, nerves carry the signals to the brain, the brain sends the signal through nerves to the muscles, telling them to move. As it runs it senses that it needs to run faster. The ______________ ______________ would send out a ______________: ______________. Adrenaline increases the heart rate and that sends extra blood to the muscles. That gets it running faster and gets the rabbit’s body ready for anything. THE SKELETAL SYSTEM bones shortens electric nerve signal power opposing groups protect soft organs structure tendons move, own pulls up movement ligaments tendons pair down contract THE DIGESTIVE SYSTEM nutrients esophagus nourishment stomach acids contracts accordion saliva stomach good stuff esophagus sugars expands digested stomach rectum squeezing small intestine fats liver pancreas intestines the proteins digestive juices water nutrients waste bloodstream undigested large intestine heart THE EXCRETORY SYSTEM kidneys excretory salt nephrons liver carbon dioxide removes waste products lungs carbon dioxide water kidneys bladder nephron urine poisonous useful material blood nitrogen urethra toxins waste blood THE RESPIRATORY AND CIRCULATORY SYSTEM lungs blood vessels gasses bronchi heart veins nutrients lungs blood carried in blood vessels alveoli heart oxygen capillaries open carbon dioxide blood moves in an open cavity cells circulation closed waste materials THE NERVOUS AND ENDOCRINE SYSTEM brain endocrine chemicals adrenaline nerves sense organs hormones nerve cord endocrine system nervous hormone