Functions of Human Body Systems
The human body is a complex organism made up of several individual systems working together to create a balance known as "homeostasis." This balance is required to enable full function and survival. Without these systems, we would not be able to move, eat, defend against disease, eliminate waste from the body, create offspring, circulate blood or breathe.
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Circulation and Oxygenation
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The cardiovascular and respiratory system work together to provide oxygen and vital nutrients to the body. The respiratory system consists of the nose, throat, trachea, larynx and lungs. Outside air is brought in through the nose or mouth, where it is cleaned of impurities such as mold spores and dust before it is sent down the throat into the lungs. Oxygen is exchanged with carbon dioxide and exhaled back out. Blood from the heart is sent into the lungs to be oxygenated before it is dispersed to the rest of the body through the cardiovascular system, which is made up of the heart and circulatory system. The continuous loop carries fresh, oxygenated blood through the body via the arteries. From there, it is sent to the capillaries, which nourish the cells, then sent back to the heart through veins to be oxygenated again.
Control Centers
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The brain, spinal cord and a vast network of nerves make up the nervous system. Without this system, we couldn't think, feel, move or express emotion. It sends signals to every other system in the body and controls the fast processes. Neurons move back and forth along the system, carrying external information to the brain and relaying commands from the brain. The endocrine system releases hormones that control or influence just about every type of cell in the body. The glands that make up the system include the hypothalamus, pituitary, thyroid, parathyroids, adrenal, pineal, ovaries and testes. Hormones are sent through the blood stream to different cells and the slow processes in the body such as growth, reproduction and metabolism.
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Digestion and Elimination
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The digestive system consists of all the organs required to process food, including the mouth, esophagus, stomach, small intestines, large intestines, liver, pancreas and gallbladder. Food is broken down in the mouth, sent through the esophagus and pushed into the stomach. Acids and enzymes break it down further and push it through the intestines where nutrients are removed. Solid waste is expelled from the colon. The liver, pancreas and gallbladder add digestive juices to help the process. The urinary system removes liquid waste, toxins and excess salt. It includes the kidneys, bladder, ureters and urethra. The kidneys also ensure that the body has a healthy level of fluids to circulate through the systems and to keep the tissues alive and filter the blood of impurities.
Defense
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The lymphatic system is a defense system made up of lymph nodes, bone marrow, the spleen and the thymus. This system is responsible for distributing lymph fluids throughout the body, making lymphocytes to protect against disease and absorbing fats from the intestines. The lymphatic system also removes impurities from the blood, including dead blood cells.
Reproduction
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The male and female reproductive systems are different from each other in structure, but together, they are responsible for creating offspring. The female reproductive system is made up of the vagina, uterus, ovaries and fallopian tubes. Testicles, the penis, the duct system and accessory glands make up the male system. This is the only system in the body we do not need for survival.
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