Body+Systems

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 * ** Circulatory System ** || ** Respiratory System ** || ** Excretory System ** ||
 * All cells in the body need to have oxygen and nutrients, and they need their wastes removed. These are the main roles of the circulatory system. The heart, blood and blood vessels work together to service the cells of the body. Using the network of arteries, veins and capillaries, blood ferries carbon dioxide to the lungs (for exhalation) and picks up oxygen. From the small intestine, the blood gathers food nutrients and delivers them to every cell. || The main role of the Respiratory System is the inhalation of fresh oxygen (O2) needed by the body's cells and the exhalation of waste carbon dioxide (CO2). It also helps maintain body temperature and eliminate excess water from the body. The Respiratory system is dependent on the proper functioning of the circulatory system as the O2 and waste CO2 are carried in the blood stream. || The job of the excretory system is to remove various produced by the body. The removal is known as excreation. It is important for the body to remove these various waste, also known as toxic, because toxic build up can lead to servere death. ||

**Gaseous exchange and body transport systems**

 * **Insect** || **Fish** || **Frog** || **Mammal** ||
 * __Tracheal system__- network of tubes located throughout the body through which air passes

__Spiricals__- holes in the respiratory system located on the abdomen, openings into internal tubes

__Tracheae__- largest branch in the body, leads onto smaller branches, tracheoles

Air enters the spiricals, travels along the tracheae and into the tracheoles; here the oxygen diffuses into the cells. || __Gills-__ folding of the body wall supported by bony gill arches

__Gill filaments-__ fleshy part of gills where oxygen is absorbed from the water into the blood stream

Fish breathes in water which flows out over the gills. Blood flows into the gill filaments, oxygen from the water flows in and carbon dioxide returning from the body flows out with the water. || Frogs have small lungs which they fill with air by gulping. The frog lowers the floor of its mouth, closing the path to its lungs, and then it inhales through its nostrils. They then close their nostrils and open the path to their lungs and raise the floor of their mouth to push air into the lungs. They then let out the carbon dioxide through their mouths. Carbon dioxide can diffuse through the surface of their skin. For clearer understanding refer to Figure 2.4.5 page 132 || __Trachea-__ entrance pipe to your lungs

__Pharynx-__ where food and air meet

__Larynx-__ closes entrance to your trachea, where the epiglottis and voice box are

__Bronchi-__ pathways leading to lungs

__Alveoli-__ air sacs where oxygen diffuse into blood stream through capillaries

Air is breathes in the nose and mouth, it then travels down the trachea to the pharynx where the larynx stops food from continuing down the trachea and air continues to the bronchi. The air travels into the lungs via the bronchi and down into the alveoli where oxygen is diffused into the capillaries to travel around to the cells through the blood stream and carbon dioxide is diffused into the alveoli to be breathed out. ||

Vertebrates, and a few invertebrates, have a closed circulatory system. Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness. In this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities. || The open circulatory system is common to molluscs and arthropods. Open circulatory systems (evolved in crustaceans, insects, mollusks and other invertebrates) pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells. Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood. ||
 * ** Closed Circulatory System ** || ** Open Circulatory System ** ||
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