The function of nutrition gives our cells energy and oxygen. The digestive , respiratory ,circulatory and excretory system take part in nutrition.
Digestion is the process in which food changes into nutrients.It takes place in the digestive system , which has two parts:·Te digestive tract : it is a long muscular tube abouteight metres long. Its parts are themouth, pharynx, oesophagus, stomach, small intestine andlarge intestine.· Glands : They release chemicals to the digestive tract tohelp with digestion . They are the salivary glands, the liverand the pancreas.
Breathing is the process where the body takes in oxygen and releases carbon dioxide. Lung ventilation: Inhaling is when air goes into lungs. Exchange of gases: The oxygen breathed in goes to the blood and the carbon dioxide from the blood moves to the lungs where it is released outside the body.
Respiratory tract: It is made made up of passagesthroung which air enters and leaves the body. Lungs: They are two spongy organs made up of millions of small bags called alveoli, where gases are exchanged.
Excretion is the elimination of the wastesubstances collected in the blood that cellshave produced. The excretory system is incharge of excretion and it is made up of: Sweat glands They are in the skin and produce sweat. Urinary system
_ Kidneys They take substances out of theblood, mix it with some water and make urine._ Urinary tract It takes, stores and releases theurine.
Circulation is the transportation of bloodthroungh the circulatory system. Heart: It is a hollow, muscular organ that pumps blood so that it reaches the entire body.
Blood It collects oxygen from the alveoliAnd nutrients from the small intestine andtransports them to all of the body. Blood vessels They are the tubes through which blood circulates. _ Arteries They are blood vessels that carryblood from the heart to the rest of the body. _ Veins They are the blood vessels that carryentire body back to the heart.
_ Capillaries They are very thin vessels thatreach all the cells of the body.
BLOODBlood is a read liquid tissue made up ofcells that float the nutrition liquid calledplasma. Blood cells There are different types of cells. _ Red blood cells: Most are of this type._ White blood cells: They are the body´sdefence.
_ Platelets They form blood clots in bloodvessels to stop blood form coming out whenthey are broken. Blood plasma It is a liquid made up of water with dissolved salts and nutrients.
It is a muscular organ located in the chest.It is divided into two parts separated by a wallcalled the heart septum. Atrium It is the upper cavity. Ventricle The cavity is smaller. Systole: It is the movement of contraction. Diastole: It is the movement of relaxation.
Mammals have a closed circulation becauseblood full of oxygen or carbon dioxide do notmix.
Human circulation is double because it has apulmonary or minor circulation and a general ormajor circulation.